Bill, For what you are asking you can try something like the following: router bgp no sync network w.x.y.z (your network advertisement) ... neighbor A.A.A.A neighbor A.A.A.A filter-list 10 in neighbor A.A.A.A filter-list 15 out ... neighbor B.B.B.B neighbor B.B.B.B filter-list 20 in neighbor B.B.B.B filter-list 25 out ip as-path access-list 10 deny ip as-path access-list 10 permit ip as-path access-list 15 ^$ (permit your local stuff outbound) ip as-path access-list 20 deny ip as-path access-list 20 deny _$ (don't take anything with ISP A's AS number as the origination of the path) ip as-path access-list 20 permit .* (everything else) ip as-path access-list 25 ^$ (permit your local stuff outbound) With this config just remember if the link on router A fails you will not have a backup link to their AS path thru router B's link. I don't think you want to do this, you have a couple of options on configs. The best way to figure out what you want for redundancy and load balancing is to refer to Chapter 7 of Halabi's book Internet Routing Architectures. This sample has all the standard disclaimers. I would typically have a lot more in filter lists and access-lists but you can't include everything... Hope that helps. Ed ""Bill Carter"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I'm having trouble with this AS-Path situation. I have 2 routers (A and B) > running iBGP to each other. > > Each router has a single eBGP connection to a different service provider. > > ISP-A ISP-B > | | > A-------B > > From ISP A I am receiving partial routes, basically network within its AS. > > From ISP B I am receiving full internet routes. > > Here is the problem: The partial routes from ISP A are summarized, and the > routes from ISP may not be summarized. So my router A has an entry for > 12.0.0.0/8 and the AS path has 1 entry. Router B > receives the 12.0.0.0/8 through iBGP and also more specific routes from > ISP-B (12.20.1.0/24, 12.96.0.0/16). In router B the 12.X.X.X BGP entries > have the ISP-A AS# as the first entry in the AS-Path. > > Router B, because of the longest match rule, prefers the Router B-->ISP B > path for the more specific networks. > > I would like to use IP as-path filters to filter incoming updates from ISP-B > so not to learn networks originating from ISP-A AS#. > > What is the regular expression to do this?? > ip as-path access-list 20 deny ?????? ^as#_ _as#$ > > > From sho ip bgp > Network Next Hop > *> 12.0.0.0 A.A.A.A NEIGHBOR > *> 12.0.48.0/20 B.B.B.B NEIGHBOR > *> 12.0.252.0/23 B.B.B.B NEIGHBOR Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=16079&t=16068 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
