9.8 BGP Route Filtering and Policy Routing  
  9.8.4 The ip prefix-list command  
Use prefix lists as an alternative to access lists with many BGP route filtering commands. The advantages of using prefix lists rather than access lists include the following:
  • Significant performance improvement in loading and route lookup of large lists.
  • Support for incremental updates. Filtering by way of extended access lists does not support incremental updates.
  • A more user friendly command-line interface.
  • Greater flexibility.

Define a prefix list before applying it as a route filter. The Cisco IOS allows a very flexible configuration procedure, where each statement can be assigned its own sequence numbers.

To define a prefix list, use the ip prefix-list command, which has the syntax shown in Figure . Figure describes the parameters that are used with this command.

 

Lab Activity

e-Lab Activity: ip prefix-list Command

This lab is to use prefix lists as an alternative to access lists with many BGP route filtering commands.