TOI Author :: Xuan Qi

This feature supports an alternative L3 EVPN gateway mechanism using multi-domain L3 VRF instead. A multi-domain IP VRF allows configuring not only the local domain route distinguisher (RD) and route targets (RT), but also the remote domain route distinguisher and route targets on a DCI gateway.

This feature adds all-active (A-A) multihoming support on the multi-domain EVPN VXLAN-MPLS gateway. It allows L2 and L3 ECMP to form between the multihoming gateways on the TOR devices inside the site and on the gateways in the remote sites. Therefore, traffic can be load-balanced to the multi-homing gateway and redundancy and fast convergence can be achieved.

EVPN gateway support for all-active (A-A) multihoming adds a new redundancy model to our multi-domain EVPN solution introduced in [1]. This deployment model introduces the concept of a WAN Interconnect Ethernet Segment identifier (WAN I-ESI). The WAN I-ESI allows the gateway’s EVPN neighbors to form L2 and L3 overlay ECMP on routes re-exported by the gateways. The identifier is shared by gateway nodes within the same domain (site) and set in MAC-IP routes that cross domain boundaries.

This feature extends the multi-domain EVPN VXLAN feature introduced to support interconnect with EVPN MPLS networks. The following diagram shows a multi-domain deployment with EVPN VXLAN in the data center and EVPN MPLS in the WAN. Note that this is the only supported deployment model, and that an EVPN MPLS network cannot peer with an EVPN MPLS network.

In EOS 4.22.0F, EVPN VXLAN all active multi homing L2 support is available. A customer edge (CE) device can connect to