nanog mailing list archives

Re: distinguishing eBGP from show ip BGP


From: Mark Tinka <mark.tinka () seacom mu>
Date: Wed, 11 Mar 2015 21:50:04 +0200



On 11/Mar/15 21:42, Reza Motamedi wrote:
What I ultimately want to determine, is the location of the AS connection. I know for example the router is in, say LA. If hot potato lets me to send the packet to the neighbor AS then they have an AS connection in LA, right?

Going back to my example does the fact that the entry does not have 'i' mean that I can send it to AS2828 on the next hop.

Yes - the route was not learned via iBGP; which means it was learned via eBGP.

But that is just routing. It does not necessarily paint the forwarding topology (remember, routing and forwarding are two different operations).

The next-hop may be local to "this router", but it could also be a tunnel (which may be cold-potato forwarded before exiting the local AS), or the eBGP session could be eBGP Multi-Hop.

Mark.


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