Non-Default Routing Table for EVPN Next-Hop Resolution

Junos devices maintain BGP underlay routes in the default routing table (inet.0 or inet6.0), where neighbor reachability is stored. Next-hop forwarding addresses are also resolved using the default routing table.

With an EVPN-VXLAN overlay network, traffic is sent through VXLAN tunnels between VXLAN tunnel endpoint (VTEP). For EVPN-VXLAN routes that span across geographic regions, the next-hop IP addresses for these routes can not be resolved using the default routing table. Rather, the routes required to reach these next hops exist in a specific VRF routing table.

Starting in Junos OS Release 26.2R1, Junos OS supports configuring a forwarding-context that maps BGP neighbors to a specific VRF routing instance. This allows Junos OS to resolve routes using the VRF routing table instead of the default inet.0 or inet6.0 table. By tagging EVPN-VXLAN routes with a color community and mapping each color to a VRF routing table, the device selects the appropriate routing table for route resolution

This feature allows you to have more granular control over how traffic is forwarded, particularly in scenarios with multiple VPNs, network slices, or service chaining. Junos OS supports all three VLAN service-type (VLAN Based, VLAN Bundle and VLAN Aware ) with the mac-vrf instance-type over both IPv4 and IPv6 underlay.

Note: EVPN-VXLAN Type 5 routes are not supported.

Benefits of Using a Non-Default Routing Table for EVPN Next-Hop Resolution

  • Enables you to have granular forwarding control of EVPN-VXLAN traffic involving multiple VPNs, network slices or service chaining across multiple geographic regions.

Configure a Non-Default Routing Table for Resolving EVPN-VXLAN Routes

The basic configuration steps for resolving EVPN-VXLAN Routes are listed below. The following sample configuration focuses on how to configure a single EVPN instance. Table 1 defines some of the key parameters that re used in the sample configuration:

Table 1: Key Parameters
Parameter Name or Value

EVPN Routing Instance

evpn-A

L3 VRF Routing Instance

VRF-1

Local VTEP IP Address

10.255.255.1

Remote VTEP IP Address

10.255.255.4

Color Community Tag

color:0:100

Resolution Scheme

rslv-color100

Import policy

BGP-EVPN-IMP

Resolution target

vrf-1.inet.0

When the Junos device receives EVPN route information, it applies an import policy (BGP-EVPN-IMP) that tags routes with color community information. When the device receives EVPN route information from a remote VTEP (10.255.255.4), it is tagged with the community color (color:0:100). Junos uses the resolution scheme (rslv-color100), to match the color community to direct the device to use a specific VRF routing table (vrf-1.inet.0).

  1. Create a BGP group with a color policy (BGP-EVPN-IMP) that will be applied to incoming BGP routes.
  2. Configure the forwarding context (VRF-1) that Junos uses to setup the reachability of BGP neighbors to the remote VTEP IP address (10.255.255.4) and uses the vrf-1 routing table.
  3. Configure the loopback interface (lo0) to support the VRF instance on the local VTEP interface. This enables Junos OS to advertise the local loopback IP to the remote VTEP Peer in the VRF context.
  4. Create the EVPN routing instance (evpn-A) with a mac-vrfinstance type.
  5. Configure the L3VRF routing instance (VRF-1).
  6. Configure the import policy (BGP-EVPN-IMP) to apply the community attributes (COLOR100) to EVPN routes coming from the remote VTEP IP address (10.255.255.4).
  7. Configure the resolution scheme (rslv-color100) that matches community attributes (color:0:100) to the routing table (VRF-1.inet.0).

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