nanog mailing list archives

Re: distinguishing eBGP from show ip BGP


From: Mark Tinka <mark.tinka () seacom mu>
Date: Wed, 11 Mar 2015 21:30:46 +0200



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.


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