[cisco-bba] BGP/ADSL aggreagation

Mark Tohill Mark at u.tv
Tue Jul 26 08:19:27 EDT 2005


We have secured our own AS no. with RIPE.

We hope to change from iBGP (running same AS as our current sole
upstream provider) to eBGP, since we will soon be multi-homing to 2

Does this not make sense?

I'm glad to hear the possibility of running BGP on an LNS will not be
the first time it's been implemented. :)



-----Original Message-----
From: Thomas Bridge [mailto:thomas at wibble.to] 
Sent: 26 July 2005 13:12
To: Mark Tohill
Cc: cisco-bba at puck.nether.net
Subject: Re: [cisco-bba] BGP/ADSL aggreagation

On Tue, Jul 26, 2005 at 12:09:51PM +0100, Mark Tohill wrote:
> We have the following scenario:
> We have two PoP's, PoP1 and PoP2, providing ADSL aggregation in both.
> Both PoP1 and PoP2 have an edge router running iBGP with our upstream
> provider, which happens to be the same provider (same AS), peering at
> their two same-city PoP's.
> The plan is to move our ADSL aggregation in PoP2 to another provider
> same city, and maintain a link between the BAS and our PoP2 edge. PoP2
> has non-contiguous IP space from our /16.
> Question(s): 
> 1. Does it make sense to run eBGP across our infrastructure? IMHO I
> suspect it does, since we are multi-homing, of sorts at least.

Um - how can you run eBGP when you're running iBGP to your provider? 
Are you using two seperate AS numbers in your network?
> 2. Can we run eBGP/iBGP on our BAS terminating our ADSL users. I'd
> imagine this would be frowned upon in Cisco, or has anyone tried it?

I've done it - with a full routing table to boot.   I ran it is an RR
to fix a problem with out internal design, but it wasn't optimal.


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