nanog mailing list archives

Re: AS and advertisen questions


From: David Swafford <david () davidswafford com>
Date: Sat, 25 Jun 2011 22:11:26 -0400

Yep, we do it that way.

We basically treat each of our datacenter's as their own entity, using
separate space for each, but all with the same AS #.  What Joel
mentioned is going to be the major catch, in that for each of the two
disconnected AS's to accept the opposite sites routes, you'd need to
relax BGP's loop prevention check (which looks for it's own AS #
within the AS Path of incoming routes).

If your on Cisco gear, you'd need to add an additional command under
the BGP neighbor configuration that says "allowas-in".  Here's a breif
doc from Cisco on configuring this
http://www.cisco.com/image/gif/paws/112236/allowas-in-bgp-config-example.pdf

David.

On Sat, Jun 25, 2011 at 9:39 PM, Joel Jaeggli <joelja () bogus com> wrote:

On Jun 25, 2011, at 6:03 PM, Deric Kwok wrote:

Hi

Can we use same AS to advertise different networks in different location?

We would like to use Seattle as production network and New York as testing

eg:
Seattle: network 66.49.130.0/24

New York: network 67.55.129.0/24 and ipv6 network.

Thank you

Assuming you want the two instances to be able talk to each other you just have to relax loop detection so that you 
will accept prefixes from your AS...



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