In real-world networks, it is common to have multiple transport and EVPN domains distributed across different geographic locations. This year, we successfully recreated such a scenario in our test environment. Our topology consists of five interconnected domains: EVPN-SR-MPLS, EVPN-VXLAN, and IPVPNv4. The two VXLAN domains demonstrate VXLAN stitching. The two SR-MPLS domains interconnected via a VXLAN domain showcase the EVPN-SR-MPLS and EVPN-VXLAN Gateway features. The IPVPNv4 domain demonstrates EVPN IPVPN interworking. This multidomain topology covers several common scenarios in real-world use cases.

In our test, we enabled Interconnect Ethernet Segment (I-ES) between EVPN SR-MPLS and EVPN VXLAN to facilitate overlay interworking. To prevent route loops, Domain Path (D-PATH) was also activated between these three domains. Additionally, the Unknown MAC Route (UMR) feature was configured on the EVPN SR-MPLS and EVPN VXLAN gateway, allowing the handling of unknown unicast traffic by setting the destination MAC address to all 0 and forwarding such packets to the gateway.

Finally, we generated full-mesh unicast traffic using Keysight IxNetwork across all domains, evaluating both routing and bridging scenarios. Every packet was delivered end-to-end without loss, confirming the successful operation of the complex multidomain interworking setup.