From: Tarun (tarun.ccie@gmail.com)
Date: Thu Apr 17 2008 - 23:30:58 ART
Option 1 - Situation when you can use both a prefix-list & a access-list.
Let's say if you want to match any class C prefix - You can use an
access-list like this for this purpose 'ip access-list 1 permit 192.0.0.0
31.0.0.0' - This would match any class C prefix irrespective of it's subnet
mask length.
The same can be done using a prefix-list 'ip prefix CLASS_C permit
192.0.0.0/3 le 32
Option 2 - Situation when you can use only a prefix-list.
Let's say you want to match only the class C prefixes with a subnet mask of
length 24bits to 32bits - You cannot match on subnet mask length in an
access-list.
The prefix list used in this situation would be 'ip prefix CLASS_C permit
192.0.0.0/3 ge 24 le 32'
Conclusion - Prefix lists are much more stronger than access-lists.
Access-lists can match only on prefix patterns, they do not match the subnet
length at all.
Prefix-lists can match both on prefix patterns & subnet mask length.
http://ccienotes.blogspot.com/2007/08/ip-prefix-list.html
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This archive was generated by hypermail 2.1.4 : Thu May 01 2008 - 08:25:51 ART