I was responsible for designing and implementing the Route Reflector (RR) control-plane architecture across our core backbone. The infrastructure consisted of a centralized MPLS core, multiple PE routers deployed across regional Points of Presence (PoPs), and CE routers at customer branches throughout Nigeria.
The primary challenge was iBGP scalability: a full mesh between all PE routers would require a rapidly growing number of neighborships (n(n–1)/2). To solve this, I designed a redundant and geographically distributed Route Reflector topology.
These locations were chosen to ensure geographic redundancy, faster convergence during regional outages, and control-plane resilience. Loopback interfaces were advertised via OSPF Area 0, and RRs maintained control-plane-only functionality and no VRF or CE configurations to preserve CPU resources and isolate fault domains.
On each RR, I configured iBGP VPNv4 peering using peer groups, enabling:
- send-community extended for Route Target propagation.
- route-reflector-client for efficient route distribution.
Each PE formed iBGP sessions with both RRs using loopback interfaces. I explicitly avoided peering the two RRs with each other, relying on BGP originator-ID and cluster-ID to prevent routing loops. Each RR reflected only routes from its direct clients, maintaining deterministic control-plane behavior.
To validate the deployment, I:
- Verified VPNv4 route visibility on each PE.
- Confirmed correct RT and RD propagation.
- Ensured successful VRF route import/export.
- Tested CE-to-CE reachability across VRFs.
The result was a highly scalable, loop-free, and resilient iBGP control-plane:
- Reduced iBGP complexity from multiple neighborships to 2 per PE.
- Ensured full VPNv4 route reachability across all customer sites.
- Enabled clean control/data plane separation, improving stability and simplifying troubleshooting.
- This RR design allowed the MPLS backbone to scale seamlessly as new PEs and customers were added across regions.
Top comments (0)