© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Module Summary BGP is a path-vector routing protocol that allows routing policy decisions at the AS level to be enforced. BGP forms EBGP relationships with external neighbors and IBGP with internal neighbors. All routers in the transit path within an AS must run fully meshed IBGP. When BGP is properly configured, it will establish a neighbor relationship, set the next-hop address, set the source IP address of a BGP update, and announce the networks to other BGP routers. BGP performs a multistep process when selecting the best path to reach a destination. BGP can manipulate path selection to affect the inbound and outbound traffic policies of an AS. Route maps can be configured to manipulate the local preference and MED BGP attributes.

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v3.06-2