VRF

VRF (Virtual Routing and Forwarding) enables network virtualization by creating isolated routing and forwarding instances within a single physical device. It supports MPLS Layer 3 VPNs, multi-tenancy, and network segmentation through separate routing tables, forwarding tables, and interfaces for each VRF instance. VRF provides comprehensive control over route import/export policies using route targets, route distinguishers for unique route identification, and supports both IPv4 and IPv6 address families with granular policy control.

Diagram

Classes

configuration (iosxe.devices)

Name	Type	Constraint	Mandatory	Default Value
vrfs	List	`[vrfs]`	No

vrfs (iosxe.devices.configuration)

Name	Type	Constraint	Mandatory
name	String		Yes
description	String		No
route_distinguisher	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	No
address_family_ipv4	Boolean	`true`, `false`	No
address_family_ipv6	Boolean	`true`, `false`	No
vpn_id	String	Regex: `^[0-9a-fA-F]{1,6}:[0-9a-fA-F]{1,8}$`	No
import_route_targets	List	`[import_route_targets]`	No
export_route_targets	List	`[export_route_targets]`	No
ipv4_route_target_imports	List	`[ipv4_route_target_imports]`	No
ipv4_route_target_exports	List	`[ipv4_route_target_exports]`	No
ipv6_route_target_imports	List	`[ipv6_route_target_imports]`	No
ipv6_route_target_exports	List	`[ipv6_route_target_exports]`	No

import_route_targets (iosxe.devices.configuration.vrfs)

Name	Type	Constraint	Mandatory
value	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	Yes
stitching	Boolean	`true`, `false`	No
ipv4	Boolean	`true`, `false`	No
ipv6	Boolean	`true`, `false`	No

export_route_targets (iosxe.devices.configuration.vrfs)

Name	Type	Constraint	Mandatory
value	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	Yes
stitching	Boolean	`true`, `false`	No
ipv4	Boolean	`true`, `false`	No
ipv6	Boolean	`true`, `false`	No

ipv4_route_target_imports (iosxe.devices.configuration.vrfs)

Name	Type	Constraint	Mandatory	Default Value
value	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	Yes
stitching	Boolean	`true`, `false`	No

ipv4_route_target_exports (iosxe.devices.configuration.vrfs)

Name	Type	Constraint	Mandatory	Default Value
value	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	Yes
stitching	Boolean	`true`, `false`	No

ipv6_route_target_imports (iosxe.devices.configuration.vrfs)

Name	Type	Constraint	Mandatory	Default Value
value	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	Yes
stitching	Boolean	`true`, `false`	No

ipv6_route_target_exports (iosxe.devices.configuration.vrfs)

Name	Type	Constraint	Mandatory	Default Value
value	String	Regex: `^((\d{1,5}:\d{1,10})\|((\d{1,3}\.){3}\d{1,3}:\d{1,10})\|([\da-fA-F]{1,8}:\d{1,10}))$`	Yes
stitching	Boolean	`true`, `false`	No

By segmenting the network into multiple VRFs, you achieve traffic isolation, multi-tenancy, and efficient resource utilization, making VRF essential for service providers and enterprises requiring routing separation.

VRF Parameters

Key Components:

VRF Name (name): The unique identifier for the VRF instance.
Description (description): A text description for the VRF, useful for documentation and operational clarity.
Route Distinguisher (route_distinguisher): Uniquely identifies routes within the MPLS VPN domain, preventing overlap.
Route Targets (import_route_targets, export_route_targets): Control which routes are imported to or exported from the VRF, supporting flexible policy and stitching.
Address Families (address_family_ipv4, address_family_ipv6): Enable IPv4 and/or IPv6 routing within the VRF.
VPN ID (vpn_id): Identifies the VPN for interoperability and management.
Interface Association (interface): Associates physical or logical interfaces with the VRF for traffic isolation.

Key Parameters Briefly Explained:

name: Sets the VRF instance name.
description: Adds a description to the VRF.
route_distinguisher: Configures the unique route identifier.
import_route_targets, export_route_targets: Define route import/export policies.
address_family_ipv4, address_family_ipv6: Enable IPv4/IPv6 address families.
vpn_id: Sets the VPN identifier.
interface: Associates interfaces with the VRF.

You can use these VRF parameters to define isolated routing environments on your network device. Customize the name, route distinguisher, route targets, and interface associations to fit your network’s segmentation and multi-tenancy needs. Adjusting these parameters lets you tailor traffic isolation and routing policies for different network domains.

Sample Configuration

The following configuration describes how to set up a VRF instance on a Cisco IOS-XE device. It includes defining the VRF, setting its route distinguisher, configuring route targets for import and export, enabling address families, and associating an interface for traffic isolation.

ip vrf definition VRF-PROD
 description Production VRF
 rd 200:1
 route-target export 200:10
 route-target export 300:10
 route-target import 200:10
 route-target import 300:10
 address-family ipv4
  route-target import 200:11 stitching
  route-target export 300:11
 exit-address-family
 address-family ipv6
  route-target import 200:13
  route-target export 300:13 stitching
 exit-address-family
!
interface GigabitEthernet0/1
 ip vrf forwarding VRF-PROD
 ip address 10.0.0.1 255.255.255.0

Example YAML Code

The following YAML code sets up a VRF instance on an IOS-XE device, specifying its name, description, route distinguisher, route targets for import and export, and address family configurations for both IPv4 and IPv6.

iosxe:
  devices:
    - name: Device1
      configuration:
        vrfs:
          - name: "VRF-PROD"
            description: "Production VRF"
            route_distinguisher: "200:1"
            address_family_ipv4: true
            address_family_ipv6: true
            vpn_id: "36B:1234"
            import_route_targets:
              - value: "200:10"
                stitching: false
                ipv4: true
                ipv6: true
              - value: "300:10"
                stitching: false
                ipv4: true
                ipv6: true
            export_route_targets:
              - value: "200:10"
                stitching: false
                ipv4: true
                ipv6: true
              - value: "300:10"
                stitching: false
                ipv4: true
                ipv6: true
            ipv4_route_target_imports:
              - value: "200:11"
                stitching: true
            ipv4_route_target_exports:
              - value: "300:11"
                stitching: false
            ipv6_route_target_imports:
              - value: "200:13"
                stitching: false
            ipv6_route_target_exports:
              - value: "300:13"
                stitching: true