Closes #20564: Many-to-many pass-through port mappings (#20851)

netbox/dcim/api/serializers_/base.py

@@ -2,10 +2,12 @@ from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import extend_schema_field
 from rest_framework import serializers
 
+from dcim.models import FrontPort, FrontPortTemplate, PortMapping, PortTemplateMapping, RearPort, RearPortTemplate
 from utilities.api import get_serializer_for_model
 
 __all__ = (
     'ConnectedEndpointsSerializer',
+    'PortSerializer',
 )
 
 
@@ -35,3 +37,53 @@ class ConnectedEndpointsSerializer(serializers.ModelSerializer):
     @extend_schema_field(serializers.BooleanField)
     def get_connected_endpoints_reachable(self, obj):
         return obj._path and obj._path.is_complete and obj._path.is_active
+
+
+class PortSerializer(serializers.ModelSerializer):
+    """
+    Base serializer for front & rear port and port templates.
+    """
+    @property
+    def _mapper(self):
+        """
+        Return the model and ForeignKey field name used to track port mappings for this model.
+        """
+        if self.Meta.model is FrontPort:
+            return PortMapping, 'front_port'
+        if self.Meta.model is RearPort:
+            return PortMapping, 'rear_port'
+        if self.Meta.model is FrontPortTemplate:
+            return PortTemplateMapping, 'front_port'
+        if self.Meta.model is RearPortTemplate:
+            return PortTemplateMapping, 'rear_port'
+        raise ValueError(f"Could not determine mapping details for {self.__class__}")
+
+    def create(self, validated_data):
+        mappings = validated_data.pop('mappings', [])
+        instance = super().create(validated_data)
+
+        # Create port mappings
+        mapping_model, fk_name = self._mapper
+        for attrs in mappings:
+            mapping_model.objects.create(**{
+                fk_name: instance,
+                **attrs,
+            })
+
+        return instance
+
+    def update(self, instance, validated_data):
+        mappings = validated_data.pop('mappings', None)
+        instance = super().update(instance, validated_data)
+
+        if mappings is not None:
+            # Update port mappings
+            mapping_model, fk_name = self._mapper
+            mapping_model.objects.filter(**{fk_name: instance}).delete()
+            for attrs in mappings:
+                mapping_model.objects.create(**{
+                    fk_name: instance,
+                    **attrs,
+                })
+
+        return instance

netbox/dcim/api/serializers_/device_components.py

@@ -5,21 +5,21 @@ from rest_framework import serializers
 from dcim.choices import *
 from dcim.constants import *
 from dcim.models import (
-    ConsolePort, ConsoleServerPort, DeviceBay, FrontPort, Interface, InventoryItem, ModuleBay, PowerOutlet, PowerPort,
-    RearPort, VirtualDeviceContext,
+    ConsolePort, ConsoleServerPort, DeviceBay, FrontPort, Interface, InventoryItem, ModuleBay, PortMapping,
+    PowerOutlet, PowerPort, RearPort, VirtualDeviceContext,
 )
 from ipam.api.serializers_.vlans import VLANSerializer, VLANTranslationPolicySerializer
 from ipam.api.serializers_.vrfs import VRFSerializer
 from ipam.models import VLAN
 from netbox.api.fields import ChoiceField, ContentTypeField, SerializedPKRelatedField
 from netbox.api.gfk_fields import GFKSerializerField
-from netbox.api.serializers import NetBoxModelSerializer, WritableNestedSerializer
+from netbox.api.serializers import NetBoxModelSerializer
 from vpn.api.serializers_.l2vpn import L2VPNTerminationSerializer
 from wireless.api.serializers_.nested import NestedWirelessLinkSerializer
 from wireless.api.serializers_.wirelesslans import WirelessLANSerializer
 from wireless.choices import *
 from wireless.models import WirelessLAN
-from .base import ConnectedEndpointsSerializer
+from .base import ConnectedEndpointsSerializer, PortSerializer
 from .cables import CabledObjectSerializer
 from .devices import DeviceSerializer, MACAddressSerializer, ModuleSerializer, VirtualDeviceContextSerializer
 from .manufacturers import ManufacturerSerializer
@@ -294,7 +294,20 @@ class InterfaceSerializer(NetBoxModelSerializer, CabledObjectSerializer, Connect
         return super().validate(data)
 
 
-class RearPortSerializer(NetBoxModelSerializer, CabledObjectSerializer):
+class RearPortMappingSerializer(serializers.ModelSerializer):
+    position = serializers.IntegerField(
+        source='rear_port_position'
+    )
+    front_port = serializers.PrimaryKeyRelatedField(
+        queryset=FrontPort.objects.all(),
+    )
+
+    class Meta:
+        model = PortMapping
+        fields = ('position', 'front_port', 'front_port_position')
+
+
+class RearPortSerializer(NetBoxModelSerializer, CabledObjectSerializer, PortSerializer):
     device = DeviceSerializer(nested=True)
     module = ModuleSerializer(
         nested=True,
@@ -303,28 +316,36 @@ class RearPortSerializer(NetBoxModelSerializer, CabledObjectSerializer):
         allow_null=True
     )
     type = ChoiceField(choices=PortTypeChoices)
+    front_ports = RearPortMappingSerializer(
+        source='mappings',
+        many=True,
+        required=False,
+    )
 
     class Meta:
         model = RearPort
         fields = [
             'id', 'url', 'display_url', 'display', 'device', 'module', 'name', 'label', 'type', 'color', 'positions',
-            'description', 'mark_connected', 'cable', 'cable_end', 'link_peers', 'link_peers_type', 'tags',
-            'custom_fields', 'created', 'last_updated', '_occupied',
+            'front_ports', 'description', 'mark_connected', 'cable', 'cable_end', 'link_peers', 'link_peers_type',
+            'tags', 'custom_fields', 'created', 'last_updated', '_occupied',
         ]
         brief_fields = ('id', 'url', 'display', 'device', 'name', 'description', 'cable', '_occupied')
 
 
-class FrontPortRearPortSerializer(WritableNestedSerializer):
-    """
-    NestedRearPortSerializer but with parent device omitted (since front and rear ports must belong to same device)
-    """
+class FrontPortMappingSerializer(serializers.ModelSerializer):
+    position = serializers.IntegerField(
+        source='front_port_position'
+    )
+    rear_port = serializers.PrimaryKeyRelatedField(
+        queryset=RearPort.objects.all(),
+    )
 
     class Meta:
-        model = RearPort
-        fields = ['id', 'url', 'display_url', 'display', 'name', 'label', 'description']
+        model = PortMapping
+        fields = ('position', 'rear_port', 'rear_port_position')
 
 
-class FrontPortSerializer(NetBoxModelSerializer, CabledObjectSerializer):
+class FrontPortSerializer(NetBoxModelSerializer, CabledObjectSerializer, PortSerializer):
     device = DeviceSerializer(nested=True)
     module = ModuleSerializer(
         nested=True,
@@ -333,14 +354,18 @@ class FrontPortSerializer(NetBoxModelSerializer, CabledObjectSerializer):
         allow_null=True
     )
     type = ChoiceField(choices=PortTypeChoices)
-    rear_port = FrontPortRearPortSerializer()
+    rear_ports = FrontPortMappingSerializer(
+        source='mappings',
+        many=True,
+        required=False,
+    )
 
     class Meta:
         model = FrontPort
         fields = [
-            'id', 'url', 'display_url', 'display', 'device', 'module', 'name', 'label', 'type', 'color', 'rear_port',
-            'rear_port_position', 'description', 'mark_connected', 'cable', 'cable_end', 'link_peers',
-            'link_peers_type', 'tags', 'custom_fields', 'created', 'last_updated', '_occupied',
+            'id', 'url', 'display_url', 'display', 'device', 'module', 'name', 'label', 'type', 'color', 'positions',
+            'rear_ports', 'description', 'mark_connected', 'cable', 'cable_end', 'link_peers', 'link_peers_type',
+            'tags', 'custom_fields', 'created', 'last_updated', '_occupied',
         ]
         brief_fields = ('id', 'url', 'display', 'device', 'name', 'description', 'cable', '_occupied')
 

netbox/dcim/api/serializers_/devicetype_components.py

@@ -5,12 +5,14 @@ from dcim.choices import *
 from dcim.constants import *
 from dcim.models import (
     ConsolePortTemplate, ConsoleServerPortTemplate, DeviceBayTemplate, FrontPortTemplate, InterfaceTemplate,
-    InventoryItemTemplate, ModuleBayTemplate, PowerOutletTemplate, PowerPortTemplate, RearPortTemplate,
+    InventoryItemTemplate, ModuleBayTemplate, PortTemplateMapping, PowerOutletTemplate, PowerPortTemplate,
+    RearPortTemplate,
 )
 from netbox.api.fields import ChoiceField, ContentTypeField
 from netbox.api.gfk_fields import GFKSerializerField
 from netbox.api.serializers import ChangeLogMessageSerializer, ValidatedModelSerializer
 from wireless.choices import *
+from .base import PortSerializer
 from .devicetypes import DeviceTypeSerializer, ModuleTypeSerializer
 from .manufacturers import ManufacturerSerializer
 from .nested import NestedInterfaceTemplateSerializer
@@ -205,7 +207,20 @@ class InterfaceTemplateSerializer(ComponentTemplateSerializer):
         brief_fields = ('id', 'url', 'display', 'name', 'description')
 
 
-class RearPortTemplateSerializer(ComponentTemplateSerializer):
+class RearPortTemplateMappingSerializer(serializers.ModelSerializer):
+    position = serializers.IntegerField(
+        source='rear_port_position'
+    )
+    front_port = serializers.PrimaryKeyRelatedField(
+        queryset=FrontPortTemplate.objects.all(),
+    )
+
+    class Meta:
+        model = PortTemplateMapping
+        fields = ('position', 'front_port', 'front_port_position')
+
+
+class RearPortTemplateSerializer(ComponentTemplateSerializer, PortSerializer):
     device_type = DeviceTypeSerializer(
         required=False,
         nested=True,
@@ -219,17 +234,35 @@ class RearPortTemplateSerializer(ComponentTemplateSerializer):
         default=None
     )
     type = ChoiceField(choices=PortTypeChoices)
+    front_ports = RearPortTemplateMappingSerializer(
+        source='mappings',
+        many=True,
+        required=False,
+    )
 
     class Meta:
         model = RearPortTemplate
         fields = [
-            'id', 'url', 'display', 'device_type', 'module_type', 'name', 'label', 'type', 'color',
-            'positions', 'description', 'created', 'last_updated',
+            'id', 'url', 'display', 'device_type', 'module_type', 'name', 'label', 'type', 'color', 'positions',
+            'front_ports', 'description', 'created', 'last_updated',
         ]
         brief_fields = ('id', 'url', 'display', 'name', 'description')
 
 
-class FrontPortTemplateSerializer(ComponentTemplateSerializer):
+class FrontPortTemplateMappingSerializer(serializers.ModelSerializer):
+    position = serializers.IntegerField(
+        source='front_port_position'
+    )
+    rear_port = serializers.PrimaryKeyRelatedField(
+        queryset=RearPortTemplate.objects.all(),
+    )
+
+    class Meta:
+        model = PortTemplateMapping
+        fields = ('position', 'rear_port', 'rear_port_position')
+
+
+class FrontPortTemplateSerializer(ComponentTemplateSerializer, PortSerializer):
     device_type = DeviceTypeSerializer(
         nested=True,
         required=False,
@@ -243,13 +276,17 @@ class FrontPortTemplateSerializer(ComponentTemplateSerializer):
         default=None
     )
     type = ChoiceField(choices=PortTypeChoices)
-    rear_port = RearPortTemplateSerializer(nested=True)
+    rear_ports = FrontPortTemplateMappingSerializer(
+        source='mappings',
+        many=True,
+        required=False,
+    )
 
     class Meta:
         model = FrontPortTemplate
         fields = [
-            'id', 'url', 'display', 'device_type', 'module_type', 'name', 'label', 'type', 'color',
-            'rear_port', 'rear_port_position', 'description', 'created', 'last_updated',
+            'id', 'url', 'display', 'device_type', 'module_type', 'name', 'label', 'type', 'color', 'positions',
+            'rear_ports', 'description', 'created', 'last_updated',
         ]
         brief_fields = ('id', 'url', 'display', 'name', 'description')
 

netbox/dcim/constants.py

@@ -32,8 +32,8 @@ CABLE_POSITION_MAX = 1024
 # RearPorts
 #
 
-REARPORT_POSITIONS_MIN = 1
-REARPORT_POSITIONS_MAX = 1024
+PORT_POSITION_MIN = 1
+PORT_POSITION_MAX = 1024
 
 
 #

netbox/dcim/filtersets.py

@@ -904,12 +904,15 @@ class FrontPortTemplateFilterSet(ChangeLoggedModelFilterSet, ModularDeviceTypeCo
         null_value=None
     )
     rear_port_id = django_filters.ModelMultipleChoiceFilter(
-        queryset=RearPort.objects.all()
+        field_name='mappings__rear_port',
+        queryset=RearPort.objects.all(),
+        to_field_name='rear_port',
+        label=_('Rear port (ID)'),
     )
 
     class Meta:
         model = FrontPortTemplate
-        fields = ('id', 'name', 'label', 'type', 'color', 'rear_port_position', 'description')
+        fields = ('id', 'name', 'label', 'type', 'color', 'positions', 'description')
 
 
 @register_filterset
@@ -918,6 +921,12 @@ class RearPortTemplateFilterSet(ChangeLoggedModelFilterSet, ModularDeviceTypeCom
         choices=PortTypeChoices,
         null_value=None
     )
+    front_port_id = django_filters.ModelMultipleChoiceFilter(
+        field_name='mappings__front_port',
+        queryset=FrontPort.objects.all(),
+        to_field_name='front_port',
+        label=_('Front port (ID)'),
+    )
 
     class Meta:
         model = RearPortTemplate
@@ -2148,13 +2157,16 @@ class FrontPortFilterSet(ModularDeviceComponentFilterSet, CabledObjectFilterSet)
         null_value=None
     )
     rear_port_id = django_filters.ModelMultipleChoiceFilter(
-        queryset=RearPort.objects.all()
+        field_name='mappings__rear_port',
+        queryset=RearPort.objects.all(),
+        to_field_name='rear_port',
+        label=_('Rear port (ID)'),
     )
 
     class Meta:
         model = FrontPort
         fields = (
-            'id', 'name', 'label', 'type', 'color', 'rear_port_position', 'description', 'mark_connected', 'cable_end',
+            'id', 'name', 'label', 'type', 'color', 'positions', 'description', 'mark_connected', 'cable_end',
             'cable_position',
         )
 
@@ -2165,6 +2177,12 @@ class RearPortFilterSet(ModularDeviceComponentFilterSet, CabledObjectFilterSet):
         choices=PortTypeChoices,
         null_value=None
     )
+    front_port_id = django_filters.ModelMultipleChoiceFilter(
+        field_name='mappings__front_port',
+        queryset=FrontPort.objects.all(),
+        to_field_name='front_port',
+        label=_('Front port (ID)'),
+    )
 
     class Meta:
         model = RearPort

netbox/dcim/forms/bulk_import.py

@@ -1091,12 +1091,6 @@ class FrontPortImportForm(OwnerCSVMixin, NetBoxModelImportForm):
         queryset=Device.objects.all(),
         to_field_name='name'
     )
-    rear_port = CSVModelChoiceField(
-        label=_('Rear port'),
-        queryset=RearPort.objects.all(),
-        to_field_name='name',
-        help_text=_('Corresponding rear port')
-    )
     type = CSVChoiceField(
         label=_('Type'),
         choices=PortTypeChoices,
@@ -1106,32 +1100,9 @@ class FrontPortImportForm(OwnerCSVMixin, NetBoxModelImportForm):
     class Meta:
         model = FrontPort
         fields = (
-            'device', 'name', 'label', 'type', 'color', 'mark_connected', 'rear_port', 'rear_port_position',
-            'description', 'owner', 'tags'
+            'device', 'name', 'label', 'type', 'color', 'mark_connected', 'positions', 'description', 'owner', 'tags'
         )
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-
-        # Limit RearPort choices to those belonging to this device (or VC master)
-        if self.is_bound and 'device' in self.data:
-            try:
-                device = self.fields['device'].to_python(self.data['device'])
-            except forms.ValidationError:
-                device = None
-        else:
-            try:
-                device = self.instance.device
-            except Device.DoesNotExist:
-                device = None
-
-        if device:
-            self.fields['rear_port'].queryset = RearPort.objects.filter(
-                device__in=[device, device.get_vc_master()]
-            )
-        else:
-            self.fields['rear_port'].queryset = RearPort.objects.none()
-
 
 class RearPortImportForm(OwnerCSVMixin, NetBoxModelImportForm):
     device = CSVModelChoiceField(

netbox/dcim/forms/mixins.py

@@ -1,10 +1,12 @@
 from django import forms
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.db import connection
+from django.db.models.signals import post_save
 from django.utils.translation import gettext_lazy as _
 
 from dcim.constants import LOCATION_SCOPE_TYPES
-from dcim.models import Site
+from dcim.models import PortMapping, PortTemplateMapping, Site
 from utilities.forms import get_field_value
 from utilities.forms.fields import (
     ContentTypeChoiceField, CSVContentTypeField, DynamicModelChoiceField,
@@ -13,6 +15,7 @@ from utilities.templatetags.builtins.filters import bettertitle
 from utilities.forms.widgets import HTMXSelect
 
 __all__ = (
+    'FrontPortFormMixin',
     'ScopedBulkEditForm',
     'ScopedForm',
     'ScopedImportForm',
@@ -128,3 +131,75 @@ class ScopedImportForm(forms.Form):
                     "Please select a {scope_type}."
                 ).format(scope_type=scope_type.model_class()._meta.model_name)
             })
+
+
+class FrontPortFormMixin(forms.Form):
+    rear_ports = forms.MultipleChoiceField(
+        choices=[],
+        label=_('Rear ports'),
+        widget=forms.SelectMultiple(attrs={'size': 8})
+    )
+
+    port_mapping_model = PortMapping
+    parent_field = 'device'
+
+    def clean(self):
+        super().clean()
+
+        # Check that the total number of FrontPorts and positions matches the selected number of RearPort:position
+        # mappings. Note that `name` will be a list under FrontPortCreateForm, in which cases we multiply the number of
+        # FrontPorts being creation by the number of positions.
+        positions = self.cleaned_data['positions']
+        frontport_count = len(self.cleaned_data['name']) if type(self.cleaned_data['name']) is list else 1
+        rearport_count = len(self.cleaned_data['rear_ports'])
+        if frontport_count * positions != rearport_count:
+            raise forms.ValidationError({
+                'rear_ports': _(
+                    "The total number of front port positions ({frontport_count}) must match the selected number of "
+                    "rear port positions ({rearport_count})."
+                ).format(
+                    frontport_count=frontport_count,
+                    rearport_count=rearport_count
+                )
+            })
+
+    def _save_m2m(self):
+        super()._save_m2m()
+
+        # TODO: Can this be made more efficient?
+        # Delete existing rear port mappings
+        self.port_mapping_model.objects.filter(front_port_id=self.instance.pk).delete()
+
+        # Create new rear port mappings
+        mappings = []
+        if self.port_mapping_model is PortTemplateMapping:
+            params = {
+                'device_type_id': self.instance.device_type_id,
+                'module_type_id': self.instance.module_type_id,
+            }
+        else:
+            params = {
+                'device_id': self.instance.device_id,
+            }
+        for i, rp_position in enumerate(self.cleaned_data['rear_ports'], start=1):
+            rear_port_id, rear_port_position = rp_position.split(':')
+            mappings.append(
+                self.port_mapping_model(**{
+                    **params,
+                    'front_port_id': self.instance.pk,
+                    'front_port_position': i,
+                    'rear_port_id': rear_port_id,
+                    'rear_port_position': rear_port_position,
+                })
+            )
+        self.port_mapping_model.objects.bulk_create(mappings)
+        # Send post_save signals
+        for mapping in mappings:
+            post_save.send(
+                sender=PortMapping,
+                instance=mapping,
+                created=True,
+                raw=False,
+                using=connection,
+                update_fields=None
+            )

netbox/dcim/forms/model_forms.py

@@ -6,6 +6,7 @@ from timezone_field import TimeZoneFormField
 
 from dcim.choices import *
 from dcim.constants import *
+from dcim.forms.mixins import FrontPortFormMixin
 from dcim.models import *
 from extras.models import ConfigTemplate
 from ipam.choices import VLANQinQRoleChoices
@@ -1112,34 +1113,66 @@ class InterfaceTemplateForm(ModularComponentTemplateForm):
         ]
 
 
-class FrontPortTemplateForm(ModularComponentTemplateForm):
-    rear_port = DynamicModelChoiceField(
-        label=_('Rear port'),
-        queryset=RearPortTemplate.objects.all(),
-        required=False,
-        query_params={
-            'device_type_id': '$device_type',
-            'module_type_id': '$module_type',
-        }
-    )
-
+class FrontPortTemplateForm(FrontPortFormMixin, ModularComponentTemplateForm):
     fieldsets = (
         FieldSet(
             TabbedGroups(
                 FieldSet('device_type', name=_('Device Type')),
                 FieldSet('module_type', name=_('Module Type')),
             ),
-            'name', 'label', 'type', 'color', 'rear_port', 'rear_port_position', 'description',
+            'name', 'label', 'type', 'positions', 'rear_ports', 'description',
         ),
     )
 
+    # Override FrontPortFormMixin attrs
+    port_mapping_model = PortTemplateMapping
+    parent_field = 'device_type'
+
     class Meta:
         model = FrontPortTemplate
         fields = [
-            'device_type', 'module_type', 'name', 'label', 'type', 'color', 'rear_port', 'rear_port_position',
-            'description',
+            'device_type', 'module_type', 'name', 'label', 'type', 'color', 'positions', 'description',
+        ]
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        if device_type_id := self.data.get('device_type') or self.initial.get('device_type'):
+            device_type = DeviceType.objects.get(pk=device_type_id)
+        else:
+            return
+
+        # Populate rear port choices
+        self.fields['rear_ports'].choices = self._get_rear_port_choices(device_type, self.instance)
+
+        # Set initial rear port mappings
+        if self.instance.pk:
+            self.initial['rear_ports'] = [
+                f'{mapping.rear_port_id}:{mapping.rear_port_position}'
+                for mapping in PortTemplateMapping.objects.filter(front_port_id=self.instance.pk)
+            ]
+
+    def _get_rear_port_choices(self, device_type, front_port):
+        """
+        Return a list of choices representing each available rear port & position pair on the device type, excluding
+        those assigned to the specified instance.
+        """
+        occupied_rear_port_positions = [
+            f'{mapping.rear_port_id}:{mapping.rear_port_position}'
+            for mapping in device_type.port_mappings.exclude(front_port=front_port.pk)
         ]
 
+        choices = []
+        for rear_port in RearPortTemplate.objects.filter(device_type=device_type):
+            for i in range(1, rear_port.positions + 1):
+                pair_id = f'{rear_port.pk}:{i}'
+                if pair_id not in occupied_rear_port_positions:
+                    pair_label = f'{rear_port.name}:{i}'
+                    choices.append(
+                        (pair_id, pair_label)
+                    )
+        return choices
+
 
 class RearPortTemplateForm(ModularComponentTemplateForm):
     fieldsets = (
@@ -1578,17 +1611,10 @@ class InterfaceForm(InterfaceCommonForm, ModularDeviceComponentForm):
         }
 
 
-class FrontPortForm(ModularDeviceComponentForm):
-    rear_port = DynamicModelChoiceField(
-        queryset=RearPort.objects.all(),
-        query_params={
-            'device_id': '$device',
-        }
-    )
-
+class FrontPortForm(FrontPortFormMixin, ModularDeviceComponentForm):
     fieldsets = (
         FieldSet(
-            'device', 'module', 'name', 'label', 'type', 'color', 'rear_port', 'rear_port_position', 'mark_connected',
+            'device', 'module', 'name', 'label', 'type', 'color', 'positions', 'rear_ports', 'mark_connected',
             'description', 'tags',
         ),
     )
@@ -1596,10 +1622,49 @@ class FrontPortForm(ModularDeviceComponentForm):
     class Meta:
         model = FrontPort
         fields = [
-            'device', 'module', 'name', 'label', 'type', 'color', 'rear_port', 'rear_port_position', 'mark_connected',
-            'description', 'owner', 'tags',
+            'device', 'module', 'name', 'label', 'type', 'color', 'positions', 'mark_connected', 'description', 'owner',
+            'tags',
         ]
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        if device_id := self.data.get('device') or self.initial.get('device'):
+            device = Device.objects.get(pk=device_id)
+        else:
+            return
+
+        # Populate rear port choices
+        self.fields['rear_ports'].choices = self._get_rear_port_choices(device, self.instance)
+
+        # Set initial rear port mappings
+        if self.instance.pk:
+            self.initial['rear_ports'] = [
+                f'{mapping.rear_port_id}:{mapping.rear_port_position}'
+                for mapping in PortMapping.objects.filter(front_port_id=self.instance.pk)
+            ]
+
+    def _get_rear_port_choices(self, device, front_port):
+        """
+        Return a list of choices representing each available rear port & position pair on the device, excluding those
+        assigned to the specified instance.
+        """
+        occupied_rear_port_positions = [
+            f'{mapping.rear_port_id}:{mapping.rear_port_position}'
+            for mapping in device.port_mappings.exclude(front_port=front_port.pk)
+        ]
+
+        choices = []
+        for rear_port in RearPort.objects.filter(device=device):
+            for i in range(1, rear_port.positions + 1):
+                pair_id = f'{rear_port.pk}:{i}'
+                if pair_id not in occupied_rear_port_positions:
+                    pair_label = f'{rear_port.name}:{i}'
+                    choices.append(
+                        (pair_id, pair_label)
+                    )
+        return choices
+
 
 class RearPortForm(ModularDeviceComponentForm):
     fieldsets = (

netbox/dcim/forms/object_create.py

@@ -109,85 +109,30 @@ class InterfaceTemplateCreateForm(ComponentCreateForm, model_forms.InterfaceTemp
 
 
 class FrontPortTemplateCreateForm(ComponentCreateForm, model_forms.FrontPortTemplateForm):
-    rear_port = forms.MultipleChoiceField(
-        choices=[],
-        label=_('Rear ports'),
-        help_text=_('Select one rear port assignment for each front port being created.'),
-        widget=forms.SelectMultiple(attrs={'size': 6})
-    )
 
-    # Override fieldsets from FrontPortTemplateForm to omit rear_port_position
+    # Override fieldsets from FrontPortTemplateForm
     fieldsets = (
         FieldSet(
             TabbedGroups(
                 FieldSet('device_type', name=_('Device Type')),
                 FieldSet('module_type', name=_('Module Type')),
             ),
-            'name', 'label', 'type', 'color', 'rear_port', 'description',
+            'name', 'label', 'type', 'color', 'positions', 'rear_ports', 'description',
         ),
     )
 
-    class Meta(model_forms.FrontPortTemplateForm.Meta):
-        exclude = ('name', 'label', 'rear_port', 'rear_port_position')
-
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-
-        # TODO: This needs better validation
-        if 'device_type' in self.initial or self.data.get('device_type'):
-            parent = DeviceType.objects.get(
-                pk=self.initial.get('device_type') or self.data.get('device_type')
-            )
-        elif 'module_type' in self.initial or self.data.get('module_type'):
-            parent = ModuleType.objects.get(
-                pk=self.initial.get('module_type') or self.data.get('module_type')
-            )
-        else:
-            return
-
-        # Determine which rear port positions are occupied. These will be excluded from the list of available mappings.
-        occupied_port_positions = [
-            (front_port.rear_port_id, front_port.rear_port_position)
-            for front_port in parent.frontporttemplates.all()
-        ]
-
-        # Populate rear port choices
-        choices = []
-        rear_ports = parent.rearporttemplates.all()
-        for rear_port in rear_ports:
-            for i in range(1, rear_port.positions + 1):
-                if (rear_port.pk, i) not in occupied_port_positions:
-                    choices.append(
-                        ('{}:{}'.format(rear_port.pk, i), '{}:{}'.format(rear_port.name, i))
-                    )
-        self.fields['rear_port'].choices = choices
-
-    def clean(self):
-        super().clean()
-
-        # Check that the number of FrontPortTemplates to be created matches the selected number of RearPortTemplate
-        # positions
-        frontport_count = len(self.cleaned_data['name'])
-        rearport_count = len(self.cleaned_data['rear_port'])
-        if frontport_count != rearport_count:
-            raise forms.ValidationError({
-                'rear_port': _(
-                    "The number of front port templates to be created ({frontport_count}) must match the selected "
-                    "number of rear port positions ({rearport_count})."
-                ).format(
-                    frontport_count=frontport_count,
-                    rearport_count=rearport_count
-                )
-            })
+    class Meta:
+        model = FrontPortTemplate
+        fields = (
+            'device_type', 'module_type', 'type', 'color', 'positions', 'description',
+        )
 
     def get_iterative_data(self, iteration):
-
-        # Assign rear port and position from selected set
-        rear_port, position = self.cleaned_data['rear_port'][iteration].split(':')
+        positions = self.cleaned_data['positions']
+        offset = positions * iteration
 
         return {
-            'rear_port': int(rear_port),
-            'rear_port_position': int(position),
+            'rear_ports': self.cleaned_data['rear_ports'][offset:offset + positions]
         }
 
 
@@ -269,74 +214,26 @@ class FrontPortCreateForm(ComponentCreateForm, model_forms.FrontPortForm):
             }
         )
     )
-    rear_port = forms.MultipleChoiceField(
-        choices=[],
-        label=_('Rear ports'),
-        help_text=_('Select one rear port assignment for each front port being created.'),
-        widget=forms.SelectMultiple(attrs={'size': 6})
-    )
 
     # Override fieldsets from FrontPortForm to omit rear_port_position
     fieldsets = (
         FieldSet(
-            'device', 'module', 'name', 'label', 'type', 'color', 'rear_port', 'mark_connected', 'description', 'tags',
+            'device', 'module', 'name', 'label', 'type', 'color', 'positions', 'rear_ports', 'mark_connected',
+            'description', 'tags',
         ),
     )
 
-    class Meta(model_forms.FrontPortForm.Meta):
-        exclude = ('name', 'label', 'rear_port', 'rear_port_position')
-
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-
-        if device_id := self.data.get('device') or self.initial.get('device'):
-            device = Device.objects.get(pk=device_id)
-        else:
-            return
-
-        # Determine which rear port positions are occupied. These will be excluded from the list of available
-        # mappings.
-        occupied_port_positions = [
-            (front_port.rear_port_id, front_port.rear_port_position)
-            for front_port in device.frontports.all()
+    class Meta:
+        model = FrontPort
+        fields = [
+            'device', 'module', 'type', 'color', 'positions', 'mark_connected', 'description', 'owner', 'tags',
         ]
 
-        # Populate rear port choices
-        choices = []
-        rear_ports = RearPort.objects.filter(device=device)
-        for rear_port in rear_ports:
-            for i in range(1, rear_port.positions + 1):
-                if (rear_port.pk, i) not in occupied_port_positions:
-                    choices.append(
-                        ('{}:{}'.format(rear_port.pk, i), '{}:{}'.format(rear_port.name, i))
-                    )
-        self.fields['rear_port'].choices = choices
-
-    def clean(self):
-        super().clean()
-
-        # Check that the number of FrontPorts to be created matches the selected number of RearPort positions
-        frontport_count = len(self.cleaned_data['name'])
-        rearport_count = len(self.cleaned_data['rear_port'])
-        if frontport_count != rearport_count:
-            raise forms.ValidationError({
-                'rear_port': _(
-                    "The number of front ports to be created ({frontport_count}) must match the selected number of "
-                    "rear port positions ({rearport_count})."
-                ).format(
-                    frontport_count=frontport_count,
-                    rearport_count=rearport_count
-                )
-            })
-
     def get_iterative_data(self, iteration):
-
-        # Assign rear port and position from selected set
-        rear_port, position = self.cleaned_data['rear_port'][iteration].split(':')
-
+        positions = self.cleaned_data['positions']
+        offset = positions * iteration
         return {
-            'rear_port': int(rear_port),
-            'rear_port_position': int(position),
+            'rear_ports': self.cleaned_data['rear_ports'][offset:offset + positions]
         }
 
 

netbox/dcim/forms/object_import.py

@@ -13,6 +13,7 @@ __all__ = (
     'InterfaceTemplateImportForm',
     'InventoryItemTemplateImportForm',
     'ModuleBayTemplateImportForm',
+    'PortTemplateMappingImportForm',
     'PowerOutletTemplateImportForm',
     'PowerPortTemplateImportForm',
     'RearPortTemplateImportForm',
@@ -113,31 +114,11 @@ class FrontPortTemplateImportForm(forms.ModelForm):
         label=_('Type'),
         choices=PortTypeChoices.CHOICES
     )
-    rear_port = forms.ModelChoiceField(
-        label=_('Rear port'),
-        queryset=RearPortTemplate.objects.all(),
-        to_field_name='name'
-    )
-
-    def clean_device_type(self):
-        if device_type := self.cleaned_data['device_type']:
-            rear_port = self.fields['rear_port']
-            rear_port.queryset = rear_port.queryset.filter(device_type=device_type)
-
-        return device_type
-
-    def clean_module_type(self):
-        if module_type := self.cleaned_data['module_type']:
-            rear_port = self.fields['rear_port']
-            rear_port.queryset = rear_port.queryset.filter(module_type=module_type)
-
-        return module_type
 
     class Meta:
         model = FrontPortTemplate
         fields = [
-            'device_type', 'module_type', 'name', 'type', 'color', 'rear_port', 'rear_port_position', 'label',
-            'description',
+            'device_type', 'module_type', 'name', 'type', 'color', 'positions', 'label', 'description',
         ]
 
 
@@ -154,6 +135,25 @@ class RearPortTemplateImportForm(forms.ModelForm):
         ]
 
 
+class PortTemplateMappingImportForm(forms.ModelForm):
+    front_port = forms.ModelChoiceField(
+        label=_('Front port'),
+        queryset=FrontPortTemplate.objects.all(),
+        to_field_name='name',
+    )
+    rear_port = forms.ModelChoiceField(
+        label=_('Rear port'),
+        queryset=RearPortTemplate.objects.all(),
+        to_field_name='name',
+    )
+
+    class Meta:
+        model = PortTemplateMapping
+        fields = [
+            'front_port', 'front_port_position', 'rear_port', 'rear_port_position',
+        ]
+
+
 class ModuleBayTemplateImportForm(forms.ModelForm):
 
     class Meta:

netbox/dcim/graphql/filters.py

@@ -16,7 +16,8 @@ from dcim.graphql.filter_mixins import (
 from extras.graphql.filter_mixins import ConfigContextFilterMixin
 from netbox.graphql.filter_mixins import ImageAttachmentFilterMixin, WeightFilterMixin
 from netbox.graphql.filters import (
-    ChangeLoggedModelFilter, NestedGroupModelFilter, OrganizationalModelFilter, PrimaryModelFilter, NetBoxModelFilter,
+    BaseModelFilter, ChangeLoggedModelFilter, NestedGroupModelFilter, OrganizationalModelFilter, PrimaryModelFilter,
+    NetBoxModelFilter,
 )
 from tenancy.graphql.filter_mixins import ContactFilterMixin, TenancyFilterMixin
 from virtualization.models import VMInterface
@@ -70,6 +71,8 @@ __all__ = (
     'ModuleTypeFilter',
     'ModuleTypeProfileFilter',
     'PlatformFilter',
+    'PortMappingFilter',
+    'PortTemplateMappingFilter',
     'PowerFeedFilter',
     'PowerOutletFilter',
     'PowerOutletTemplateFilter',
@@ -404,13 +407,6 @@ class FrontPortFilter(ModularComponentFilterMixin, CabledObjectModelFilterMixin,
     color: BaseFilterLookup[Annotated['ColorEnum', strawberry.lazy('netbox.graphql.enums')]] | None = (
         strawberry_django.filter_field()
     )
-    rear_port: Annotated['RearPortFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
-        strawberry_django.filter_field()
-    )
-    rear_port_id: ID | None = strawberry_django.filter_field()
-    rear_port_position: Annotated['IntegerLookup', strawberry.lazy('netbox.graphql.filter_lookups')] | None = (
-        strawberry_django.filter_field()
-    )
 
 
 @strawberry_django.filter_type(models.FrontPortTemplate, lookups=True)
@@ -421,13 +417,37 @@ class FrontPortTemplateFilter(ModularComponentTemplateFilterMixin, ChangeLoggedM
     color: BaseFilterLookup[Annotated['ColorEnum', strawberry.lazy('netbox.graphql.enums')]] | None = (
         strawberry_django.filter_field()
     )
-    rear_port: Annotated['RearPortTemplateFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
+
+
+@strawberry_django.filter_type(models.PortMapping, lookups=True)
+class PortMappingFilter(BaseModelFilter):
+    device: Annotated['DeviceFilter', strawberry.lazy('dcim.graphql.filters')] | None = strawberry_django.filter_field()
+    front_port: Annotated['FrontPortFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
+        strawberry_django.filter_field()
+    )
+    rear_port: Annotated['RearPortFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
         strawberry_django.filter_field()
     )
-    rear_port_id: ID | None = strawberry_django.filter_field()
-    rear_port_position: Annotated['IntegerLookup', strawberry.lazy('netbox.graphql.filter_lookups')] | None = (
+    front_port_position: FilterLookup[int] | None = strawberry_django.filter_field()
+    rear_port_position: FilterLookup[int] | None = strawberry_django.filter_field()
+
+
+@strawberry_django.filter_type(models.PortTemplateMapping, lookups=True)
+class PortTemplateMappingFilter(BaseModelFilter):
+    device_type: Annotated['DeviceTypeFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
+        strawberry_django.filter_field()
+    )
+    module_type: Annotated['ModuleTypeFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
+        strawberry_django.filter_field()
+    )
+    front_port: Annotated['FrontPortTemplateFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
+        strawberry_django.filter_field()
+    )
+    rear_port: Annotated['RearPortTemplateFilter', strawberry.lazy('dcim.graphql.filters')] | None = (
         strawberry_django.filter_field()
     )
+    front_port_position: FilterLookup[int] | None = strawberry_django.filter_field()
+    rear_port_position: FilterLookup[int] | None = strawberry_django.filter_field()
 
 
 @strawberry_django.filter_type(models.MACAddress, lookups=True)

netbox/dcim/graphql/types.py

@@ -385,7 +385,8 @@ class DeviceTypeType(PrimaryObjectType):
 )
 class FrontPortType(ModularComponentType, CabledObjectMixin):
     color: str
-    rear_port: Annotated["RearPortType", strawberry.lazy('dcim.graphql.types')]
+
+    mappings: List[Annotated["PortMappingType", strawberry.lazy('dcim.graphql.types')]]
 
 
 @strawberry_django.type(
@@ -396,7 +397,8 @@ class FrontPortType(ModularComponentType, CabledObjectMixin):
 )
 class FrontPortTemplateType(ModularComponentTemplateType):
     color: str
-    rear_port: Annotated["RearPortTemplateType", strawberry.lazy('dcim.graphql.types')]
+
+    mappings: List[Annotated["PortMappingTemplateType", strawberry.lazy('dcim.graphql.types')]]
 
 
 @strawberry_django.type(
@@ -636,6 +638,28 @@ class PlatformType(NestedGroupObjectType):
     devices: List[Annotated["DeviceType", strawberry.lazy('dcim.graphql.types')]]
 
 
+@strawberry_django.type(
+    models.PortMapping,
+    fields='__all__',
+    filters=PortMappingFilter,
+    pagination=True
+)
+class PortMappingType(ModularComponentTemplateType):
+    front_port: Annotated["FrontPortType", strawberry.lazy('dcim.graphql.types')]
+    rear_port: Annotated["RearPortType", strawberry.lazy('dcim.graphql.types')]
+
+
+@strawberry_django.type(
+    models.PortTemplateMapping,
+    fields='__all__',
+    filters=PortTemplateMappingFilter,
+    pagination=True
+)
+class PortMappingTemplateType(ModularComponentTemplateType):
+    front_port: Annotated["FrontPortTemplateType", strawberry.lazy('dcim.graphql.types')]
+    rear_port: Annotated["RearPortTemplateType", strawberry.lazy('dcim.graphql.types')]
+
+
 @strawberry_django.type(
     models.PowerFeed,
     exclude=['_path'],
@@ -768,7 +792,7 @@ class RackRoleType(OrganizationalObjectType):
 class RearPortType(ModularComponentType, CabledObjectMixin):
     color: str
 
-    frontports: List[Annotated["FrontPortType", strawberry.lazy('dcim.graphql.types')]]
+    mappings: List[Annotated["PortMappingType", strawberry.lazy('dcim.graphql.types')]]
 
 
 @strawberry_django.type(
@@ -780,7 +804,7 @@ class RearPortType(ModularComponentType, CabledObjectMixin):
 class RearPortTemplateType(ModularComponentTemplateType):
     color: str
 
-    frontport_templates: List[Annotated["FrontPortTemplateType", strawberry.lazy('dcim.graphql.types')]]
+    mappings: List[Annotated["PortMappingTemplateType", strawberry.lazy('dcim.graphql.types')]]
 
 
 @strawberry_django.type(

netbox/dcim/migrations/0222_port_mappings.py

@@ -0,0 +1,219 @@
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations
+from django.db import models
+from itertools import islice
+
+
+def chunked(iterable, size):
+    """
+    Yield successive chunks of a given size from an iterator.
+    """
+    iterator = iter(iterable)
+    while chunk := list(islice(iterator, size)):
+        yield chunk
+
+
+def populate_port_template_mappings(apps, schema_editor):
+    FrontPortTemplate = apps.get_model('dcim', 'FrontPortTemplate')
+    PortTemplateMapping = apps.get_model('dcim', 'PortTemplateMapping')
+
+    front_ports = FrontPortTemplate.objects.iterator(chunk_size=1000)
+
+    def generate_copies():
+        for front_port in front_ports:
+            yield PortTemplateMapping(
+                device_type_id=front_port.device_type_id,
+                module_type_id=front_port.module_type_id,
+                front_port_id=front_port.pk,
+                front_port_position=1,
+                rear_port_id=front_port.rear_port_id,
+                rear_port_position=front_port.rear_port_position,
+            )
+
+    # Bulk insert in streaming batches
+    for chunk in chunked(generate_copies(), 1000):
+        PortTemplateMapping.objects.bulk_create(chunk, batch_size=1000)
+
+
+def populate_port_mappings(apps, schema_editor):
+    FrontPort = apps.get_model('dcim', 'FrontPort')
+    PortMapping = apps.get_model('dcim', 'PortMapping')
+
+    front_ports = FrontPort.objects.iterator(chunk_size=1000)
+
+    def generate_copies():
+        for front_port in front_ports:
+            yield PortMapping(
+                device_id=front_port.device_id,
+                front_port_id=front_port.pk,
+                front_port_position=1,
+                rear_port_id=front_port.rear_port_id,
+                rear_port_position=front_port.rear_port_position,
+            )
+
+    # Bulk insert in streaming batches
+    for chunk in chunked(generate_copies(), 1000):
+        PortMapping.objects.bulk_create(chunk, batch_size=1000)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('dcim', '0221_cable_position'),
+    ]
+
+    operations = [
+        # Create PortTemplateMapping model (for DeviceTypes)
+        migrations.CreateModel(
+            name='PortTemplateMapping',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False)),
+                (
+                    'front_port_position',
+                    models.PositiveSmallIntegerField(
+                        default=1,
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(1024)
+                        ]
+                    )
+                ),
+                (
+                    'rear_port_position',
+                    models.PositiveSmallIntegerField(
+                        default=1,
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(1024)
+                        ]
+                    )
+                ),
+                (
+                    'device_type',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.devicetype',
+                        related_name='port_mappings',
+                        blank=True,
+                        null=True
+                    )
+                ),
+                (
+                    'module_type',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.moduletype',
+                        related_name='port_mappings',
+                        blank=True,
+                        null=True
+                    )
+                ),
+                (
+                    'front_port',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.frontporttemplate',
+                        related_name='mappings'
+                    )
+                ),
+                (
+                    'rear_port',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.rearporttemplate',
+                        related_name='mappings'
+                    )
+                ),
+            ],
+        ),
+        migrations.AddConstraint(
+            model_name='porttemplatemapping',
+            constraint=models.UniqueConstraint(
+                fields=('front_port', 'front_port_position'),
+                name='dcim_porttemplatemapping_unique_front_port_position'
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name='porttemplatemapping',
+            constraint=models.UniqueConstraint(
+                fields=('rear_port', 'rear_port_position'),
+                name='dcim_porttemplatemapping_unique_rear_port_position'
+            ),
+        ),
+
+        # Create PortMapping model (for Devices)
+        migrations.CreateModel(
+            name='PortMapping',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False)),
+                (
+                    'front_port_position',
+                    models.PositiveSmallIntegerField(
+                        default=1,
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(1024)
+                        ]
+                    ),
+                ),
+                (
+                    'rear_port_position',
+                    models.PositiveSmallIntegerField(
+                        default=1,
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(1024),
+                        ]
+                    ),
+                ),
+                (
+                    'device',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.device',
+                        related_name='port_mappings'
+                    )
+                ),
+                (
+                    'front_port',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.frontport',
+                        related_name='mappings'
+                    )
+                ),
+                (
+                    'rear_port',
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to='dcim.rearport',
+                        related_name='mappings'
+                    )
+                ),
+            ],
+        ),
+        migrations.AddConstraint(
+            model_name='portmapping',
+            constraint=models.UniqueConstraint(
+                fields=('front_port', 'front_port_position'),
+                name='dcim_portmapping_unique_front_port_position'
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name='portmapping',
+            constraint=models.UniqueConstraint(
+                fields=('rear_port', 'rear_port_position'),
+                name='dcim_portmapping_unique_rear_port_position'
+            ),
+        ),
+
+        # Data migration
+        migrations.RunPython(
+            code=populate_port_template_mappings,
+            reverse_code=migrations.RunPython.noop
+        ),
+        migrations.RunPython(
+            code=populate_port_mappings,
+            reverse_code=migrations.RunPython.noop
+        ),
+    ]

netbox/dcim/migrations/0223_frontport_positions.py

@@ -0,0 +1,65 @@
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('dcim', '0222_port_mappings'),
+    ]
+
+    operations = [
+        # Remove rear_port & rear_port_position from FrontPortTemplate
+        migrations.RemoveConstraint(
+            model_name='frontporttemplate',
+            name='dcim_frontporttemplate_unique_rear_port_position',
+        ),
+        migrations.RemoveField(
+            model_name='frontporttemplate',
+            name='rear_port',
+        ),
+        migrations.RemoveField(
+            model_name='frontporttemplate',
+            name='rear_port_position',
+        ),
+
+        # Add positions on FrontPortTemplate
+        migrations.AddField(
+            model_name='frontporttemplate',
+            name='positions',
+            field=models.PositiveSmallIntegerField(
+                default=1,
+                validators=[
+                    django.core.validators.MinValueValidator(1),
+                    django.core.validators.MaxValueValidator(1024)
+                ]
+            ),
+        ),
+
+        # Remove rear_port & rear_port_position from FrontPort
+        migrations.RemoveConstraint(
+            model_name='frontport',
+            name='dcim_frontport_unique_rear_port_position',
+        ),
+        migrations.RemoveField(
+            model_name='frontport',
+            name='rear_port',
+        ),
+        migrations.RemoveField(
+            model_name='frontport',
+            name='rear_port_position',
+        ),
+
+        # Add positions on FrontPort
+        migrations.AddField(
+            model_name='frontport',
+            name='positions',
+            field=models.PositiveSmallIntegerField(
+                default=1,
+                validators=[
+                    django.core.validators.MinValueValidator(1),
+                    django.core.validators.MaxValueValidator(1024)
+                ]
+            ),
+        ),
+    ]

netbox/dcim/models/base.py

@@ -0,0 +1,61 @@
+from django.core.exceptions import ValidationError
+from django.core.validators import MaxValueValidator, MinValueValidator
+from django.db import models
+from django.utils.translation import gettext_lazy as _
+
+from dcim.constants import PORT_POSITION_MAX, PORT_POSITION_MIN
+
+__all__ = (
+    'PortMappingBase',
+)
+
+
+class PortMappingBase(models.Model):
+    """
+    Base class for PortMapping and PortTemplateMapping
+    """
+    front_port_position = models.PositiveSmallIntegerField(
+        default=1,
+        validators=(
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX),
+        ),
+    )
+    rear_port_position = models.PositiveSmallIntegerField(
+        default=1,
+        validators=(
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX),
+        ),
+    )
+
+    _netbox_private = True
+
+    class Meta:
+        abstract = True
+        constraints = (
+            models.UniqueConstraint(
+                fields=('front_port', 'front_port_position'),
+                name='%(app_label)s_%(class)s_unique_front_port_position'
+            ),
+            models.UniqueConstraint(
+                fields=('rear_port', 'rear_port_position'),
+                name='%(app_label)s_%(class)s_unique_rear_port_position'
+            ),
+        )
+
+    def clean(self):
+        super().clean()
+
+        # Validate rear port position
+        if self.rear_port_position > self.rear_port.positions:
+            raise ValidationError({
+                "rear_port_position": _(
+                    "Invalid rear port position ({rear_port_position}): Rear port {name} has only {positions} "
+                    "positions."
+                ).format(
+                    rear_port_position=self.rear_port_position,
+                    name=self.rear_port.name,
+                    positions=self.rear_port.positions
+                )
+            })

netbox/dcim/models/cables.py

@@ -1,4 +1,5 @@
 import itertools
+import logging
 
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
@@ -22,7 +23,7 @@ from utilities.fields import ColorField, GenericArrayForeignKey
 from utilities.querysets import RestrictedQuerySet
 from utilities.serialization import deserialize_object, serialize_object
 from wireless.models import WirelessLink
-from .device_components import FrontPort, PathEndpoint, RearPort
+from .device_components import FrontPort, PathEndpoint, PortMapping, RearPort
 
 __all__ = (
     'Cable',
@@ -30,6 +31,8 @@ __all__ = (
     'CableTermination',
 )
 
+logger = logging.getLogger(f'netbox.{__name__}')
+
 trace_paths = Signal()
 
 
@@ -666,7 +669,13 @@ class CablePath(models.Model):
         is_active = True
         is_split = False
 
+        logger.debug(f'Tracing cable path from {terminations}...')
+
+        segment = 0
         while terminations:
+            segment += 1
+            logger.debug(f'[Path segment #{segment}] Position stack: {position_stack}')
+            logger.debug(f'[Path segment #{segment}] Local terminations: {terminations}')
 
             # Terminations must all be of the same type
             if not all(isinstance(t, type(terminations[0])) for t in terminations[1:]):
@@ -697,7 +706,10 @@ class CablePath(models.Model):
                 position_stack.append([terminations[0].cable_position])
 
             # Step 2: Determine the attached links (Cable or WirelessLink), if any
-            links = [termination.link for termination in terminations if termination.link is not None]
+            links = list(dict.fromkeys(
+                termination.link for termination in terminations if termination.link is not None
+            ))
+            logger.debug(f'[Path segment #{segment}] Links: {links}')
             if len(links) == 0:
                 if len(path) == 1:
                     # If this is the start of the path and no link exists, return None
@@ -760,10 +772,13 @@ class CablePath(models.Model):
                     link.interface_b if link.interface_a is terminations[0] else link.interface_a for link in links
                 ]
 
+            logger.debug(f'[Path segment #{segment}] Remote terminations: {remote_terminations}')
+
             # Remote Terminations must all be of the same type, otherwise return a split path
             if not all(isinstance(t, type(remote_terminations[0])) for t in remote_terminations[1:]):
                 is_complete = False
                 is_split = True
+                logger.debug('Remote termination types differ; aborting trace.')
                 break
 
             # Step 7: Record the far-end termination object(s)
@@ -777,58 +792,53 @@ class CablePath(models.Model):
 
             if isinstance(remote_terminations[0], FrontPort):
                 # Follow FrontPorts to their corresponding RearPorts
-                rear_ports = RearPort.objects.filter(
-                    pk__in=[t.rear_port_id for t in remote_terminations]
-                )
-                if len(rear_ports) > 1 or rear_ports[0].positions > 1:
-                    position_stack.append([fp.rear_port_position for fp in remote_terminations])
+                if remote_terminations[0].positions > 1 and position_stack:
+                    positions = position_stack.pop()
+                    q_filter = Q()
+                    for rt in remote_terminations:
+                        q_filter |= Q(front_port=rt, front_port_position__in=positions)
+                    port_mappings = PortMapping.objects.filter(q_filter)
+                elif remote_terminations[0].positions > 1:
+                    is_split = True
+                    logger.debug(
+                        'Encountered front port mapped to multiple rear ports but position stack is empty; aborting '
+                        'trace.'
+                    )
+                    break
+                else:
+                    port_mappings = PortMapping.objects.filter(front_port__in=remote_terminations)
+                if not port_mappings:
+                    break
 
-                terminations = rear_ports
+                # Compile the list of RearPorts without duplication or altering their ordering
+                terminations = list(dict.fromkeys(mapping.rear_port for mapping in port_mappings))
+                if any(t.positions > 1 for t in terminations):
+                    position_stack.append([mapping.rear_port_position for mapping in port_mappings])
 
             elif isinstance(remote_terminations[0], RearPort):
-                if len(remote_terminations) == 1 and remote_terminations[0].positions == 1:
-                    front_ports = FrontPort.objects.filter(
-                        rear_port_id__in=[rp.pk for rp in remote_terminations],
-                        rear_port_position=1
-                    )
-                # Obtain the individual front ports based on the termination and all positions
-                elif len(remote_terminations) > 1 and position_stack:
+                # Follow RearPorts to their corresponding FrontPorts
+                if remote_terminations[0].positions > 1 and position_stack:
                     positions = position_stack.pop()
-
-                    # Ensure we have a number of positions equal to the amount of remote terminations
-                    if len(remote_terminations) != len(positions):
-                        raise UnsupportedCablePath(
-                            _("All positions counts within the path on opposite ends of links must match")
-                        )
-
-                    # Get our front ports
                     q_filter = Q()
                     for rt in remote_terminations:
-                        position = positions.pop()
-                        q_filter |= Q(rear_port_id=rt.pk, rear_port_position=position)
-                    if q_filter is Q():
-                        raise UnsupportedCablePath(_("Remote termination position filter is missing"))
-                    front_ports = FrontPort.objects.filter(q_filter)
-                # Obtain the individual front ports based on the termination and position
-                elif position_stack:
-                    front_ports = FrontPort.objects.filter(
-                        rear_port_id=remote_terminations[0].pk,
-                        rear_port_position__in=position_stack.pop()
+                        q_filter |= Q(rear_port=rt, rear_port_position__in=positions)
+                    port_mappings = PortMapping.objects.filter(q_filter)
+                elif remote_terminations[0].positions > 1:
+                    is_split = True
+                    logger.debug(
+                        'Encountered rear port mapped to multiple front ports but position stack is empty; aborting '
+                        'trace.'
                     )
-                # If all rear ports have a single position, we can just get the front ports
-                elif all([rp.positions == 1 for rp in remote_terminations]):
-                    front_ports = FrontPort.objects.filter(rear_port_id__in=[rp.pk for rp in remote_terminations])
-
-                    if len(front_ports) != len(remote_terminations):
-                        # Some rear ports does not have a front port
-                        is_split = True
-                        break
+                    break
                 else:
-                    # No position indicated: path has split, so we stop at the RearPorts
-                    is_split = True
+                    port_mappings = PortMapping.objects.filter(rear_port__in=remote_terminations)
+                if not port_mappings:
                     break
 
-                terminations = front_ports
+                # Compile the list of FrontPorts without duplication or altering their ordering
+                terminations = list(dict.fromkeys(mapping.front_port for mapping in port_mappings))
+                if any(t.positions > 1 for t in terminations):
+                    position_stack.append([mapping.front_port_position for mapping in port_mappings])
 
             elif isinstance(remote_terminations[0], CircuitTermination):
                 # Follow a CircuitTermination to its corresponding CircuitTermination (A to Z or vice versa)
@@ -876,6 +886,7 @@ class CablePath(models.Model):
                     # Unsupported topology, mark as split and exit
                     is_complete = False
                     is_split = True
+                    logger.warning('Encountered an unsupported topology; aborting trace.')
                 break
 
         return cls(
@@ -954,16 +965,23 @@ class CablePath(models.Model):
 
         # RearPort splitting to multiple FrontPorts with no stack position
         if type(nodes[0]) is RearPort:
-            return FrontPort.objects.filter(rear_port__in=nodes)
+            return [
+                mapping.front_port for mapping in
+                PortMapping.objects.filter(rear_port__in=nodes).prefetch_related('front_port')
+            ]
         # Cable terminating to multiple FrontPorts mapped to different
         # RearPorts connected to different cables
-        elif type(nodes[0]) is FrontPort:
-            return RearPort.objects.filter(pk__in=[fp.rear_port_id for fp in nodes])
+        if type(nodes[0]) is FrontPort:
+            return [
+                mapping.rear_port for mapping in
+                PortMapping.objects.filter(front_port__in=nodes).prefetch_related('rear_port')
+            ]
         # Cable terminating to multiple CircuitTerminations
-        elif type(nodes[0]) is CircuitTermination:
+        if type(nodes[0]) is CircuitTermination:
             return [
                 ct.get_peer_termination() for ct in nodes
             ]
+        return []
 
     def get_asymmetric_nodes(self):
         """

netbox/dcim/models/device_component_templates.py

@@ -7,6 +7,7 @@ from mptt.models import MPTTModel, TreeForeignKey
 
 from dcim.choices import *
 from dcim.constants import *
+from dcim.models.base import PortMappingBase
 from dcim.models.mixins import InterfaceValidationMixin
 from netbox.models import ChangeLoggedModel
 from utilities.fields import ColorField, NaturalOrderingField
@@ -28,6 +29,7 @@ __all__ = (
     'InterfaceTemplate',
     'InventoryItemTemplate',
     'ModuleBayTemplate',
+    'PortTemplateMapping',
     'PowerOutletTemplate',
     'PowerPortTemplate',
     'RearPortTemplate',
@@ -518,6 +520,53 @@ class InterfaceTemplate(InterfaceValidationMixin, ModularComponentTemplateModel)
         }
 
 
+class PortTemplateMapping(PortMappingBase):
+    """
+    Maps a FrontPortTemplate & position to a RearPortTemplate & position.
+    """
+    device_type = models.ForeignKey(
+        to='dcim.DeviceType',
+        on_delete=models.CASCADE,
+        related_name='port_mappings',
+        blank=True,
+        null=True,
+    )
+    module_type = models.ForeignKey(
+        to='dcim.ModuleType',
+        on_delete=models.CASCADE,
+        related_name='port_mappings',
+        blank=True,
+        null=True,
+    )
+    front_port = models.ForeignKey(
+        to='dcim.FrontPortTemplate',
+        on_delete=models.CASCADE,
+        related_name='mappings',
+    )
+    rear_port = models.ForeignKey(
+        to='dcim.RearPortTemplate',
+        on_delete=models.CASCADE,
+        related_name='mappings',
+    )
+
+    def clean(self):
+        super().clean()
+
+        # Validate rear port assignment
+        if self.front_port.device_type_id != self.rear_port.device_type_id:
+            raise ValidationError({
+                "rear_port": _("Rear port ({rear_port}) must belong to the same device type").format(
+                    rear_port=self.rear_port
+                )
+            })
+
+    def save(self, *args, **kwargs):
+        # Associate the mapping with the parent DeviceType/ModuleType
+        self.device_type = self.front_port.device_type
+        self.module_type = self.front_port.module_type
+        super().save(*args, **kwargs)
+
+
 class FrontPortTemplate(ModularComponentTemplateModel):
     """
     Template for a pass-through port on the front of a new Device.
@@ -531,18 +580,13 @@ class FrontPortTemplate(ModularComponentTemplateModel):
         verbose_name=_('color'),
         blank=True
     )
-    rear_port = models.ForeignKey(
-        to='dcim.RearPortTemplate',
-        on_delete=models.CASCADE,
-        related_name='frontport_templates'
-    )
-    rear_port_position = models.PositiveSmallIntegerField(
-        verbose_name=_('rear port position'),
+    positions = models.PositiveSmallIntegerField(
+        verbose_name=_('positions'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
-        ]
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
+        ],
     )
 
     component_model = FrontPort
@@ -557,10 +601,6 @@ class FrontPortTemplate(ModularComponentTemplateModel):
                 fields=('module_type', 'name'),
                 name='%(app_label)s_%(class)s_unique_module_type_name'
             ),
-            models.UniqueConstraint(
-                fields=('rear_port', 'rear_port_position'),
-                name='%(app_label)s_%(class)s_unique_rear_port_position'
-            ),
         )
         verbose_name = _('front port template')
         verbose_name_plural = _('front port templates')
@@ -568,40 +608,23 @@ class FrontPortTemplate(ModularComponentTemplateModel):
     def clean(self):
         super().clean()
 
-        try:
-
-            # Validate rear port assignment
-            if self.rear_port.device_type != self.device_type:
-                raise ValidationError(
-                    _("Rear port ({name}) must belong to the same device type").format(name=self.rear_port)
-                )
-
-            # Validate rear port position assignment
-            if self.rear_port_position > self.rear_port.positions:
-                raise ValidationError(
-                    _("Invalid rear port position ({position}); rear port {name} has only {count} positions").format(
-                        position=self.rear_port_position,
-                        name=self.rear_port.name,
-                        count=self.rear_port.positions
-                    )
-                )
-
-        except RearPortTemplate.DoesNotExist:
-            pass
+        # Check that positions is greater than or equal to the number of associated RearPortTemplates
+        if not self._state.adding:
+            mapping_count = self.mappings.count()
+            if self.positions < mapping_count:
+                raise ValidationError({
+                    "positions": _(
+                        "The number of positions cannot be less than the number of mapped rear port templates ({count})"
+                    ).format(count=mapping_count)
+                })
 
     def instantiate(self, **kwargs):
-        if self.rear_port:
-            rear_port_name = self.rear_port.resolve_name(kwargs.get('module'))
-            rear_port = RearPort.objects.get(name=rear_port_name, **kwargs)
-        else:
-            rear_port = None
         return self.component_model(
             name=self.resolve_name(kwargs.get('module')),
             label=self.resolve_label(kwargs.get('module')),
             type=self.type,
             color=self.color,
-            rear_port=rear_port,
-            rear_port_position=self.rear_port_position,
+            positions=self.positions,
             **kwargs
         )
     instantiate.do_not_call_in_templates = True
@@ -611,8 +634,7 @@ class FrontPortTemplate(ModularComponentTemplateModel):
             'name': self.name,
             'type': self.type,
             'color': self.color,
-            'rear_port': self.rear_port.name,
-            'rear_port_position': self.rear_port_position,
+            'positions': self.positions,
             'label': self.label,
             'description': self.description,
         }
@@ -635,9 +657,9 @@ class RearPortTemplate(ModularComponentTemplateModel):
         verbose_name=_('positions'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
-        ]
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
+        ],
     )
 
     component_model = RearPort
@@ -646,6 +668,20 @@ class RearPortTemplate(ModularComponentTemplateModel):
         verbose_name = _('rear port template')
         verbose_name_plural = _('rear port templates')
 
+    def clean(self):
+        super().clean()
+
+        # Check that positions is greater than or equal to the number of associated FrontPortTemplates
+        if not self._state.adding:
+            mapping_count = self.mappings.count()
+            if self.positions < mapping_count:
+                raise ValidationError({
+                    "positions": _(
+                        "The number of positions cannot be less than the number of mapped front port templates "
+                        "({count})"
+                    ).format(count=mapping_count)
+                })
+
     def instantiate(self, **kwargs):
         return self.component_model(
             name=self.resolve_name(kwargs.get('module')),

netbox/dcim/models/device_components.py

@@ -11,6 +11,7 @@ from mptt.models import MPTTModel, TreeForeignKey
 from dcim.choices import *
 from dcim.constants import *
 from dcim.fields import WWNField
+from dcim.models.base import PortMappingBase
 from dcim.models.mixins import InterfaceValidationMixin
 from netbox.choices import ColorChoices
 from netbox.models import OrganizationalModel, NetBoxModel
@@ -35,6 +36,7 @@ __all__ = (
     'InventoryItemRole',
     'ModuleBay',
     'PathEndpoint',
+    'PortMapping',
     'PowerOutlet',
     'PowerPort',
     'RearPort',
@@ -208,10 +210,6 @@ class CabledObjectModel(models.Model):
                 raise ValidationError({
                     "cable_end": _("Must specify cable end (A or B) when attaching a cable.")
                 })
-            if not self.cable_position:
-                raise ValidationError({
-                    "cable_position": _("Must specify cable termination position when attaching a cable.")
-                })
         if self.cable_end and not self.cable:
             raise ValidationError({
                 "cable_end": _("Cable end must not be set without a cable.")
@@ -1069,6 +1067,43 @@ class Interface(
 # Pass-through ports
 #
 
+class PortMapping(PortMappingBase):
+    """
+    Maps a FrontPort & position to a RearPort & position.
+    """
+    device = models.ForeignKey(
+        to='dcim.Device',
+        on_delete=models.CASCADE,
+        related_name='port_mappings',
+    )
+    front_port = models.ForeignKey(
+        to='dcim.FrontPort',
+        on_delete=models.CASCADE,
+        related_name='mappings',
+    )
+    rear_port = models.ForeignKey(
+        to='dcim.RearPort',
+        on_delete=models.CASCADE,
+        related_name='mappings',
+    )
+
+    def clean(self):
+        super().clean()
+
+        # Both ports must belong to the same device
+        if self.front_port.device_id != self.rear_port.device_id:
+            raise ValidationError({
+                "rear_port": _("Rear port ({rear_port}) must belong to the same device").format(
+                    rear_port=self.rear_port
+                )
+            })
+
+    def save(self, *args, **kwargs):
+        # Associate the mapping with the parent Device
+        self.device = self.front_port.device
+        super().save(*args, **kwargs)
+
+
 class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
     """
     A pass-through port on the front of a Device.
@@ -1082,22 +1117,16 @@ class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
         verbose_name=_('color'),
         blank=True
     )
-    rear_port = models.ForeignKey(
-        to='dcim.RearPort',
-        on_delete=models.CASCADE,
-        related_name='frontports'
-    )
-    rear_port_position = models.PositiveSmallIntegerField(
-        verbose_name=_('rear port position'),
+    positions = models.PositiveSmallIntegerField(
+        verbose_name=_('positions'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
         ],
-        help_text=_('Mapped position on corresponding rear port')
     )
 
-    clone_fields = ('device', 'type', 'color')
+    clone_fields = ('device', 'type', 'color', 'positions')
 
     class Meta(ModularComponentModel.Meta):
         constraints = (
@@ -1105,10 +1134,6 @@ class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
                 fields=('device', 'name'),
                 name='%(app_label)s_%(class)s_unique_device_name'
             ),
-            models.UniqueConstraint(
-                fields=('rear_port', 'rear_port_position'),
-                name='%(app_label)s_%(class)s_unique_rear_port_position'
-            ),
         )
         verbose_name = _('front port')
         verbose_name_plural = _('front ports')
@@ -1116,27 +1141,14 @@ class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
     def clean(self):
         super().clean()
 
-        if hasattr(self, 'rear_port'):
-
-            # Validate rear port assignment
-            if self.rear_port.device != self.device:
-                raise ValidationError({
-                    "rear_port": _(
-                        "Rear port ({rear_port}) must belong to the same device"
-                    ).format(rear_port=self.rear_port)
-                })
-
-            # Validate rear port position assignment
-            if self.rear_port_position > self.rear_port.positions:
+        # Check that positions is greater than or equal to the number of associated RearPorts
+        if not self._state.adding:
+            mapping_count = self.mappings.count()
+            if self.positions < mapping_count:
                 raise ValidationError({
-                    "rear_port_position": _(
-                        "Invalid rear port position ({rear_port_position}): Rear port {name} has only {positions} "
-                        "positions."
-                    ).format(
-                        rear_port_position=self.rear_port_position,
-                        name=self.rear_port.name,
-                        positions=self.rear_port.positions
-                    )
+                    "positions": _(
+                        "The number of positions cannot be less than the number of mapped rear ports ({count})"
+                    ).format(count=mapping_count)
                 })
 
 
@@ -1157,11 +1169,11 @@ class RearPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
         verbose_name=_('positions'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
         ],
-        help_text=_('Number of front ports which may be mapped')
     )
+
     clone_fields = ('device', 'type', 'color', 'positions')
 
     class Meta(ModularComponentModel.Meta):
@@ -1173,13 +1185,13 @@ class RearPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
 
         # Check that positions count is greater than or equal to the number of associated FrontPorts
         if not self._state.adding:
-            frontport_count = self.frontports.count()
-            if self.positions < frontport_count:
+            mapping_count = self.mappings.count()
+            if self.positions < mapping_count:
                 raise ValidationError({
                     "positions": _(
                         "The number of positions cannot be less than the number of mapped front ports "
-                        "({frontport_count})"
-                    ).format(frontport_count=frontport_count)
+                        "({count})"
+                    ).format(count=mapping_count)
                 })
 
 

netbox/dcim/models/devices.py

@@ -1,8 +1,7 @@
 import decimal
-import yaml
-
 from functools import cached_property
 
+import yaml
 from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ValidationError
@@ -19,14 +18,14 @@ from django.utils.translation import gettext_lazy as _
 from dcim.choices import *
 from dcim.constants import *
 from dcim.fields import MACAddressField
-from dcim.utils import update_interface_bridges
+from dcim.utils import create_port_mappings, update_interface_bridges
 from extras.models import ConfigContextModel, CustomField
 from extras.querysets import ConfigContextModelQuerySet
 from netbox.choices import ColorChoices
 from netbox.config import ConfigItem
 from netbox.models import NestedGroupModel, OrganizationalModel, PrimaryModel
-from netbox.models.mixins import WeightMixin
 from netbox.models.features import ContactsMixin, ImageAttachmentsMixin
+from netbox.models.mixins import WeightMixin
 from utilities.fields import ColorField, CounterCacheField
 from utilities.prefetch import get_prefetchable_fields
 from utilities.tracking import TrackingModelMixin
@@ -34,7 +33,6 @@ from .device_components import *
 from .mixins import RenderConfigMixin
 from .modules import Module
 
-
 __all__ = (
     'Device',
     'DeviceRole',
@@ -1009,6 +1007,8 @@ class Device(
             self._instantiate_components(self.device_type.interfacetemplates.all())
             self._instantiate_components(self.device_type.rearporttemplates.all())
             self._instantiate_components(self.device_type.frontporttemplates.all())
+            # Replicate any front/rear port mappings from the DeviceType
+            create_port_mappings(self, self.device_type)
             # Disable bulk_create to accommodate MPTT
             self._instantiate_components(self.device_type.modulebaytemplates.all(), bulk_create=False)
             self._instantiate_components(self.device_type.devicebaytemplates.all())

netbox/dcim/signals.py

@@ -1,5 +1,6 @@
 import logging
 
+from django.db.models import Q
 from django.db.models.signals import post_save, post_delete
 from django.dispatch import receiver
 
@@ -7,7 +8,7 @@ from dcim.choices import CableEndChoices, LinkStatusChoices
 from virtualization.models import VMInterface
 from .models import (
     Cable, CablePath, CableTermination, ConsolePort, ConsoleServerPort, Device, DeviceBay, FrontPort, Interface,
-    InventoryItem, ModuleBay, PathEndpoint, PowerOutlet, PowerPanel, PowerPort, Rack, RearPort, Location,
+    InventoryItem, ModuleBay, PathEndpoint, PortMapping, PowerOutlet, PowerPanel, PowerPort, Rack, RearPort, Location,
     VirtualChassis,
 )
 from .models.cables import trace_paths
@@ -135,6 +136,17 @@ def retrace_cable_paths(instance, **kwargs):
         cablepath.retrace()
 
 
+@receiver((post_delete, post_save), sender=PortMapping)
+def update_passthrough_port_paths(instance, **kwargs):
+    """
+    When a PortMapping is created or deleted, retrace any CablePaths which traverse its front and/or rear ports.
+    """
+    for cablepath in CablePath.objects.filter(
+        Q(_nodes__contains=instance.front_port) | Q(_nodes__contains=instance.rear_port)
+    ):
+        cablepath.retrace()
+
+
 @receiver(post_delete, sender=CableTermination)
 def nullify_connected_endpoints(instance, **kwargs):
     """
@@ -150,17 +162,6 @@ def nullify_connected_endpoints(instance, **kwargs):
         cablepath.retrace()
 
 
-@receiver(post_save, sender=FrontPort)
-def extend_rearport_cable_paths(instance, created, raw, **kwargs):
-    """
-    When a new FrontPort is created, add it to any CablePaths which end at its corresponding RearPort.
-    """
-    if created and not raw:
-        rearport = instance.rear_port
-        for cablepath in CablePath.objects.filter(_nodes__contains=rearport):
-            cablepath.retrace()
-
-
 @receiver(post_save, sender=Interface)
 @receiver(post_save, sender=VMInterface)
 def update_mac_address_interface(instance, created, raw, **kwargs):

netbox/dcim/tables/devices.py

@@ -749,12 +749,9 @@ class FrontPortTable(ModularDeviceComponentTable, CableTerminationTable):
     color = columns.ColorColumn(
         verbose_name=_('Color'),
     )
-    rear_port_position = tables.Column(
-        verbose_name=_('Position')
-    )
-    rear_port = tables.Column(
-        verbose_name=_('Rear Port'),
-        linkify=True
+    mappings = columns.ManyToManyColumn(
+        verbose_name=_('Mappings'),
+        transform=lambda obj: f'{obj.rear_port}:{obj.rear_port_position}'
     )
     tags = columns.TagColumn(
         url_name='dcim:frontport_list'
@@ -763,12 +760,12 @@ class FrontPortTable(ModularDeviceComponentTable, CableTerminationTable):
     class Meta(DeviceComponentTable.Meta):
         model = models.FrontPort
         fields = (
-            'pk', 'id', 'name', 'device', 'module_bay', 'module', 'label', 'type', 'color', 'rear_port',
-            'rear_port_position', 'description', 'mark_connected', 'cable', 'cable_color', 'link_peer',
-            'inventory_items', 'tags', 'created', 'last_updated',
+            'pk', 'id', 'name', 'device', 'module_bay', 'module', 'label', 'type', 'color', 'positions', 'mappings',
+            'description', 'mark_connected', 'cable', 'cable_color', 'link_peer', 'inventory_items', 'tags', 'created',
+            'last_updated',
         )
         default_columns = (
-            'pk', 'name', 'device', 'label', 'type', 'color', 'rear_port', 'rear_port_position', 'description',
+            'pk', 'name', 'device', 'label', 'type', 'color', 'positions', 'mappings', 'description',
         )
 
 
@@ -786,11 +783,11 @@ class DeviceFrontPortTable(FrontPortTable):
     class Meta(CableTerminationTable.Meta, DeviceComponentTable.Meta):
         model = models.FrontPort
         fields = (
-            'pk', 'id', 'name', 'module_bay', 'module', 'label', 'type', 'rear_port', 'rear_port_position',
+            'pk', 'id', 'name', 'module_bay', 'module', 'label', 'type', 'color', 'positions', 'mappings',
             'description', 'mark_connected', 'cable', 'cable_color', 'link_peer', 'tags', 'actions',
         )
         default_columns = (
-            'pk', 'name', 'label', 'type', 'rear_port', 'rear_port_position', 'description', 'cable', 'link_peer',
+            'pk', 'name', 'label', 'type', 'color', 'positions', 'mappings', 'description', 'cable', 'link_peer',
         )
 
 
@@ -805,6 +802,10 @@ class RearPortTable(ModularDeviceComponentTable, CableTerminationTable):
     color = columns.ColorColumn(
         verbose_name=_('Color'),
     )
+    mappings = columns.ManyToManyColumn(
+        verbose_name=_('Mappings'),
+        transform=lambda obj: f'{obj.front_port}:{obj.front_port_position}'
+    )
     tags = columns.TagColumn(
         url_name='dcim:rearport_list'
     )
@@ -812,10 +813,13 @@ class RearPortTable(ModularDeviceComponentTable, CableTerminationTable):
     class Meta(DeviceComponentTable.Meta):
         model = models.RearPort
         fields = (
-            'pk', 'id', 'name', 'device', 'module_bay', 'module', 'label', 'type', 'color', 'positions', 'description',
-            'mark_connected', 'cable', 'cable_color', 'link_peer', 'inventory_items', 'tags', 'created', 'last_updated',
+            'pk', 'id', 'name', 'device', 'module_bay', 'module', 'label', 'type', 'color', 'positions', 'mappings',
+            'description', 'mark_connected', 'cable', 'cable_color', 'link_peer', 'inventory_items', 'tags', 'created',
+            'last_updated',
+        )
+        default_columns = (
+            'pk', 'name', 'device', 'label', 'type', 'color', 'positions', 'mappings', 'description',
         )
-        default_columns = ('pk', 'name', 'device', 'label', 'type', 'color', 'description')
 
 
 class DeviceRearPortTable(RearPortTable):
@@ -832,11 +836,11 @@ class DeviceRearPortTable(RearPortTable):
     class Meta(CableTerminationTable.Meta, DeviceComponentTable.Meta):
         model = models.RearPort
         fields = (
-            'pk', 'id', 'name', 'module_bay', 'module', 'label', 'type', 'positions', 'description', 'mark_connected',
-            'cable', 'cable_color', 'link_peer', 'tags', 'actions',
+            'pk', 'id', 'name', 'module_bay', 'module', 'label', 'type', 'color', 'positions', 'mappings',
+            'description', 'mark_connected', 'cable', 'cable_color', 'link_peer', 'tags', 'actions',
         )
         default_columns = (
-            'pk', 'name', 'label', 'type', 'positions', 'description', 'cable', 'link_peer',
+            'pk', 'name', 'label', 'type', 'color', 'positions', 'mappings', 'description', 'cable', 'link_peer',
         )
 
 

netbox/dcim/tables/devicetypes.py

@@ -249,12 +249,13 @@ class InterfaceTemplateTable(ComponentTemplateTable):
 
 
 class FrontPortTemplateTable(ComponentTemplateTable):
-    rear_port_position = tables.Column(
-        verbose_name=_('Position')
-    )
     color = columns.ColorColumn(
         verbose_name=_('Color'),
     )
+    mappings = columns.ManyToManyColumn(
+        verbose_name=_('Mappings'),
+        transform=lambda obj: f'{obj.rear_port}:{obj.rear_port_position}'
+    )
     actions = columns.ActionsColumn(
         actions=('edit', 'delete'),
         extra_buttons=MODULAR_COMPONENT_TEMPLATE_BUTTONS
@@ -262,7 +263,7 @@ class FrontPortTemplateTable(ComponentTemplateTable):
 
     class Meta(ComponentTemplateTable.Meta):
         model = models.FrontPortTemplate
-        fields = ('pk', 'name', 'label', 'type', 'color', 'rear_port', 'rear_port_position', 'description', 'actions')
+        fields = ('pk', 'name', 'label', 'type', 'color', 'positions', 'mappings', 'description', 'actions')
         empty_text = "None"
 
 
@@ -270,6 +271,10 @@ class RearPortTemplateTable(ComponentTemplateTable):
     color = columns.ColorColumn(
         verbose_name=_('Color'),
     )
+    mappings = columns.ManyToManyColumn(
+        verbose_name=_('Mappings'),
+        transform=lambda obj: f'{obj.front_port}:{obj.front_port_position}'
+    )
     actions = columns.ActionsColumn(
         actions=('edit', 'delete'),
         extra_buttons=MODULAR_COMPONENT_TEMPLATE_BUTTONS
@@ -277,7 +282,7 @@ class RearPortTemplateTable(ComponentTemplateTable):
 
     class Meta(ComponentTemplateTable.Meta):
         model = models.RearPortTemplate
-        fields = ('pk', 'name', 'label', 'type', 'color', 'positions', 'description', 'actions')
+        fields = ('pk', 'name', 'label', 'type', 'color', 'positions', 'mappings', 'description', 'actions')
         empty_text = "None"
 
 

netbox/dcim/tests/test_api.py

@@ -973,72 +973,99 @@ class FrontPortTemplateTest(APIViewTestCases.APIViewTestCase):
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 2', type=PortTypeChoices.TYPE_8P8C),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 3', type=PortTypeChoices.TYPE_8P8C),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 4', type=PortTypeChoices.TYPE_8P8C),
-            RearPortTemplate(module_type=moduletype, name='Rear Port Template 5', type=PortTypeChoices.TYPE_8P8C),
-            RearPortTemplate(module_type=moduletype, name='Rear Port Template 6', type=PortTypeChoices.TYPE_8P8C),
-            RearPortTemplate(module_type=moduletype, name='Rear Port Template 7', type=PortTypeChoices.TYPE_8P8C),
-            RearPortTemplate(module_type=moduletype, name='Rear Port Template 8', type=PortTypeChoices.TYPE_8P8C),
+            RearPortTemplate(device_type=devicetype, name='Rear Port Template 5', type=PortTypeChoices.TYPE_8P8C),
+            RearPortTemplate(device_type=devicetype, name='Rear Port Template 6', type=PortTypeChoices.TYPE_8P8C),
         )
         RearPortTemplate.objects.bulk_create(rear_port_templates)
-
         front_port_templates = (
-            FrontPortTemplate(
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 2', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(module_type=moduletype, name='Front Port Template 3', type=PortTypeChoices.TYPE_8P8C),
+        )
+        FrontPortTemplate.objects.bulk_create(front_port_templates)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(
                 device_type=devicetype,
-                name='Front Port Template 1',
-                type=PortTypeChoices.TYPE_8P8C,
-                rear_port=rear_port_templates[0]
+                front_port=front_port_templates[0],
+                rear_port=rear_port_templates[0],
             ),
-            FrontPortTemplate(
+            PortTemplateMapping(
                 device_type=devicetype,
-                name='Front Port Template 2',
-                type=PortTypeChoices.TYPE_8P8C,
-                rear_port=rear_port_templates[1]
-            ),
-            FrontPortTemplate(
-                module_type=moduletype,
-                name='Front Port Template 5',
-                type=PortTypeChoices.TYPE_8P8C,
-                rear_port=rear_port_templates[4]
+                front_port=front_port_templates[1],
+                rear_port=rear_port_templates[1],
             ),
-            FrontPortTemplate(
+            PortTemplateMapping(
                 module_type=moduletype,
-                name='Front Port Template 6',
-                type=PortTypeChoices.TYPE_8P8C,
-                rear_port=rear_port_templates[5]
+                front_port=front_port_templates[2],
+                rear_port=rear_port_templates[2],
             ),
-        )
-        FrontPortTemplate.objects.bulk_create(front_port_templates)
+        ])
 
         cls.create_data = [
             {
                 'device_type': devicetype.pk,
                 'name': 'Front Port Template 3',
                 'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_port_templates[2].pk,
-                'rear_port_position': 1,
+                'rear_ports': [
+                    {
+                        'position': 1,
+                        'rear_port': rear_port_templates[3].pk,
+                        'rear_port_position': 1,
+                    },
+                ],
             },
             {
                 'device_type': devicetype.pk,
                 'name': 'Front Port Template 4',
                 'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_port_templates[3].pk,
-                'rear_port_position': 1,
+                'rear_ports': [
+                    {
+                        'position': 1,
+                        'rear_port': rear_port_templates[4].pk,
+                        'rear_port_position': 1,
+                    },
+                ],
             },
             {
                 'module_type': moduletype.pk,
                 'name': 'Front Port Template 7',
                 'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_port_templates[6].pk,
-                'rear_port_position': 1,
-            },
-            {
-                'module_type': moduletype.pk,
-                'name': 'Front Port Template 8',
-                'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_port_templates[7].pk,
-                'rear_port_position': 1,
+                'rear_ports': [
+                    {
+                        'position': 1,
+                        'rear_port': rear_port_templates[5].pk,
+                        'rear_port_position': 1,
+                    },
+                ],
             },
         ]
 
+        cls.update_data = {
+            'type': PortTypeChoices.TYPE_LC,
+            'rear_ports': [
+                {
+                    'position': 1,
+                    'rear_port': rear_port_templates[3].pk,
+                    'rear_port_position': 1,
+                },
+            ],
+        }
+
+    def test_update_object(self):
+        super().test_update_object()
+
+        # Check that the port mapping was updated after modifying the front port template
+        front_port_template = FrontPortTemplate.objects.get(name='Front Port Template 1')
+        rear_port_template = RearPortTemplate.objects.get(name='Rear Port Template 4')
+        self.assertTrue(
+            PortTemplateMapping.objects.filter(
+                front_port=front_port_template,
+                front_port_position=1,
+                rear_port=rear_port_template,
+                rear_port_position=1,
+            ).exists()
+        )
+
 
 class RearPortTemplateTest(APIViewTestCases.APIViewTestCase):
     model = RearPortTemplate
@@ -1057,36 +1084,104 @@ class RearPortTemplateTest(APIViewTestCases.APIViewTestCase):
             manufacturer=manufacturer, model='Module Type 1'
         )
 
+        front_port_templates = (
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 2', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(module_type=moduletype, name='Front Port Template 3', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(module_type=moduletype, name='Front Port Template 4', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(module_type=moduletype, name='Front Port Template 5', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(module_type=moduletype, name='Front Port Template 6', type=PortTypeChoices.TYPE_8P8C),
+        )
+        FrontPortTemplate.objects.bulk_create(front_port_templates)
         rear_port_templates = (
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 1', type=PortTypeChoices.TYPE_8P8C),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 2', type=PortTypeChoices.TYPE_8P8C),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 3', type=PortTypeChoices.TYPE_8P8C),
         )
         RearPortTemplate.objects.bulk_create(rear_port_templates)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(
+                device_type=devicetype,
+                front_port=front_port_templates[0],
+                rear_port=rear_port_templates[0],
+            ),
+            PortTemplateMapping(
+                device_type=devicetype,
+                front_port=front_port_templates[1],
+                rear_port=rear_port_templates[1],
+            ),
+            PortTemplateMapping(
+                module_type=moduletype,
+                front_port=front_port_templates[2],
+                rear_port=rear_port_templates[2],
+            ),
+        ])
 
         cls.create_data = [
             {
                 'device_type': devicetype.pk,
                 'name': 'Rear Port Template 4',
                 'type': PortTypeChoices.TYPE_8P8C,
+                'front_ports': [
+                    {
+                        'position': 1,
+                        'front_port': front_port_templates[3].pk,
+                        'front_port_position': 1,
+                    },
+                ],
             },
             {
                 'device_type': devicetype.pk,
                 'name': 'Rear Port Template 5',
                 'type': PortTypeChoices.TYPE_8P8C,
+                'front_ports': [
+                    {
+                        'position': 1,
+                        'front_port': front_port_templates[4].pk,
+                        'front_port_position': 1,
+                    },
+                ],
             },
             {
                 'module_type': moduletype.pk,
                 'name': 'Rear Port Template 6',
                 'type': PortTypeChoices.TYPE_8P8C,
-            },
-            {
-                'module_type': moduletype.pk,
-                'name': 'Rear Port Template 7',
-                'type': PortTypeChoices.TYPE_8P8C,
+                'front_ports': [
+                    {
+                        'position': 1,
+                        'front_port': front_port_templates[5].pk,
+                        'front_port_position': 1,
+                    },
+                ],
             },
         ]
 
+        cls.update_data = {
+            'type': PortTypeChoices.TYPE_LC,
+            'front_ports': [
+                {
+                    'position': 1,
+                    'front_port': front_port_templates[3].pk,
+                    'front_port_position': 1,
+                },
+            ],
+        }
+
+    def test_update_object(self):
+        super().test_update_object()
+
+        # Check that the port mapping was updated after modifying the rear port template
+        front_port_template = FrontPortTemplate.objects.get(name='Front Port Template 4')
+        rear_port_template = RearPortTemplate.objects.get(name='Rear Port Template 1')
+        self.assertTrue(
+            PortTemplateMapping.objects.filter(
+                front_port=front_port_template,
+                front_port_position=1,
+                rear_port=rear_port_template,
+                rear_port_position=1,
+            ).exists()
+        )
+
 
 class ModuleBayTemplateTest(APIViewTestCases.APIViewTestCase):
     model = ModuleBayTemplate
@@ -2015,51 +2110,90 @@ class FrontPortTest(APIViewTestCases.APIViewTestCase):
             RearPort(device=device, name='Rear Port 6', type=PortTypeChoices.TYPE_8P8C),
         )
         RearPort.objects.bulk_create(rear_ports)
-
         front_ports = (
-            FrontPort(device=device, name='Front Port 1', type=PortTypeChoices.TYPE_8P8C, rear_port=rear_ports[0]),
-            FrontPort(device=device, name='Front Port 2', type=PortTypeChoices.TYPE_8P8C, rear_port=rear_ports[1]),
-            FrontPort(device=device, name='Front Port 3', type=PortTypeChoices.TYPE_8P8C, rear_port=rear_ports[2]),
+            FrontPort(device=device, name='Front Port 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 2', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 3', type=PortTypeChoices.TYPE_8P8C),
         )
         FrontPort.objects.bulk_create(front_ports)
+        PortMapping.objects.bulk_create([
+            PortMapping(device=device, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortMapping(device=device, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortMapping(device=device, front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
         cls.create_data = [
             {
                 'device': device.pk,
                 'name': 'Front Port 4',
                 'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_ports[3].pk,
-                'rear_port_position': 1,
+                'rear_ports': [
+                    {
+                        'position': 1,
+                        'rear_port': rear_ports[3].pk,
+                        'rear_port_position': 1,
+                    },
+                ],
             },
             {
                 'device': device.pk,
                 'name': 'Front Port 5',
                 'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_ports[4].pk,
-                'rear_port_position': 1,
+                'rear_ports': [
+                    {
+                        'position': 1,
+                        'rear_port': rear_ports[4].pk,
+                        'rear_port_position': 1,
+                    },
+                ],
             },
             {
                 'device': device.pk,
                 'name': 'Front Port 6',
                 'type': PortTypeChoices.TYPE_8P8C,
-                'rear_port': rear_ports[5].pk,
-                'rear_port_position': 1,
+                'rear_ports': [
+                    {
+                        'position': 1,
+                        'rear_port': rear_ports[5].pk,
+                        'rear_port_position': 1,
+                    },
+                ],
             },
         ]
 
+        cls.update_data = {
+            'type': PortTypeChoices.TYPE_LC,
+            'rear_ports': [
+                {
+                    'position': 1,
+                    'rear_port': rear_ports[3].pk,
+                    'rear_port_position': 1,
+                },
+            ],
+        }
+
+    def test_update_object(self):
+        super().test_update_object()
+
+        # Check that the port mapping was updated after modifying the front port
+        front_port = FrontPort.objects.get(name='Front Port 1')
+        rear_port = RearPort.objects.get(name='Rear Port 4')
+        self.assertTrue(
+            PortMapping.objects.filter(
+                front_port=front_port,
+                front_port_position=1,
+                rear_port=rear_port,
+                rear_port_position=1,
+            ).exists()
+        )
+
     @tag('regression')  # Issue #18991
     def test_front_port_paths(self):
         device = Device.objects.first()
-        rear_port = RearPort.objects.create(
-            device=device, name='Rear Port 10', type=PortTypeChoices.TYPE_8P8C
-        )
         interface1 = Interface.objects.create(device=device, name='Interface 1')
-        front_port = FrontPort.objects.create(
-            device=device,
-            name='Rear Port 10',
-            type=PortTypeChoices.TYPE_8P8C,
-            rear_port=rear_port,
-        )
+        rear_port = RearPort.objects.create(device=device, name='Rear Port 10', type=PortTypeChoices.TYPE_8P8C)
+        front_port = FrontPort.objects.create(device=device, name='Front Port 10', type=PortTypeChoices.TYPE_8P8C)
+        PortMapping.objects.create(device=device, front_port=front_port, rear_port=rear_port)
         Cable.objects.create(a_terminations=[interface1], b_terminations=[front_port])
 
         self.add_permissions(f'dcim.view_{self.model._meta.model_name}')
@@ -2086,6 +2220,15 @@ class RearPortTest(APIViewTestCases.APIViewTestCase):
         role = DeviceRole.objects.create(name='Test Device Role 1', slug='test-device-role-1', color='ff0000')
         device = Device.objects.create(device_type=devicetype, role=role, name='Device 1', site=site)
 
+        front_ports = (
+            FrontPort(device=device, name='Front Port 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 2', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 3', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 4', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 5', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=device, name='Front Port 6', type=PortTypeChoices.TYPE_8P8C),
+        )
+        FrontPort.objects.bulk_create(front_ports)
         rear_ports = (
             RearPort(device=device, name='Rear Port 1', type=PortTypeChoices.TYPE_8P8C),
             RearPort(device=device, name='Rear Port 2', type=PortTypeChoices.TYPE_8P8C),
@@ -2098,19 +2241,66 @@ class RearPortTest(APIViewTestCases.APIViewTestCase):
                 'device': device.pk,
                 'name': 'Rear Port 4',
                 'type': PortTypeChoices.TYPE_8P8C,
+                'front_ports': [
+                    {
+                        'position': 1,
+                        'front_port': front_ports[3].pk,
+                        'front_port_position': 1,
+                    },
+                ],
             },
             {
                 'device': device.pk,
                 'name': 'Rear Port 5',
                 'type': PortTypeChoices.TYPE_8P8C,
+                'front_ports': [
+                    {
+                        'position': 1,
+                        'front_port': front_ports[4].pk,
+                        'front_port_position': 1,
+                    },
+                ],
             },
             {
                 'device': device.pk,
                 'name': 'Rear Port 6',
                 'type': PortTypeChoices.TYPE_8P8C,
+                'front_ports': [
+                    {
+                        'position': 1,
+                        'front_port': front_ports[5].pk,
+                        'front_port_position': 1,
+                    },
+                ],
             },
         ]
 
+        cls.update_data = {
+            'type': PortTypeChoices.TYPE_LC,
+            'front_ports': [
+                {
+                    'position': 1,
+                    'front_port': front_ports[3].pk,
+                    'front_port_position': 1,
+                },
+            ],
+        }
+
+    def test_update_object(self):
+        super().test_update_object()
+
+        # Check that the port mapping was updated after modifying the rear port
+        front_port = FrontPort.objects.get(name='Front Port 4')
+        rear_port = RearPort.objects.get(name='Rear Port 1')
+        self.assertTrue(
+            PortMapping.objects.filter(
+                front_port=front_port,
+                front_port_position=1,
+                rear_port=rear_port,
+                rear_port_position=1,
+            ).exists()
+        )
+
     @tag('regression')  # Issue #18991
     def test_rear_port_paths(self):
         device = Device.objects.first()

netbox/dcim/tests/test_cablepaths.py

@@ -281,9 +281,14 @@ class LegacyCablePathTests(CablePathTestCase):
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport1,
+            front_port_position=1,
+            rear_port=rearport1,
+            rear_port_position=1
         )
 
         # Create cable 1
@@ -340,9 +345,14 @@ class LegacyCablePathTests(CablePathTestCase):
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport1,
+            front_port_position=1,
+            rear_port=rearport1,
+            rear_port_position=1
         )
 
         # Create cable 1
@@ -403,18 +413,40 @@ class LegacyCablePathTests(CablePathTestCase):
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
         rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport2, rear_port_position=1
-        )
-        frontport2_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport2, rear_port_position=2
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2_1 = FrontPort.objects.create(device=self.device, name='Front Port 2:1')
+        frontport2_2 = FrontPort.objects.create(device=self.device, name='Front Port 2:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_1,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables 1-2
         cable1 = Cable(
@@ -521,18 +553,40 @@ class LegacyCablePathTests(CablePathTestCase):
         interface8 = Interface.objects.create(device=self.device, name='Interface 8')
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
         rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport2, rear_port_position=1
-        )
-        frontport2_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport2, rear_port_position=2
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2_1 = FrontPort.objects.create(device=self.device, name='Front Port 2:1')
+        frontport2_2 = FrontPort.objects.create(device=self.device, name='Front Port 2:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_1,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables 1-2
         cable1 = Cable(
@@ -680,27 +734,59 @@ class LegacyCablePathTests(CablePathTestCase):
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=1)
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3')
         rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3', rear_port=rearport3, rear_port_position=1
-        )
-        frontport4_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4:1', rear_port=rearport4, rear_port_position=1
-        )
-        frontport4_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4:2', rear_port=rearport4, rear_port_position=2
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3 = FrontPort.objects.create(device=self.device, name='Front Port 3')
+        frontport4_1 = FrontPort.objects.create(device=self.device, name='Front Port 4:1')
+        frontport4_2 = FrontPort.objects.create(device=self.device, name='Front Port 4:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4_1,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4_2,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables 1-2, 6-7
         cable1 = Cable(
@@ -801,30 +887,72 @@ class LegacyCablePathTests(CablePathTestCase):
         rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
         rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=4)
         rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport2, rear_port_position=1
-        )
-        frontport2_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport2, rear_port_position=2
-        )
-        frontport3_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3:1', rear_port=rearport3, rear_port_position=1
-        )
-        frontport3_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3:2', rear_port=rearport3, rear_port_position=2
-        )
-        frontport4_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4:1', rear_port=rearport4, rear_port_position=1
-        )
-        frontport4_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4:2', rear_port=rearport4, rear_port_position=2
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2_1 = FrontPort.objects.create(device=self.device, name='Front Port 2:1')
+        frontport2_2 = FrontPort.objects.create(device=self.device, name='Front Port 2:2')
+        frontport3_1 = FrontPort.objects.create(device=self.device, name='Front Port 3:1')
+        frontport3_2 = FrontPort.objects.create(device=self.device, name='Front Port 3:2')
+        frontport4_1 = FrontPort.objects.create(device=self.device, name='Front Port 4:1')
+        frontport4_2 = FrontPort.objects.create(device=self.device, name='Front Port 4:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_1,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3_1,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3_2,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4_1,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4_2,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables 1-3, 6-8
         cable1 = Cable(
@@ -928,23 +1056,50 @@ class LegacyCablePathTests(CablePathTestCase):
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 5', positions=1)
-        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 5', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport3, rear_port_position=1
-        )
-        frontport3_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport3, rear_port_position=2
-        )
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=4)
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3_1 = FrontPort.objects.create(device=self.device, name='Front Port 3:1')
+        frontport3_2 = FrontPort.objects.create(device=self.device, name='Front Port 3:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3_1,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3_2,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables 1-2, 5-6
         cable1 = Cable(
@@ -1032,13 +1187,25 @@ class LegacyCablePathTests(CablePathTestCase):
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=2)
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables 1
         cable1 = Cable(
@@ -1098,10 +1265,11 @@ class LegacyCablePathTests(CablePathTestCase):
         [IF1] --C1-- [FP1] [RP1] --C2-- [RP2]
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        PortMapping.objects.create(
+            front_port=frontport1, front_port_position=1, rear_port=rearport1, rear_port_position=1,
         )
 
         # Create cables
@@ -1413,18 +1581,40 @@ class LegacyCablePathTests(CablePathTestCase):
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
         rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport2, rear_port_position=1
-        )
-        frontport2_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport2, rear_port_position=2
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2_1 = FrontPort.objects.create(device=self.device, name='Front Port 2:1')
+        frontport2_2 = FrontPort.objects.create(device=self.device, name='Front Port 2:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_1,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=2,
+            ),
+        ])
         circuittermination1 = CircuitTermination.objects.create(
             circuit=self.circuit,
             termination=self.site,
@@ -1601,22 +1791,44 @@ class LegacyCablePathTests(CablePathTestCase):
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=1)
-        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3', rear_port=rearport3, rear_port_position=1
-        )
-        frontport4 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4', rear_port=rearport4, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3')
+        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3 = FrontPort.objects.create(device=self.device, name='Front Port 3')
+        frontport4 = FrontPort.objects.create(device=self.device, name='Front Port 4')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+        ])
 
         # Create cables 1-2
         cable1 = Cable(
@@ -1688,30 +1900,72 @@ class LegacyCablePathTests(CablePathTestCase):
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
         rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport1_3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:3', rear_port=rearport1, rear_port_position=3
-        )
-        frontport1_4 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:4', rear_port=rearport1, rear_port_position=4
-        )
-        frontport2_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport2, rear_port_position=1
-        )
-        frontport2_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport2, rear_port_position=2
-        )
-        frontport2_3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:3', rear_port=rearport2, rear_port_position=3
-        )
-        frontport2_4 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:4', rear_port=rearport2, rear_port_position=4
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport1_3 = FrontPort.objects.create(device=self.device, name='Front Port 1:3')
+        frontport1_4 = FrontPort.objects.create(device=self.device, name='Front Port 1:4')
+        frontport2_1 = FrontPort.objects.create(device=self.device, name='Front Port 2:1')
+        frontport2_2 = FrontPort.objects.create(device=self.device, name='Front Port 2:2')
+        frontport2_3 = FrontPort.objects.create(device=self.device, name='Front Port 2:3')
+        frontport2_4 = FrontPort.objects.create(device=self.device, name='Front Port 2:4')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_3,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=3,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_4,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=4,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_1,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_3,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=3,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_4,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=4,
+            ),
+        ])
 
         # Create cables 1-2
         cable1 = Cable(
@@ -1858,22 +2112,44 @@ class LegacyCablePathTests(CablePathTestCase):
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=1)
-        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3', rear_port=rearport3, rear_port_position=1
-        )
-        frontport4 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4', rear_port=rearport4, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3')
+        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3 = FrontPort.objects.create(device=self.device, name='Front Port 3')
+        frontport4 = FrontPort.objects.create(device=self.device, name='Front Port 4')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+        ])
 
         cable2 = Cable(
             a_terminations=[rearport1],
@@ -1937,22 +2213,44 @@ class LegacyCablePathTests(CablePathTestCase):
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=1)
-        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3', rear_port=rearport3, rear_port_position=1
-        )
-        frontport4 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4', rear_port=rearport4, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3')
+        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3 = FrontPort.objects.create(device=self.device, name='Front Port 3')
+        frontport4 = FrontPort.objects.create(device=self.device, name='Front Port 4')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+        ])
 
         cable2 = Cable(
             a_terminations=[rearport1],
@@ -2033,30 +2331,62 @@ class LegacyCablePathTests(CablePathTestCase):
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3', positions=1)
-        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4', positions=1)
-        rearport5 = RearPort.objects.create(device=self.device, name='Rear Port 5', positions=1)
-        rearport6 = RearPort.objects.create(device=self.device, name='Rear Port 6', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3 = FrontPort.objects.create(
-            device=self.device, name='Front Port 3', rear_port=rearport3, rear_port_position=1
-        )
-        frontport4 = FrontPort.objects.create(
-            device=self.device, name='Front Port 4', rear_port=rearport4, rear_port_position=1
-        )
-        frontport5 = FrontPort.objects.create(
-            device=self.device, name='Front Port 5', rear_port=rearport5, rear_port_position=1
-        )
-        frontport6 = FrontPort.objects.create(
-            device=self.device, name='Front Port 6', rear_port=rearport6, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=self.device, name='Rear Port 3')
+        rearport4 = RearPort.objects.create(device=self.device, name='Rear Port 4')
+        rearport5 = RearPort.objects.create(device=self.device, name='Rear Port 5')
+        rearport6 = RearPort.objects.create(device=self.device, name='Rear Port 6')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3 = FrontPort.objects.create(device=self.device, name='Front Port 3')
+        frontport4 = FrontPort.objects.create(device=self.device, name='Front Port 4')
+        frontport5 = FrontPort.objects.create(device=self.device, name='Front Port 5')
+        frontport6 = FrontPort.objects.create(device=self.device, name='Front Port 6')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport5,
+                front_port_position=1,
+                rear_port=rearport5,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport6,
+                front_port_position=1,
+                rear_port=rearport6,
+                rear_port_position=1,
+            ),
+        ])
 
         cable2 = Cable(
             a_terminations=[rearport1],
@@ -2155,14 +2485,26 @@ class LegacyCablePathTests(CablePathTestCase):
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+        ])
 
         cable1 = Cable(
             a_terminations=[interface1],
@@ -2274,14 +2616,26 @@ class LegacyCablePathTests(CablePathTestCase):
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
         interface3 = Interface.objects.create(device=self.device, name='Interface 3')
         interface4 = Interface.objects.create(device=self.device, name='Interface 4')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+        ])
 
         # Create cables
         cable1 = Cable(
@@ -2320,14 +2674,26 @@ class LegacyCablePathTests(CablePathTestCase):
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+        ])
 
         # Create cable 2
         cable2 = Cable(
@@ -2373,10 +2739,17 @@ class LegacyCablePathTests(CablePathTestCase):
         """
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+        ])
 
         # Create cables 1 and 2
         cable1 = Cable(
@@ -2478,22 +2851,44 @@ class LegacyCablePathTests(CablePathTestCase):
         )
         interface1 = Interface.objects.create(device=self.device, name='Interface 1')
         interface2 = Interface.objects.create(device=self.device, name='Interface 2')
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        rearport3 = RearPort.objects.create(device=device, name='Rear Port 3', positions=1)
-        rearport4 = RearPort.objects.create(device=device, name='Rear Port 4', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
-        frontport3 = FrontPort.objects.create(
-            device=device, name='Front Port 3', rear_port=rearport3, rear_port_position=1
-        )
-        frontport4 = FrontPort.objects.create(
-            device=device, name='Front Port 4', rear_port=rearport4, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        rearport3 = RearPort.objects.create(device=device, name='Rear Port 3')
+        rearport4 = RearPort.objects.create(device=device, name='Rear Port 4')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        frontport3 = FrontPort.objects.create(device=self.device, name='Front Port 3')
+        frontport4 = FrontPort.objects.create(device=self.device, name='Front Port 4')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport3,
+                front_port_position=1,
+                rear_port=rearport3,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport4,
+                front_port_position=1,
+                rear_port=rearport4,
+                rear_port_position=1,
+            ),
+        ])
 
         cable2 = Cable(
             a_terminations=[rearport1],

netbox/dcim/tests/test_cablepaths2.py

@@ -1,5 +1,3 @@
-from unittest import skipIf
-
 from circuits.models import CircuitTermination
 from dcim.choices import CableProfileChoices
 from dcim.models import *
@@ -363,13 +361,17 @@ class CablePathTests(CablePathTestCase):
             Interface.objects.create(device=self.device, name='Interface 3'),
             Interface.objects.create(device=self.device, name='Interface 4'),
         ]
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device,
-            name='Front Port 1',
-            rear_port=rearport1,
-            rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+        ])
 
         # Create cables
         cable1 = Cable(
@@ -439,18 +441,40 @@ class CablePathTests(CablePathTestCase):
         ]
         rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=4)
         rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=4)
-        frontport1_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport1_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1:2', rear_port=rearport1, rear_port_position=2
-        )
-        frontport2_1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:1', rear_port=rearport2, rear_port_position=1
-        )
-        frontport2_2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2:2', rear_port=rearport2, rear_port_position=2
-        )
+        frontport1_1 = FrontPort.objects.create(device=self.device, name='Front Port 1:1')
+        frontport1_2 = FrontPort.objects.create(device=self.device, name='Front Port 1:2')
+        frontport2_1 = FrontPort.objects.create(device=self.device, name='Front Port 2:1')
+        frontport2_2 = FrontPort.objects.create(device=self.device, name='Front Port 2:2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport1_2,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=2,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_1,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2_2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=2,
+            ),
+        ])
 
         # Create cables
         cable1 = Cable(
@@ -654,25 +678,47 @@ class CablePathTests(CablePathTestCase):
             Interface.objects.create(device=self.device, name='Interface 2'),
         ]
         rear_ports = [
-            RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1),
-            RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1),
-            RearPort.objects.create(device=self.device, name='Rear Port 3', positions=1),
-            RearPort.objects.create(device=self.device, name='Rear Port 4', positions=1),
+            RearPort.objects.create(device=self.device, name='Rear Port 1'),
+            RearPort.objects.create(device=self.device, name='Rear Port 2'),
+            RearPort.objects.create(device=self.device, name='Rear Port 3'),
+            RearPort.objects.create(device=self.device, name='Rear Port 4'),
         ]
         front_ports = [
-            FrontPort.objects.create(
-                device=self.device, name='Front Port 1', rear_port=rear_ports[0], rear_port_position=1
+            FrontPort.objects.create(device=self.device, name='Front Port 1'),
+            FrontPort.objects.create(device=self.device, name='Front Port 2'),
+            FrontPort.objects.create(device=self.device, name='Front Port 3'),
+            FrontPort.objects.create(device=self.device, name='Front Port 4'),
+        ]
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=front_ports[0],
+                front_port_position=1,
+                rear_port=rear_ports[0],
+                rear_port_position=1,
             ),
-            FrontPort.objects.create(
-                device=self.device, name='Front Port 2', rear_port=rear_ports[1], rear_port_position=1
+            PortMapping(
+                device=self.device,
+                front_port=front_ports[1],
+                front_port_position=1,
+                rear_port=rear_ports[1],
+                rear_port_position=1,
             ),
-            FrontPort.objects.create(
-                device=self.device, name='Front Port 3', rear_port=rear_ports[2], rear_port_position=1
+            PortMapping(
+                device=self.device,
+                front_port=front_ports[2],
+                front_port_position=1,
+                rear_port=rear_ports[2],
+                rear_port_position=1,
             ),
-            FrontPort.objects.create(
-                device=self.device, name='Front Port 4', rear_port=rear_ports[3], rear_port_position=1
+            PortMapping(
+                device=self.device,
+                front_port=front_ports[3],
+                front_port_position=1,
+                rear_port=rear_ports[3],
+                rear_port_position=1,
             ),
-        ]
+        ])
 
         # Create cables
         cable1 = Cable(
@@ -723,8 +769,6 @@ class CablePathTests(CablePathTestCase):
         # Test SVG generation
         CableTraceSVG(interfaces[0]).render()
 
-    # TODO: Revisit this test under FR #20564
-    @skipIf(True, "Waiting for FR #20564")
     def test_223_single_path_via_multiple_pass_throughs_with_breakouts(self):
         """
         [IF1] --C1-- [FP1] [RP1] --C2-- [IF3]
@@ -736,14 +780,26 @@ class CablePathTests(CablePathTestCase):
             Interface.objects.create(device=self.device, name='Interface 3'),
             Interface.objects.create(device=self.device, name='Interface 4'),
         ]
-        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
-        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
-        frontport1 = FrontPort.objects.create(
-            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
-        )
-        frontport2 = FrontPort.objects.create(
-            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
-        )
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        PortMapping.objects.bulk_create([
+            PortMapping(
+                device=self.device,
+                front_port=frontport1,
+                front_port_position=1,
+                rear_port=rearport1,
+                rear_port_position=1,
+            ),
+            PortMapping(
+                device=self.device,
+                front_port=frontport2,
+                front_port_position=1,
+                rear_port=rearport2,
+                rear_port_position=1,
+            ),
+        ])
 
         # Create cables
         cable1 = Cable(
@@ -761,9 +817,6 @@ class CablePathTests(CablePathTestCase):
         cable2.clean()
         cable2.save()
 
-        for path in CablePath.objects.all():
-            print(f'{path}: {path.path_objects}')
-
         # Validate paths
         self.assertPathExists(
             (interfaces[0], cable1, [frontport1, frontport2], [rearport1, rearport2], cable2, interfaces[2]),
@@ -786,3 +839,205 @@ class CablePathTests(CablePathTestCase):
             is_active=True
         )
         self.assertEqual(CablePath.objects.count(), 4)
+
+    def test_304_add_port_mapping_between_connected_ports(self):
+        """
+        [IF1] --C1-- [FP1] [RP1] --C2-- [IF2]
+        """
+        interface1 = Interface.objects.create(device=self.device, name='Interface 1')
+        interface2 = Interface.objects.create(device=self.device, name='Interface 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        cable1 = Cable(
+            a_terminations=[interface1],
+            b_terminations=[frontport1]
+        )
+        cable1.save()
+        cable2 = Cable(
+            a_terminations=[interface2],
+            b_terminations=[rearport1]
+        )
+        cable2.save()
+
+        # Check for incomplete paths
+        self.assertPathExists(
+            (interface1, cable1, frontport1),
+            is_complete=False,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface2, cable2, rearport1),
+            is_complete=False,
+            is_active=True
+        )
+
+        # Create a PortMapping between frontport1 and rearport1
+        PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport1,
+            front_port_position=1,
+            rear_port=rearport1,
+            rear_port_position=1,
+        )
+
+        # Check that paths are now complete
+        self.assertPathExists(
+            (interface1, cable1, frontport1, rearport1, cable2, interface2),
+            is_complete=True,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface2, cable2, rearport1, frontport1, cable1, interface1),
+            is_complete=True,
+            is_active=True
+        )
+
+    def test_305_delete_port_mapping_between_connected_ports(self):
+        """
+        [IF1] --C1-- [FP1] [RP1] --C2-- [IF2]
+        """
+        interface1 = Interface.objects.create(device=self.device, name='Interface 1')
+        interface2 = Interface.objects.create(device=self.device, name='Interface 2')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        cable1 = Cable(
+            a_terminations=[interface1],
+            b_terminations=[frontport1]
+        )
+        cable1.save()
+        cable2 = Cable(
+            a_terminations=[interface2],
+            b_terminations=[rearport1]
+        )
+        cable2.save()
+        portmapping1 = PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport1,
+            front_port_position=1,
+            rear_port=rearport1,
+            rear_port_position=1,
+        )
+
+        # Check for complete paths
+        self.assertPathExists(
+            (interface1, cable1, frontport1, rearport1, cable2, interface2),
+            is_complete=True,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface2, cable2, rearport1, frontport1, cable1, interface1),
+            is_complete=True,
+            is_active=True
+        )
+
+        # Delete the PortMapping between frontport1 and rearport1
+        portmapping1.delete()
+
+        # Check that paths are no longer complete
+        self.assertPathExists(
+            (interface1, cable1, frontport1),
+            is_complete=False,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface2, cable2, rearport1),
+            is_complete=False,
+            is_active=True
+        )
+
+    def test_306_change_port_mapping_between_connected_ports(self):
+        """
+        [IF1] --C1-- [FP1] [RP1] --C3-- [IF3]
+        [IF2] --C2-- [FP2] [RP3] --C4-- [IF4]
+        """
+        interface1 = Interface.objects.create(device=self.device, name='Interface 1')
+        interface2 = Interface.objects.create(device=self.device, name='Interface 2')
+        interface3 = Interface.objects.create(device=self.device, name='Interface 3')
+        interface4 = Interface.objects.create(device=self.device, name='Interface 4')
+        frontport1 = FrontPort.objects.create(device=self.device, name='Front Port 1')
+        frontport2 = FrontPort.objects.create(device=self.device, name='Front Port 2')
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1')
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2')
+        cable1 = Cable(
+            a_terminations=[interface1],
+            b_terminations=[frontport1]
+        )
+        cable1.save()
+        cable2 = Cable(
+            a_terminations=[interface2],
+            b_terminations=[frontport2]
+        )
+        cable2.save()
+        cable3 = Cable(
+            a_terminations=[interface3],
+            b_terminations=[rearport1]
+        )
+        cable3.save()
+        cable4 = Cable(
+            a_terminations=[interface4],
+            b_terminations=[rearport2]
+        )
+        cable4.save()
+        portmapping1 = PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport1,
+            front_port_position=1,
+            rear_port=rearport1,
+            rear_port_position=1,
+        )
+
+        # Verify expected initial paths
+        self.assertPathExists(
+            (interface1, cable1, frontport1, rearport1, cable3, interface3),
+            is_complete=True,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface3, cable3, rearport1, frontport1, cable1, interface1),
+            is_complete=True,
+            is_active=True
+        )
+
+        # Delete and replace the PortMapping to connect interface1 to interface4
+        portmapping1.delete()
+        portmapping2 = PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport1,
+            front_port_position=1,
+            rear_port=rearport2,
+            rear_port_position=1,
+        )
+
+        # Verify expected new paths
+        self.assertPathExists(
+            (interface1, cable1, frontport1, rearport2, cable4, interface4),
+            is_complete=True,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface4, cable4, rearport2, frontport1, cable1, interface1),
+            is_complete=True,
+            is_active=True
+        )
+
+        # Delete and replace the PortMapping to connect interface2 to interface4
+        portmapping2.delete()
+        PortMapping.objects.create(
+            device=self.device,
+            front_port=frontport2,
+            front_port_position=1,
+            rear_port=rearport2,
+            rear_port_position=1,
+        )
+
+        # Verify expected new paths
+        self.assertPathExists(
+            (interface2, cable2, frontport2, rearport2, cable4, interface4),
+            is_complete=True,
+            is_active=True
+        )
+        self.assertPathExists(
+            (interface4, cable4, rearport2, frontport2, cable2, interface2),
+            is_complete=True,
+            is_active=True
+        )

netbox/dcim/tests/test_filtersets.py

@@ -1362,22 +1362,15 @@ class DeviceTypeTestCase(TestCase, ChangeLoggedFilterSetTests):
             RearPortTemplate(device_type=device_types[1], name='Rear Port 2', type=PortTypeChoices.TYPE_8P8C),
         )
         RearPortTemplate.objects.bulk_create(rear_ports)
-        FrontPortTemplate.objects.bulk_create(
-            (
-                FrontPortTemplate(
-                    device_type=device_types[0],
-                    name='Front Port 1',
-                    type=PortTypeChoices.TYPE_8P8C,
-                    rear_port=rear_ports[0],
-                ),
-                FrontPortTemplate(
-                    device_type=device_types[1],
-                    name='Front Port 2',
-                    type=PortTypeChoices.TYPE_8P8C,
-                    rear_port=rear_ports[1],
-                ),
-            )
-        )
+        front_ports = (
+            FrontPortTemplate(device_type=device_types[0], name='Front Port 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(device_type=device_types[1], name='Front Port 2', type=PortTypeChoices.TYPE_8P8C),
+        )
+        FrontPortTemplate.objects.bulk_create(front_ports)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(device_type=device_types[0], front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortTemplateMapping(device_type=device_types[1], front_port=front_ports[1], rear_port=rear_ports[1]),
+        ])
         ModuleBayTemplate.objects.bulk_create((
             ModuleBayTemplate(device_type=device_types[0], name='Module Bay 1'),
             ModuleBayTemplate(device_type=device_types[1], name='Module Bay 2'),
@@ -1633,22 +1626,15 @@ class ModuleTypeTestCase(TestCase, ChangeLoggedFilterSetTests):
             RearPortTemplate(module_type=module_types[1], name='Rear Port 2', type=PortTypeChoices.TYPE_8P8C),
         )
         RearPortTemplate.objects.bulk_create(rear_ports)
-        FrontPortTemplate.objects.bulk_create(
-            (
-                FrontPortTemplate(
-                    module_type=module_types[0],
-                    name='Front Port 1',
-                    type=PortTypeChoices.TYPE_8P8C,
-                    rear_port=rear_ports[0],
-                ),
-                FrontPortTemplate(
-                    module_type=module_types[1],
-                    name='Front Port 2',
-                    type=PortTypeChoices.TYPE_8P8C,
-                    rear_port=rear_ports[1],
-                ),
-            )
+        front_ports = (
+            FrontPortTemplate(module_type=module_types[0], name='Front Port 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPortTemplate(module_type=module_types[1], name='Front Port 2', type=PortTypeChoices.TYPE_8P8C),
         )
+        FrontPortTemplate.objects.bulk_create(front_ports)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(module_type=module_types[0], front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortTemplateMapping(module_type=module_types[1], front_port=front_ports[1], rear_port=rear_ports[1]),
+        ])
 
     def test_q(self):
         params = {'q': 'foobar1'}
@@ -2064,32 +2050,38 @@ class FrontPortTemplateTestCase(TestCase, DeviceComponentTemplateFilterSetTests,
         )
         RearPortTemplate.objects.bulk_create(rear_ports)
 
-        FrontPortTemplate.objects.bulk_create((
+        front_ports = (
             FrontPortTemplate(
                 device_type=device_types[0],
                 name='Front Port 1',
-                rear_port=rear_ports[0],
                 type=PortTypeChoices.TYPE_8P8C,
+                positions=1,
                 color=ColorChoices.COLOR_RED,
                 description='foobar1'
             ),
             FrontPortTemplate(
                 device_type=device_types[1],
                 name='Front Port 2',
-                rear_port=rear_ports[1],
                 type=PortTypeChoices.TYPE_110_PUNCH,
+                positions=2,
                 color=ColorChoices.COLOR_GREEN,
                 description='foobar2'
             ),
             FrontPortTemplate(
                 device_type=device_types[2],
                 name='Front Port 3',
-                rear_port=rear_ports[2],
                 type=PortTypeChoices.TYPE_BNC,
+                positions=3,
                 color=ColorChoices.COLOR_BLUE,
                 description='foobar3'
             ),
-        ))
+        )
+        FrontPortTemplate.objects.bulk_create(front_ports)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(device_type=device_types[0], front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortTemplateMapping(device_type=device_types[1], front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortTemplateMapping(device_type=device_types[2], front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
     def test_name(self):
         params = {'name': ['Front Port 1', 'Front Port 2']}
@@ -2103,6 +2095,10 @@ class FrontPortTemplateTestCase(TestCase, DeviceComponentTemplateFilterSetTests,
         params = {'color': [ColorChoices.COLOR_RED, ColorChoices.COLOR_GREEN]}
         self.assertEqual(self.filterset(params, self.queryset).qs.count(), 2)
 
+    def test_positions(self):
+        params = {'positions': [1, 2]}
+        self.assertEqual(self.filterset(params, self.queryset).qs.count(), 2)
+
 
 class RearPortTemplateTestCase(TestCase, DeviceComponentTemplateFilterSetTests, ChangeLoggedFilterSetTests):
     queryset = RearPortTemplate.objects.all()
@@ -2759,10 +2755,15 @@ class DeviceTestCase(TestCase, ChangeLoggedFilterSetTests):
             RearPort(device=devices[1], name='Rear Port 2', type=PortTypeChoices.TYPE_8P8C),
         )
         RearPort.objects.bulk_create(rear_ports)
-        FrontPort.objects.bulk_create((
-            FrontPort(device=devices[0], name='Front Port 1', type=PortTypeChoices.TYPE_8P8C, rear_port=rear_ports[0]),
-            FrontPort(device=devices[1], name='Front Port 2', type=PortTypeChoices.TYPE_8P8C, rear_port=rear_ports[1]),
-        ))
+        front_ports = (
+            FrontPort(device=devices[0], name='Front Port 1', type=PortTypeChoices.TYPE_8P8C),
+            FrontPort(device=devices[1], name='Front Port 2', type=PortTypeChoices.TYPE_8P8C),
+        )
+        FrontPort.objects.bulk_create(front_ports)
+        PortMapping.objects.bulk_create([
+            PortMapping(device=devices[0], front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortMapping(device=devices[1], front_port=front_ports[1], rear_port=rear_ports[1]),
+        ])
         ModuleBay.objects.create(device=devices[0], name='Module Bay 1')
         ModuleBay.objects.create(device=devices[1], name='Module Bay 2')
         DeviceBay.objects.bulk_create((
@@ -5158,8 +5159,6 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
                 label='A',
                 type=PortTypeChoices.TYPE_8P8C,
                 color=ColorChoices.COLOR_RED,
-                rear_port=rear_ports[0],
-                rear_port_position=1,
                 description='First',
                 _site=devices[0].site,
                 _location=devices[0].location,
@@ -5172,8 +5171,6 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
                 label='B',
                 type=PortTypeChoices.TYPE_110_PUNCH,
                 color=ColorChoices.COLOR_GREEN,
-                rear_port=rear_ports[1],
-                rear_port_position=2,
                 description='Second',
                 _site=devices[1].site,
                 _location=devices[1].location,
@@ -5186,8 +5183,6 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
                 label='C',
                 type=PortTypeChoices.TYPE_BNC,
                 color=ColorChoices.COLOR_BLUE,
-                rear_port=rear_ports[2],
-                rear_port_position=3,
                 description='Third',
                 _site=devices[2].site,
                 _location=devices[2].location,
@@ -5198,8 +5193,7 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
                 name='Front Port 4',
                 label='D',
                 type=PortTypeChoices.TYPE_FC,
-                rear_port=rear_ports[3],
-                rear_port_position=1,
+                positions=2,
                 _site=devices[3].site,
                 _location=devices[3].location,
                 _rack=devices[3].rack,
@@ -5209,8 +5203,7 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
                 name='Front Port 5',
                 label='E',
                 type=PortTypeChoices.TYPE_FC,
-                rear_port=rear_ports[4],
-                rear_port_position=1,
+                positions=3,
                 _site=devices[3].site,
                 _location=devices[3].location,
                 _rack=devices[3].rack,
@@ -5220,14 +5213,21 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
                 name='Front Port 6',
                 label='F',
                 type=PortTypeChoices.TYPE_FC,
-                rear_port=rear_ports[5],
-                rear_port_position=1,
+                positions=4,
                 _site=devices[3].site,
                 _location=devices[3].location,
                 _rack=devices[3].rack,
             ),
         )
         FrontPort.objects.bulk_create(front_ports)
+        PortMapping.objects.bulk_create([
+            PortMapping(device=devices[0], front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortMapping(device=devices[1], front_port=front_ports[1], rear_port=rear_ports[1], rear_port_position=2),
+            PortMapping(device=devices[2], front_port=front_ports[2], rear_port=rear_ports[2], rear_port_position=3),
+            PortMapping(device=devices[3], front_port=front_ports[3], rear_port=rear_ports[3]),
+            PortMapping(device=devices[3], front_port=front_ports[4], rear_port=rear_ports[4]),
+            PortMapping(device=devices[3], front_port=front_ports[5], rear_port=rear_ports[5]),
+        ])
 
         # Cables
         Cable(a_terminations=[front_ports[0]], b_terminations=[front_ports[3]]).save()
@@ -5250,6 +5250,10 @@ class FrontPortTestCase(TestCase, DeviceComponentFilterSetTests, ChangeLoggedFil
         params = {'color': [ColorChoices.COLOR_RED, ColorChoices.COLOR_GREEN]}
         self.assertEqual(self.filterset(params, self.queryset).qs.count(), 2)
 
+    def test_positions(self):
+        params = {'positions': [2, 3]}
+        self.assertEqual(self.filterset(params, self.queryset).qs.count(), 2)
+
     def test_description(self):
         params = {'description': ['First', 'Second']}
         self.assertEqual(self.filterset(params, self.queryset).qs.count(), 2)
@@ -6518,13 +6522,9 @@ class CableTestCase(TestCase, ChangeLoggedFilterSetTests):
         console_server_port = ConsoleServerPort.objects.create(device=devices[0], name='Console Server Port 1')
         power_port = PowerPort.objects.create(device=devices[0], name='Power Port 1')
         power_outlet = PowerOutlet.objects.create(device=devices[0], name='Power Outlet 1')
-        rear_port = RearPort.objects.create(device=devices[0], name='Rear Port 1', positions=1)
-        front_port = FrontPort.objects.create(
-            device=devices[0],
-            name='Front Port 1',
-            rear_port=rear_port,
-            rear_port_position=1
-        )
+        rear_port = RearPort.objects.create(device=devices[0], name='Rear Port 1')
+        front_port = FrontPort.objects.create(device=devices[0], name='Front Port 1')
+        PortMapping.objects.create(device=devices[0], front_port=front_port, rear_port=rear_port)
 
         power_panel = PowerPanel.objects.create(name='Power Panel 1', site=sites[0])
         power_feed = PowerFeed.objects.create(name='Power Feed 1', power_panel=power_panel)

netbox/dcim/tests/test_forms.py

@@ -193,7 +193,8 @@ class FrontPortTestCase(TestCase):
             'name': 'FrontPort[1-4]',
             'label': 'Port[1-4]',
             'type': PortTypeChoices.TYPE_8P8C,
-            'rear_port': [f'{rear_port.pk}:1' for rear_port in self.rear_ports],
+            'positions': 1,
+            'rear_ports': [f'{rear_port.pk}:1' for rear_port in self.rear_ports],
         }
         form = FrontPortCreateForm(front_port_data)
 
@@ -208,7 +209,8 @@ class FrontPortTestCase(TestCase):
             'name': 'FrontPort[1-4]',
             'label': 'Port[1-2]',
             'type': PortTypeChoices.TYPE_8P8C,
-            'rear_port': [f'{rear_port.pk}:1' for rear_port in self.rear_ports],
+            'positions': 1,
+            'rear_ports': [f'{rear_port.pk}:1' for rear_port in self.rear_ports],
         }
         form = FrontPortCreateForm(bad_front_port_data)
 

netbox/dcim/tests/test_models.py

@@ -444,13 +444,19 @@ class DeviceTestCase(TestCase):
         )
         rearport.save()
 
-        FrontPortTemplate(
+        frontport = FrontPortTemplate(
             device_type=device_type,
             name='Front Port 1',
             type=PortTypeChoices.TYPE_8P8C,
+        )
+        frontport.save()
+
+        PortTemplateMapping.objects.create(
+            device_type=device_type,
+            front_port=frontport,
             rear_port=rearport,
-            rear_port_position=2
-        ).save()
+            rear_port_position=2,
+        )
 
         ModuleBayTemplate(
             device_type=device_type,
@@ -528,11 +534,12 @@ class DeviceTestCase(TestCase):
             device=device,
             name='Front Port 1',
             type=PortTypeChoices.TYPE_8P8C,
-            rear_port=rearport,
-            rear_port_position=2
+            positions=1
         )
         self.assertEqual(frontport.cf['cf1'], 'foo')
 
+        self.assertTrue(PortMapping.objects.filter(front_port=frontport, rear_port=rearport).exists())
+
         modulebay = ModuleBay.objects.get(
             device=device,
             name='Module Bay 1'
@@ -881,12 +888,18 @@ class CableTestCase(TestCase):
         )
         RearPort.objects.bulk_create(rear_ports)
         front_ports = (
-            FrontPort(device=patch_panel, name='FP1', type='8p8c', rear_port=rear_ports[0], rear_port_position=1),
-            FrontPort(device=patch_panel, name='FP2', type='8p8c', rear_port=rear_ports[1], rear_port_position=1),
-            FrontPort(device=patch_panel, name='FP3', type='8p8c', rear_port=rear_ports[2], rear_port_position=1),
-            FrontPort(device=patch_panel, name='FP4', type='8p8c', rear_port=rear_ports[3], rear_port_position=1),
+            FrontPort(device=patch_panel, name='FP1', type='8p8c'),
+            FrontPort(device=patch_panel, name='FP2', type='8p8c'),
+            FrontPort(device=patch_panel, name='FP3', type='8p8c'),
+            FrontPort(device=patch_panel, name='FP4', type='8p8c'),
         )
         FrontPort.objects.bulk_create(front_ports)
+        PortMapping.objects.bulk_create([
+            PortMapping(device=patch_panel, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortMapping(device=patch_panel, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortMapping(device=patch_panel, front_port=front_ports[2], rear_port=rear_ports[2]),
+            PortMapping(device=patch_panel, front_port=front_ports[3], rear_port=rear_ports[3]),
+        ])
 
         provider = Provider.objects.create(name='Provider 1', slug='provider-1')
         provider_network = ProviderNetwork.objects.create(name='Provider Network 1', provider=provider)

netbox/dcim/tests/test_views.py

@@ -741,17 +741,16 @@ class DeviceTypeTestCase(
         )
         RearPortTemplate.objects.bulk_create(rear_ports)
         front_ports = (
-            FrontPortTemplate(
-                device_type=devicetype, name='Front Port 1', rear_port=rear_ports[0], rear_port_position=1
-            ),
-            FrontPortTemplate(
-                device_type=devicetype, name='Front Port 2', rear_port=rear_ports[1], rear_port_position=1
-            ),
-            FrontPortTemplate(
-                device_type=devicetype, name='Front Port 3', rear_port=rear_ports[2], rear_port_position=1
-            ),
+            FrontPortTemplate(device_type=devicetype, name='Front Port 1'),
+            FrontPortTemplate(device_type=devicetype, name='Front Port 2'),
+            FrontPortTemplate(device_type=devicetype, name='Front Port 3'),
         )
         FrontPortTemplate.objects.bulk_create(front_ports)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(device_type=devicetype, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortTemplateMapping(device_type=devicetype, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortTemplateMapping(device_type=devicetype, front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
         url = reverse('dcim:devicetype_frontports', kwargs={'pk': devicetype.pk})
         self.assertHttpStatus(self.client.get(url), 200)
@@ -866,12 +865,16 @@ rear-ports:
 front-ports:
   - name: Front Port 1
     type: 8p8c
-    rear_port: Rear Port 1
   - name: Front Port 2
     type: 8p8c
-    rear_port: Rear Port 2
   - name: Front Port 3
     type: 8p8c
+port-mappings:
+  - front_port: Front Port 1
+    rear_port: Rear Port 1
+  - front_port: Front Port 2
+    rear_port: Rear Port 2
+  - front_port: Front Port 3
     rear_port: Rear Port 3
 module-bays:
   - name: Module Bay 1
@@ -971,8 +974,12 @@ inventory-items:
         self.assertEqual(device_type.frontporttemplates.count(), 3)
         fp1 = FrontPortTemplate.objects.first()
         self.assertEqual(fp1.name, 'Front Port 1')
-        self.assertEqual(fp1.rear_port, rp1)
-        self.assertEqual(fp1.rear_port_position, 1)
+
+        self.assertEqual(device_type.port_mappings.count(), 3)
+        mapping1 = PortTemplateMapping.objects.first()
+        self.assertEqual(mapping1.device_type, device_type)
+        self.assertEqual(mapping1.front_port, fp1)
+        self.assertEqual(mapping1.rear_port, rp1)
 
         self.assertEqual(device_type.modulebaytemplates.count(), 3)
         mb1 = ModuleBayTemplate.objects.first()
@@ -1316,17 +1323,16 @@ class ModuleTypeTestCase(ViewTestCases.PrimaryObjectViewTestCase):
         )
         RearPortTemplate.objects.bulk_create(rear_ports)
         front_ports = (
-            FrontPortTemplate(
-                module_type=moduletype, name='Front Port 1', rear_port=rear_ports[0], rear_port_position=1
-            ),
-            FrontPortTemplate(
-                module_type=moduletype, name='Front Port 2', rear_port=rear_ports[1], rear_port_position=1
-            ),
-            FrontPortTemplate(
-                module_type=moduletype, name='Front Port 3', rear_port=rear_ports[2], rear_port_position=1
-            ),
+            FrontPortTemplate(module_type=moduletype, name='Front Port 1'),
+            FrontPortTemplate(module_type=moduletype, name='Front Port 2'),
+            FrontPortTemplate(module_type=moduletype, name='Front Port 3'),
         )
         FrontPortTemplate.objects.bulk_create(front_ports)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(module_type=moduletype, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortTemplateMapping(module_type=moduletype, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortTemplateMapping(module_type=moduletype, front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
         url = reverse('dcim:moduletype_frontports', kwargs={'pk': moduletype.pk})
         self.assertHttpStatus(self.client.get(url), 200)
@@ -1394,12 +1400,16 @@ rear-ports:
 front-ports:
   - name: Front Port 1
     type: 8p8c
-    rear_port: Rear Port 1
   - name: Front Port 2
     type: 8p8c
-    rear_port: Rear Port 2
   - name: Front Port 3
     type: 8p8c
+port-mappings:
+  - front_port: Front Port 1
+    rear_port: Rear Port 1
+  - front_port: Front Port 2
+    rear_port: Rear Port 2
+  - front_port: Front Port 3
     rear_port: Rear Port 3
 module-bays:
   - name: Module Bay 1
@@ -1477,8 +1487,12 @@ module-bays:
         self.assertEqual(module_type.frontporttemplates.count(), 3)
         fp1 = FrontPortTemplate.objects.first()
         self.assertEqual(fp1.name, 'Front Port 1')
-        self.assertEqual(fp1.rear_port, rp1)
-        self.assertEqual(fp1.rear_port_position, 1)
+
+        self.assertEqual(module_type.port_mappings.count(), 3)
+        mapping1 = PortTemplateMapping.objects.first()
+        self.assertEqual(mapping1.module_type, module_type)
+        self.assertEqual(mapping1.front_port, fp1)
+        self.assertEqual(mapping1.rear_port, rp1)
 
         self.assertEqual(module_type.modulebaytemplates.count(), 3)
         mb1 = ModuleBayTemplate.objects.first()
@@ -1770,7 +1784,7 @@ class FrontPortTemplateTestCase(ViewTestCases.DeviceComponentTemplateViewTestCas
         manufacturer = Manufacturer.objects.create(name='Manufacturer 1', slug='manufacturer-1')
         devicetype = DeviceType.objects.create(manufacturer=manufacturer, model='Device Type 1', slug='device-type-1')
 
-        rearports = (
+        rear_ports = (
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 1'),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 2'),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 3'),
@@ -1778,35 +1792,33 @@ class FrontPortTemplateTestCase(ViewTestCases.DeviceComponentTemplateViewTestCas
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 5'),
             RearPortTemplate(device_type=devicetype, name='Rear Port Template 6'),
         )
-        RearPortTemplate.objects.bulk_create(rearports)
-
-        FrontPortTemplate.objects.bulk_create(
-            (
-                FrontPortTemplate(
-                    device_type=devicetype, name='Front Port Template 1', rear_port=rearports[0], rear_port_position=1
-                ),
-                FrontPortTemplate(
-                    device_type=devicetype, name='Front Port Template 2', rear_port=rearports[1], rear_port_position=1
-                ),
-                FrontPortTemplate(
-                    device_type=devicetype, name='Front Port Template 3', rear_port=rearports[2], rear_port_position=1
-                ),
-            )
+        RearPortTemplate.objects.bulk_create(rear_ports)
+        front_ports = (
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 1'),
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 2'),
+            FrontPortTemplate(device_type=devicetype, name='Front Port Template 3'),
         )
+        FrontPortTemplate.objects.bulk_create(front_ports)
+        PortTemplateMapping.objects.bulk_create([
+            PortTemplateMapping(device_type=devicetype, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortTemplateMapping(device_type=devicetype, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortTemplateMapping(device_type=devicetype, front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
         cls.form_data = {
             'device_type': devicetype.pk,
             'name': 'Front Port X',
             'type': PortTypeChoices.TYPE_8P8C,
-            'rear_port': rearports[3].pk,
-            'rear_port_position': 1,
+            'positions': 1,
+            'rear_ports': [f'{rear_ports[3].pk}:1'],
         }
 
         cls.bulk_create_data = {
             'device_type': devicetype.pk,
             'name': 'Front Port [4-6]',
             'type': PortTypeChoices.TYPE_8P8C,
-            'rear_port': [f'{rp.pk}:1' for rp in rearports[3:6]],
+            'positions': 1,
+            'rear_ports': [f'{rp.pk}:1' for rp in rear_ports[3:6]],
         }
 
         cls.bulk_edit_data = {
@@ -2276,11 +2288,16 @@ class DeviceTestCase(ViewTestCases.PrimaryObjectViewTestCase):
         )
         RearPort.objects.bulk_create(rear_ports)
         front_ports = (
-            FrontPort(device=device, name='Front Port 1', rear_port=rear_ports[0], rear_port_position=1),
-            FrontPort(device=device, name='Front Port 2', rear_port=rear_ports[1], rear_port_position=1),
-            FrontPort(device=device, name='Front Port 3', rear_port=rear_ports[2], rear_port_position=1),
+            FrontPort(device=device, name='Front Port Template 1'),
+            FrontPort(device=device, name='Front Port Template 2'),
+            FrontPort(device=device, name='Front Port Template 3'),
         )
         FrontPort.objects.bulk_create(front_ports)
+        PortMapping.objects.bulk_create([
+            PortMapping(device=device, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortMapping(device=device, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortMapping(device=device, front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
         url = reverse('dcim:device_frontports', kwargs={'pk': device.pk})
         self.assertHttpStatus(self.client.get(url), 200)
@@ -3065,7 +3082,7 @@ class FrontPortTestCase(ViewTestCases.DeviceComponentViewTestCase):
     def setUpTestData(cls):
         device = create_test_device('Device 1')
 
-        rearports = (
+        rear_ports = (
             RearPort(device=device, name='Rear Port 1'),
             RearPort(device=device, name='Rear Port 2'),
             RearPort(device=device, name='Rear Port 3'),
@@ -3073,14 +3090,19 @@ class FrontPortTestCase(ViewTestCases.DeviceComponentViewTestCase):
             RearPort(device=device, name='Rear Port 5'),
             RearPort(device=device, name='Rear Port 6'),
         )
-        RearPort.objects.bulk_create(rearports)
+        RearPort.objects.bulk_create(rear_ports)
 
         front_ports = (
-            FrontPort(device=device, name='Front Port 1', rear_port=rearports[0]),
-            FrontPort(device=device, name='Front Port 2', rear_port=rearports[1]),
-            FrontPort(device=device, name='Front Port 3', rear_port=rearports[2]),
+            FrontPort(device=device, name='Front Port 1'),
+            FrontPort(device=device, name='Front Port 2'),
+            FrontPort(device=device, name='Front Port 3'),
         )
         FrontPort.objects.bulk_create(front_ports)
+        PortMapping.objects.bulk_create([
+            PortMapping(device=device, front_port=front_ports[0], rear_port=rear_ports[0]),
+            PortMapping(device=device, front_port=front_ports[1], rear_port=rear_ports[1]),
+            PortMapping(device=device, front_port=front_ports[2], rear_port=rear_ports[2]),
+        ])
 
         tags = create_tags('Alpha', 'Bravo', 'Charlie')
 
@@ -3088,8 +3110,8 @@ class FrontPortTestCase(ViewTestCases.DeviceComponentViewTestCase):
             'device': device.pk,
             'name': 'Front Port X',
             'type': PortTypeChoices.TYPE_8P8C,
-            'rear_port': rearports[3].pk,
-            'rear_port_position': 1,
+            'positions': 1,
+            'rear_ports': [f'{rear_ports[3].pk}:1'],
             'description': 'New description',
             'tags': [t.pk for t in tags],
         }
@@ -3098,7 +3120,8 @@ class FrontPortTestCase(ViewTestCases.DeviceComponentViewTestCase):
             'device': device.pk,
             'name': 'Front Port [4-6]',
             'type': PortTypeChoices.TYPE_8P8C,
-            'rear_port': [f'{rp.pk}:1' for rp in rearports[3:6]],
+            'positions': 1,
+            'rear_ports': [f'{rp.pk}:1' for rp in rear_ports[3:6]],
             'description': 'New description',
             'tags': [t.pk for t in tags],
         }
@@ -3109,10 +3132,10 @@ class FrontPortTestCase(ViewTestCases.DeviceComponentViewTestCase):
         }
 
         cls.csv_data = (
-            "device,name,type,rear_port,rear_port_position",
-            "Device 1,Front Port 4,8p8c,Rear Port 4,1",
-            "Device 1,Front Port 5,8p8c,Rear Port 5,1",
-            "Device 1,Front Port 6,8p8c,Rear Port 6,1",
+            "device,name,type,positions",
+            "Device 1,Front Port 4,8p8c,1",
+            "Device 1,Front Port 5,8p8c,1",
+            "Device 1,Front Port 6,8p8c,1",
         )
 
         cls.csv_update_data = (

netbox/dcim/utils.py

@@ -83,3 +83,36 @@ def update_interface_bridges(device, interface_templates, module=None):
             )
             interface.full_clean()
             interface.save()
+
+
+def create_port_mappings(device, device_type, module=None):
+    """
+    Replicate all front/rear port mappings from a DeviceType to the given device.
+    """
+    from dcim.models import FrontPort, PortMapping, RearPort
+
+    templates = device_type.port_mappings.prefetch_related('front_port', 'rear_port')
+
+    # Cache front & rear ports for efficient lookups by name
+    front_ports = {
+        fp.name: fp for fp in FrontPort.objects.filter(device=device)
+    }
+    rear_ports = {
+        rp.name: rp for rp in RearPort.objects.filter(device=device)
+    }
+
+    # Replicate PortMappings
+    mappings = []
+    for template in templates:
+        front_port = front_ports.get(template.front_port.resolve_name(module=module))
+        rear_port = rear_ports.get(template.rear_port.resolve_name(module=module))
+        mappings.append(
+            PortMapping(
+                device_id=front_port.device_id,
+                front_port=front_port,
+                front_port_position=template.front_port_position,
+                rear_port=rear_port,
+                rear_port_position=template.rear_port_position,
+            )
+        )
+    PortMapping.objects.bulk_create(mappings)

netbox/dcim/views.py

@@ -42,6 +42,7 @@ from wireless.models import WirelessLAN
 from . import filtersets, forms, tables
 from .choices import DeviceFaceChoices, InterfaceModeChoices
 from .models import *
+from .models.device_components import PortMapping
 from .object_actions import BulkAddComponents, BulkDisconnect
 
 CABLE_TERMINATION_TYPES = {
@@ -1515,6 +1516,7 @@ class DeviceTypeImportView(generic.BulkImportView):
         'interfaces': forms.InterfaceTemplateImportForm,
         'rear-ports': forms.RearPortTemplateImportForm,
         'front-ports': forms.FrontPortTemplateImportForm,
+        'port-mappings': forms.PortTemplateMappingImportForm,
         'module-bays': forms.ModuleBayTemplateImportForm,
         'device-bays': forms.DeviceBayTemplateImportForm,
         'inventory-items': forms.InventoryItemTemplateImportForm,
@@ -1819,6 +1821,7 @@ class ModuleTypeImportView(generic.BulkImportView):
         'interfaces': forms.InterfaceTemplateImportForm,
         'rear-ports': forms.RearPortTemplateImportForm,
         'front-ports': forms.FrontPortTemplateImportForm,
+        'port-mappings': forms.PortTemplateMappingImportForm,
         'module-bays': forms.ModuleBayTemplateImportForm,
     }
 
@@ -3242,6 +3245,11 @@ class FrontPortListView(generic.ObjectListView):
 class FrontPortView(generic.ObjectView):
     queryset = FrontPort.objects.all()
 
+    def get_extra_context(self, request, instance):
+        return {
+            'rear_port_mappings': PortMapping.objects.filter(front_port=instance).prefetch_related('rear_port'),
+        }
+
 
 @register_model_view(FrontPort, 'add', detail=False)
 class FrontPortCreateView(generic.ComponentCreateView):
@@ -3313,6 +3321,11 @@ class RearPortListView(generic.ObjectListView):
 class RearPortView(generic.ObjectView):
     queryset = RearPort.objects.all()
 
+    def get_extra_context(self, request, instance):
+        return {
+            'front_port_mappings': PortMapping.objects.filter(rear_port=instance).prefetch_related('front_port'),
+        }
+
 
 @register_model_view(RearPort, 'add', detail=False)
 class RearPortCreateView(generic.ComponentCreateView):

netbox/netbox/views/generic/object_views.py

@@ -1,6 +1,5 @@
 import logging
 from collections import defaultdict
-from copy import deepcopy
 
 from django.contrib import messages
 from django.db import router, transaction
@@ -564,7 +563,7 @@ class ComponentCreateView(GetReturnURLMixin, BaseObjectView):
         if form.is_valid():
             changelog_message = form.cleaned_data.pop('changelog_message', '')
             new_components = []
-            data = deepcopy(request.POST)
+            data = request.POST.copy()
             pattern_count = len(form.cleaned_data[self.form.replication_fields[0]])
 
             for i in range(pattern_count):
@@ -573,7 +572,8 @@ class ComponentCreateView(GetReturnURLMixin, BaseObjectView):
                         data[field_name] = form.cleaned_data[field_name][i]
 
                 if hasattr(form, 'get_iterative_data'):
-                    data.update(form.get_iterative_data(i))
+                    for k, v in form.get_iterative_data(i).items():
+                        data.setlist(k, v)
 
                 component_form = self.model_form(data)
 

netbox/templates/dcim/frontport.html

@@ -47,12 +47,8 @@
                       </td>
                     </tr>
                     <tr>
-                        <th scope="row">{% trans "Rear Port" %}</th>
-                        <td>{{ object.rear_port|linkify }}</td>
-                    </tr>
-                    <tr>
-                        <th scope="row">{% trans "Rear Port Position" %}</th>
-                        <td>{{ object.rear_port_position }}</td>
+                        <th scope="row">{% trans "Positions" %}</th>
+                        <td>{{ object.positions }}</td>
                     </tr>
                     <tr>
                         <th scope="row">{% trans "Description" %}</th>
@@ -62,6 +58,7 @@
             </div>
             {% include 'inc/panels/custom_fields.html' %}
             {% include 'inc/panels/tags.html' %}
+            {% include 'dcim/inc/panels/inventory_items.html' %}
             {% plugin_left_page object %}
         </div>
         <div class="col col-12 col-md-6">
@@ -126,7 +123,29 @@
                     </div>
                 {% endif %}
             </div>
-            {% include 'dcim/inc/panels/inventory_items.html' %}
+            <div class="card">
+              <h2 class="card-header">{% trans "Port Mappings" %}</h2>
+              <table class="table table-hover">
+                {% if rear_port_mappings %}
+                  <thead>
+                    <tr>
+                      <th>{% trans "Position" %}</th>
+                      <th>{% trans "Rear Port" %}</th>
+                    </tr>
+                  </thead>
+                {% endif %}
+                {% for mapping in rear_port_mappings %}
+                  <tr>
+                    <td>{{ mapping.front_port_position }}</td>
+                    <td>
+                      <a href="{{ mapping.rear_port.get_absolute_url }}">{{ mapping.rear_port }}:{{ mapping.rear_port_position }}</a>
+                    </td>
+                  </tr>
+                {% empty %}
+                  {% trans "No mappings defined" %}
+                {% endfor %}
+              </table>
+            </div>
             {% plugin_right_page object %}
         </div>
     </div>

netbox/templates/dcim/rearport.html

@@ -58,6 +58,7 @@
             </div>
             {% include 'inc/panels/custom_fields.html' %}
             {% include 'inc/panels/tags.html' %}
+            {% include 'dcim/inc/panels/inventory_items.html' %}
             {% plugin_left_page object %}
         </div>
         <div class="col col-12 col-md-6">
@@ -116,7 +117,29 @@
                     </div>
                 {% endif %}
             </div>
-            {% include 'dcim/inc/panels/inventory_items.html' %}
+            <div class="card">
+              <h2 class="card-header">{% trans "Port Mappings" %}</h2>
+              <table class="table table-hover">
+                {% if front_port_mappings %}
+                  <thead>
+                    <tr>
+                      <th>{% trans "Position" %}</th>
+                      <th>{% trans "Front Port" %}</th>
+                    </tr>
+                  </thead>
+                {% endif %}
+                {% for mapping in front_port_mappings %}
+                  <tr>
+                    <td>{{ mapping.rear_port_position }}</td>
+                    <td>
+                      <a href="{{ mapping.front_port.get_absolute_url }}">{{ mapping.front_port }}:{{ mapping.front_port_position }}</a>
+                    </td>
+                  </tr>
+                {% empty %}
+                  {% trans "No mappings defined" %}
+                {% endfor %}
+              </table>
+            </div>
             {% plugin_right_page object %}
         </div>
     </div>

netbox/utilities/relations.py

@@ -13,7 +13,7 @@ def get_related_models(model, ordered=True):
     related_models = [
         (field.related_model, field.remote_field.name)
         for field in model._meta.related_objects
-        if type(field) is ManyToOneRel
+        if type(field) is ManyToOneRel and not getattr(field.related_model, '_netbox_private', False)
     ]
 
     if ordered: