Re: bgp soo and route-maps

One big question, are you receiving prefixes from the other end? Check it
and see why.

On Fri, Sep 10, 2010 at 9:49 AM, Piotr Malarski <piotr.malarski.99_at_gmail.com
> wrote:

> Hello,
>
> I need a clarification about bgp soo. In the example below R4 and R5 are
> connected with two links 10.1.45.0/24 and 10.1.100.0/24:
>
> R4 (PE)===========R5 (CE)
> AS65001 AS6015
>
> R5 (CE) advertises network 5.0.0.0.
> The problem is that R5 (CE) receives it's own route redistributed back from
> R4:
> R5#
> R5#sh ip bgp | b Network
> Network Next Hop Metric LocPrf Weight Path
> * 5.0.0.0 10.1.100.4 0 65001 65001 i
> *> 0.0.0.0 0 32768 i
> R5#
>
> To remediate, SOO is configured on R4:
>
> 1. Route-map is configured:
>
> route-map SOO-IN permit 10
> set extcommunity soo 1:100
>
> 2. Route map is applied:
>
> router bgp 65001
> !
> address-family ipv4 vrf CB
> neighbor 10.1.45.5 route-map SOO-IN in
> neighbor 10.1.100.5 route-map SOO-IN in
>
> AT THIS POINT the problem is solved. R5 does not contain it's own route
> back
> from R4:
>
> R5#sh ip bgp | b Network
> Network Next Hop Metric LocPrf Weight Path
> *> 5.0.0.0 0.0.0.0 0 32768 i
>
> HOWEVER the workbook goes extra few steps and confiures additional
> filtering
> on PE OUT to CE:
>
> ip extcommunity-list 1 permit soo 1:105
> route-map SOO-OUT deny 10
> match extcommunity 1
> route-map SOO-OUT permit 99
> !
> router bgp 65001
> !
> address-family ipv4 vrf CB
> neighbor 10.1.45.5 route-map SOO-OUT out
> neighbor 10.1.100.5 route-map SOO-OUT out
> My question is why second route-map OUT is configured on PE. It looks like
> only marking on PE incoming routes with ext community soo works OK.
>
>
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