Re: eBGP, iBGP, injecting networks

[James <haesu () towardex com>]

        greetings,

        from what you are saying, it appears you just got two routers
        in the equation..

        i say it's just easier for you to merge both routers into single
        asn and run an igp in between. announce your aggregate(s) at both
        routers afterwards, now that they are in same asn. so no inconsistant-AS
        issue there

        if your transit provider is not being cooperative fast enough,
        temporarily use 'neighbor a.b.c.d local-as oldasn'. then you can get rid
        of that once they update their end.

        as far as announcing same space between two diff. asn's causing problems..
        yes and no.
        as long as your FIB entries for the most specific are pointing to working
        path on both routers, you won't run into technical problem. but this is
        inconsistant-AS issue which is often perceived as 'not cool.' IMHO, its
        ad-hoc solution


-J


-- 
James Jun (formerly Haesu)
TowardEX Technologies, Inc.
1740 Massachusetts Ave.
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On Fri, Feb 20, 2004 at 02:41:46PM -0800, isaac () ravengate net wrote:
> greetings list,
>
> hoping someone can hook me up on the right way to do this.    
>
> ---
>
> we have two ASN's we control.
>
> we have two border/edge routers (1 in each ASN) that talks to a
> different backbone provider.
>
> the two border routers peer with eachother over eBGP and also are in
> the same OSPF process.  (we are working to merge them into the same
> BGP ASN)
>
> my question is this:
>
> how do we achieve router redundancy between these two routers?
>
> currently if we lose a transit link, the traffic will flow fine out
> the other pipe.
>
> but we don't have BGP network statements in router 2 that exist in
> router 1 and we don't have BGP network statements in router 1 that
> exist in router 2.
>
> so the routes injected into BGP from router 1 will get withdrawn right
> if router 1 dies?
>
> is it a problem to announce the same networks from two different eBGP
> peers to two different upstreams?
>
> ------
>
> if you are still reading, thanks!
>
> to clearify some more-
>
> current setup:
>
> current setup:
>
> ASN 1 (we're not Genu!ty- just using for an example)
>
> :)
>
> ASN 1 injects all of its own space and announces this space to
> Above.net and ASN 2
>
> ASN 2 injects all of its own space and announces this space to Savvis
> and ASN 1.
>
> so stuff out on the net looks like:
>
> 1 6461 etc etc
>
> and
>
> 1 2 6347
>
> -------
>
> 2 6347 etc etc
>
> and
>
> 2 1 6461 etc etc
>
> -------
>
> so, you see we are prepending on of our AS's on the way out.
>
> the problem is tho, we only have 1 router in each respective Autonmous
> System injecting address space.  if we lose that router, we lose
> announcing that ASN's space.
>
> is it totally going to cause probs to have routes originating from two
> different AS's?  routing loops would be a real drag.
>
> what about having an iBGP router in AS 1 inject the same space as the
> border router in AS 1?  this other router also peers with AS 2....
>
> thanks a lot!
> jg