Dell EMC SmartFabric OS10 User Guide Release 10.5.0

Asymmetric IRB routing

In asymmetric IRB routing, IRB routing is performed only on ingress VTEPs. Egress VTEPs perform L2 bridging in the tenant subnet.

An ingress VTEP directly routes packets to a destination host MAC address in the destination virtual-network VNI. An egress VTEP only bridges packets to a host by removing the VXLAN header and forwarding a packet to the local Layer 2 domain using the VNI-to-VLAN mapping.

The ingress VTEP is configured with all destination virtual networks, and has the ARP entries and MAC addresses for all destination hosts in its hardware tables. Each VTEP learns the host MAC and MAC-to-IP bindings using ARP snooping for local addresses and type-2 route advertisements from remote VTEPs.

For VXLAN BGP EVPN examples that use asymmetric IRB, see Example: VXLAN with BGP EVPN and Example: VXLAN BGP EVPN — Multiple AS topology.