Solved: prefix-list vs access-list and these two articles

zillah2004 · ‎09-25-2006

I have read in CCNP curriculum that Cisco says :

" 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 :

1- Significant performance improvement in loading and route lookup of large lists.

2- Support for incremental updates. Filtering by way of extended access lists does not support incremental updates.

3- A more user friendly command-line interface.

4- Greater flexibility ".

But when I read the article below , I could not figure out what does he mean :

" Unlike the IP access-list, which was designed to match traffic, the IP prefix-list was designed specifically with network reachability information in mind ".

Regards

Harold Ritter · ‎09-25-2006

What this article means is that the prefix-list would be used at the control plane level rather than the forwarding plane level.

For instance you wouldn't use a prefix-list to filter traffic (forwarding plane) as you do with an ACL. The prefix-list is mainly used for route filtering (control plane).

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

View solution in original post

Richard Burts · ‎09-26-2006

This link is to a good article by Russ White in the Internet Protocol Journal which includes some discussion of control plane and data plane (forwarding plane). I hope that it will help you to understand these concepts.

http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_7-1/high_availability_routing.html

HTH

Rick

HTH

Rick