© 2005 Cisco Systems, Inc. All rights reserved. BGP v Module Summary BGP has reliable transport provided by TCP, a rich set of metrics called BGP path attributes, and scalability features such as batched updates that make it suitable for very large networks. Configured BGP neighbors establish a TCP session and exchange the BGP Open message, which contains the parameters that each BGP router proposes to use. Some path attributes are well-known and should be recognized by every BGP implementation. Some of the well-known attributes, such as AS-path, next-hop, and origin, are mandatory and have to be present in every BGP update.

© 2005 Cisco Systems, Inc. All rights reserved. BGP v Module Summary (Cont.) The route selection process takes into account various BGP attributes that are attached to the route, as well as local decisions. When you are configuring BGP neighbors, you will enable the BGP routing protocol process, establish neighbors, and advertise local routes. To ensure that basic BGP configurations are operating correctly, there are a number of Cisco IOS commands to monitor the status of BGP, neighbor connections, and the BGP table, as well as to troubleshoot the most common BGP session startup issues.

© 2005 Cisco Systems, Inc. All rights reserved. BGP v3.21-3