© 2005 Cisco Systems, Inc. All rights reserved. BGP v Module Summary Service providers use an IGP to carry internal routes and to provide optimal routing between POPs, the information that is needed for IBGP sessions to be established, and the addresses that are required for BGP next-hop resolution. Route reflectors enable BGP routing information to be distributed in a fashion that does not require a physical fully meshed network. Route reflector clusters can be built in hierarchies. A router that is a route reflector in one cluster can act as a client in another cluster.

© 2005 Cisco Systems, Inc. All rights reserved. BGP v Module Summary (Cont.) There are only two Cisco IOS commands that are used to configure route reflectors: bgp cluster-id and neighbor ip- address route-reflector-client. BGP confederations are a scalability mechanism that relaxes the IBGP full-mesh requirements of classic BGP. BGP confederations are configured by specifying the confederation identifier and other member-AS peers.

© 2005 Cisco Systems, Inc. All rights reserved. BGP v3.26-3