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| 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.