[178850] in North American Network Operators' Group
Re: distinguishing eBGP from show ip BGP
daemon@ATHENA.MIT.EDU (Mark Tinka)
Wed Mar 11 15:50:10 2015
X-Original-To: nanog@nanog.org
Date: Wed, 11 Mar 2015 21:50:04 +0200
From: Mark Tinka <mark.tinka@seacom.mu>
To: Reza Motamedi <motamedi@cs.uoregon.edu>
In-Reply-To: <CACGuEhHsRf0cRYkXA-Xmiwg3ziErE=W-=vHno1HTuZ-F4Yph_g@mail.gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
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.
