MPLS L3VPN on Cisco IOS-XE: VRF, MP-BGP, and Label Forwarding Configuration Guide
New post on ignaonline.com — this one is for the network engineers.
MPLS L3VPN on Cisco IOS-XE: VRF, MP-BGP, and Label Forwarding Configuration Guide
We walk through a complete MPLS L3VPN lab build from scratch: VRF definitions with route distinguishers and route targets, LDP for label distribution, MP-BGP with VPNv4 address family for carrying VPN routes between PE routers, and PE-CE BGP for customer connectivity. Every step is validated with real IOS-XE show commands — including end-to-end ping verification and confirmed VRF isolation between customers.
We also cover the four most common failure modes (LDP not forming, missing VPNv4 routes, routes present but ping fails, PHP behavior) and common production pitfalls like BGP AS_PATH loops, MTU overhead, OSPF backdoor links, and VRF-aware management services.