nanog mailing list archives

Re: AS and advertisen questions


From: Deric Kwok <deric.kwok2000 () gmail com>
Date: Mon, 27 Jun 2011 19:55:54 -0400

Hi all

Thank you so much for your help

I am not using cisco. From my understanding from your mail, I should
configure bgp as the following. Right?
What do I should pay attention also?


Seattle: network 66.49.130.0/24

announce out permit: 66.49.130.0/24
announce out deny 0.0.0.0
deny in 66.49.130.0/24
permit in any




New York: network 67.55.129.0/24 and ipv6 network.
announce out permit  67.55.129.0/24 and ipv6 network.
announce out deny 0.0.0.0
deny in 67.55.129.0/24 and ipv6 network
permit in any

Thank you again
On Sat, Jun 25, 2011 at 10:11 PM, David Swafford
<david () davidswafford com> wrote:
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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