[j-nsp] iBGP impacting eBGP

[Jad KAROUT]

Hi everyone,

thanks for your suggestions.

The problem's been solved following Chris's suggestion on using  
aggregate routes.

the iBGP session was originally used by the M7i to advertise some  
outer prefixes to its internal peer, and the M7i was not learning  
anything from its internal peer, hence my original confusion as to  
why the removal of the now useless iBGP session impacted the eBGP  
sessions.

Jad.





Le 5 nov. 07 à 17:08, Jad KAROUT a écrit :

> I'm encountering a problematic issue on our juniper M7i.
>
> We use this router to announce our prefix to the world via two
> carriers (ts and c&w). This router also establishes an iBGP link with
> another one of our routers.
>
> So the BGP configuration goes something like this :
>
> jad at JUNIPER-BGP> show configuration protocols bgp
>
> traceoptions {
>      file bgp.log size 1m files 5;
>      flag normal;
>      flag state;
> }
> log-updown;
> group T-S {
>      type external;
>      authentication-key "$9$wrsoGUjkf5Q-dXtc.f5yreKx-oJDi.5lKjk"; ##
> SECRET-DATA
>      export PREFIX_OUT;
>      neighbor IP_TS {
>          peer-as TS_AS;
>      }
> }
>
> group XTS {
>      type internal;
>      local-address IP_J;
>      neighbor IP_RB {
>          export DONT_ADVERTISE;
>      }
> }
>
> group CW {
>      type external;
>      authentication-key "$8*xtdpHKJHJKL-.hjkGUreKx-oJDi.ppWJoi"; ##
> SECRET-DATA
>      export PREFIX_OUT;
>      neighbor IP_CW {
>          peer-as CW_AS;
>      }
> }
>
>
> However due to changes in our architecture, the iBGP session is no
> longer needed and must be removed. I tried to do that by deleting the
> corresponding group in the BGP conf as it is now useless.
> However, the second i commit that change, the M7i stops announcing
> our prefix to the two eBGP peers.
>
> I don't understand how removing an iBGP session can impact eBGP
> sessions ?
>
> Any idea anyone ?
>
> Thanks.
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