[178847] in North American Network Operators' Group
Re: distinguishing eBGP from show ip BGP
daemon@ATHENA.MIT.EDU (Mark Tinka)
Wed Mar 11 15:30:54 2015
X-Original-To: nanog@nanog.org
Date: Wed, 11 Mar 2015 21:30:46 +0200
From: Mark Tinka <mark.tinka@seacom.mu>
To: Reza Motamedi <motamedi@cs.uoregon.edu>, nanog@nanog.org
In-Reply-To: <CACGuEhH+5DeRmb=c=+nnHQEwVYXPmN8h4tm8DaathjhrcHY9UQ@mail.gmail.com>
Errors-To: nanog-bounces@nanog.org
On 11/Mar/15 21:22, Reza Motamedi wrote:
>
> Thanks Mark for the reply. Let me try to check what I understood is
> correct. Does the 'i' on the left (status code) only shows whether the
> prefix belongs to this AS?
>
Status-code "i" just means the entry was learned by "this" router via
iBGP. It does not mean the entry belongs to "this AS".
A locally-generated route can be thought of as "belonging to this AS",
however, a router cannot assert that a locally-generated route "belongs
to this AS". It just asserts that the route was locally-generated within
the AS. Ownership of the route is data that needs to be gleaned from
other sources, e.g., RIR WHOIS data, speaking to the operator, e.t.c.
Whatever the case, a locally-generated route would not have an AS_PATH.
That is an easy way to tell for such a use-case.
> What I want to figure out is if this two ASes (the owner of the router
> and and the first one on the AS-PATH) connect at the location of the
> router, or if packets need to stay for some hops in the local AS.
>
So you want to determine whether traffic is hot- or cold-potato
forwarding from the point of view of your reference router?
Mark.
