Upstream traffic from the subscriber edge is either bridged or routed by the NVE. The EVPN service is located based on the VNI. The destination MAC address in the Ethernet frame is either the SF’s MAC address, in which case the traffic is bridged to the SF behind the NVE, or the destination MAC matches the local R-VPLS interface MAC address or single MAC address of the NVE. Then, the packet is routed (based on FIB lookup on the NVE) to the right SF.
Downstream traffic (network to subscriber edge to vas) after being processed by the VAS chain contains the NAT outside IP address in the IP destination address. SFs are configured with NVE as the default router. The packet is received on the NVE from the SF. A lookup is performed in the FIB on NVE (which contains IP prefixes populated by EVPN route type-5 updates). The next-hop IP address is the IP address of the ISA (GW-IP field in route type-5). An ARP and L2FDB lookup respectively provides the destination MAC address, and VXLAN VTEP and VNI. Traffic is VXLAN encapsulated and forwarded in the underlay toward the subscriber edge.