BGP Notes – Route Reflectors

  • Route reflectors remove the requirement of having a full mesh iBGP network.
  • Any iBGP route a router reflector learns is sent to all route reflector clients.
    • Non-client iBGP neighbors do not get the new route per iBGP rules.
  • RR clients are configured like normal iBGP routers.
    • All RR client config is done on the route reflector.
  • RRs and clients are part of a cluster.
    • RRs in each cluster must be neighbors with each other.
    • Each cluster RR appends the cluster ID to the CLUSTER_ID PA; this is used similarly to AS_CONFED_SEQ.
  • The ORIGINATOR_ID PA is set by and preserved by the RR.
    • If a route contains the ORIGINATOR_ID of the receiving router, the update is ignored.
  • Only best routes are passed to RR clients and non-client neighbors.
router bgp 123
 no synchronization
 bgp cluster-id 1
 neighbor remote-as 123
 neighbor route-reflector-client

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