Tag :: EVPN Gateway

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 is used to connect a Layer 3 EVPN VXLAN network to an Adaptive Virtual Topology (AVT) WAN network using dynamic path selection (DPS) tunnels. One or a pair of WAN routers are configured to serve as the VXLAN gateway. On the control plane, the configured VXLAN gateway handles EVPN IP-PREFIX route exchanges between the VXLAN network and the WAN network. On the data plane, the configured VXLAN gateway decapsulates the VXLAN packets received from the VXLAN network and encapsulates them into the DPS tunnels and sends them to the AVT WAN network. 

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.

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.