From: ying chang (ying_c@xxxxxxxxxxx)
Date: Mon Jun 03 2002 - 09:20:51 GMT-3
How about ^\(*\)$? That should let you get the confederations you want to
filter.
>From: Dustin.Yates@ercgroup.com
>Reply-To: Dustin.Yates@ercgroup.com
>To: ccielab@groupstudy.com
>Subject: AS-Path Filter with Confederation
>Date: Sun, 2 Jun 2002 22:55:30 -0500
>
>I'm trying to filter routes sent to an EBGP neighbor to prevent the local
>AS
>from being used as a transit AS. The classic example allows for you to use
>an as-path filter with ^$ as the regular expression on the outgoing filter
>list. What if the AS is a confederation with multiple sub-AS's?
>
>From the 'sh ip bgp' command below, I want to filter routes I send to my
>neighbor at AS 130. Only one route is a candidate for filtering that is
>originated in AS 1000:
>
>R6#sh ip bgp
>BGP table version is 11, local router ID is 155.10.6.6
>Status codes: s suppressed, d damped, h history, * valid, > best, i -
>internal
>Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
>*> 155.10.0.0/24 155.10.135.3 20 100 0 (250) i
>*> 155.10.25.0/24 155.10.5.5 0 100 0 (250) i
>*> 155.10.44.0/24 155.10.45.4 6892 100 0 (250) i
>*> 155.10.139.0/24 155.10.135.3 58 100 0 (250) i
>*> 198.6.48.0/21 155.10.2.2 100 0 (250 8) i
>*> 198.6.53.0 155.10.2.2 0 100 0 (250 8) 1000 i
>***This is the route I want to filter***
>
>Ok, a couple of sample 'sh ip bgp regexp' commands shows that I can't
>filter
>this route with a simple expression:
>R6#sh ip bgp regexp 8
>BGP table version is 11, local router ID is 155.10.6.6
>Status codes: s suppressed, d damped, h history, * valid, > best, i -
>internal
>Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
>*> 198.6.48.0/21 155.10.2.2 100 0 (250 8) i
>*> 198.6.53.0 155.10.2.2 0 100 0 (250 8) 1000 i
>
>R6#sh ip bgp regexp 250
>BGP table version is 11, local router ID is 155.10.6.6
>Status codes: s suppressed, d damped, h history, * valid, > best, i -
>internal
>Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
>*> 155.10.0.0/24 155.10.135.3 20 100 0 (250) i
>*> 155.10.25.0/24 155.10.5.5 0 100 0 (250) i
>*> 155.10.44.0/24 155.10.45.4 6892 100 0 (250) i
>*> 155.10.139.0/24 155.10.135.3 58 100 0 (250) i
>*> 198.6.48.0/21 155.10.2.2 100 0 (250 8) i
>*> 198.6.53.0 155.10.2.2 0 100 0 (250 8) 1000 i
>R6#sh ip bgp regexp ^$
>
>R6#sh ip bgp regexp ^250$
>
>R6#sh ip bgp regexp ^250 8$
>
>R6#sh ip bgp regexp ^(250 8)$
>
>R6#
>
>My goal is to filter this with a generic statement such as ^$. Or, even
>one
>that would use the confederation peers (in this case 250, 8, & 6). The
>confederation id is 22. What is the trick to getting this route to filter
>as part of a generic outgoing filter list-- without targeting specific
>external AS's such as AS 1000? I know there are other ways to do this, but
>I'm trying strictly to do this with an as-path filter. Pointers to CCO
>documents that address path filters with confederations such as this would
>be greatly appreciated.
This archive was generated by hypermail 2.1.4 : Tue Jul 02 2002 - 08:12:22 GMT-3