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.

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.

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.

• Address Families (address_family_ipv4, address_family_ipv6): Enable IPv4 and/or IPv6 routing within the VRF, each containing route target configuration.

• 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.
• address_family_ipv4, address_family_ipv6: Enable IPv4/IPv6 address families with route target configuration.
• 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.

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

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:
              import_route_targets: ["200:11"]
              import_route_targets_stitching: ["200:12"]
              export_route_targets: ["300:11"]
              export_route_targets_stitching: ["300:12"]
            address_family_ipv6:
              import_route_targets: ["200:13"]
              import_route_targets_stitching: ["200:14"]
              export_route_targets: ["300:13"]
              export_route_targets_stitching: ["300:14"]
            vpn_id: "36B:1234"