Route Filtering and Attribute Manipulation

Route filtering and attribute manipulation are the basis of implementing BGP policies. This section describes the following:

  • BGP route maps

  • Prefix lists

  • Identifying and filtering routes based on the NLRI

  • Identifying and filtering routes based on the AS_PATH

In order for new BGP policies such as attribute manipulation or filtering to be applied, a fresh set of the relevant routes must be presented to the Input Policy Engine. This can be accomplished in a number of ways. The brute-force way is to simply reset the BGP session by using the following command:

clear ip bgp [* | address | peer-group][soft [in|out]]

However, soft reconfiguration or BGP Route Refresh provide solutions that are ...

Get Internet Routing Architectures, Second Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial