MPLS VPN BGP Route Reflector

Introduction

BGP Route Reflection for MPLS VPN is similar to regular BGP. Each address-family can have a different route reflector.

MPLS VPN BGP Route Reflector

  • Dedicated Router Reflectors will not any any attached VRFs, but they will import all VPNv4 prefixes for all route-targets. These prefixes will not be installed in the cef table just RIB.
  • By default PEs will receive all VPNv4 routes, but will deny any that don't match import route targets locally defined. Using debugs (debug bgp vpnv4 unicast updates) message like "DENIED due to: extended community not supported" will appear.
  • Just like in IPv4 BGP route reflection, next-hop is not modified, if it was PE would be selecting a different LSP. This comes into play with Inter-AS functionality.
  • Retain Route Target can be used to filter which RT to retain in route-reflectors. VPNv4 prefixes will still be advertised, but no reflected and retained locally.

Additional Resources

BGP Route Reflection
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