L3VPN over SR MPLS

L3VPN over SR‐MPLS has gained considerable attention as it combines the flexibility of Segment Routing with the scalability of traditional MPLS. Operators can steer traffic more efficiently while reducing protocol overhead by assigning segment identifiers (SIDs) within the control plane. This architecture suits a variety of scenarios, including enterprise WAN connectivity, inter‐data‐center links, and mobile backhaul applications where traffic engineering and high availability are essential.
Our testing focused on verifying that L3VPN services function consistently across two separate topologies, each leveraging different interior gateway protocols: one design used IS‐IS with two spine nodes, and the other used OSPF with a single spine node. 

In both cases, the initial step was to validate the underlying control plane, ensuring that the devices were distributing Segment Routing labels correctly and that BGP sessions exchanged VPN routes without error. Foundational checks confirmed proper label installation. Subsequently, we activated L3VPN services and injected IPv4 and IPv6 traffic.
We checked the routers' routing tables for the next hops and label bindings. Then, we generated traffic through all links to detect packet loss or route inconsistencies. We didn't detect packet loss in any of the flows, which shows that the SR-MPLS forwarding paths are reliable. The setup successfully handled IPv4 and IPv6 data streams, demonstrating multi-protocol forwarding capability.
The positive results from these tests demonstrate that the test setup supports the scalability and robustness needed for future services and establishes a solid foundation for further testing.

Note: The traffic generator was connected via a switch, enabling simultaneous communication with all PE devices.