[c-nsp] BGP multihop between two sites

[Michael K. Smith - Adhost]

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Randy McAnally
Sent: Wednesday, September 02, 2009 1:51 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] BGP multihop between two sites

We have two sites advertising unique subnets via the same AS.  Since the
subnets originate from the same AS they apparently get dropped from the
tables
at each site.  

Each site has at least 3 upstreams taking full tables from each with a
6509.  

Site a has a single border router with dual supervisors.

Site b actually has dual border routers.  Each router handles different
upstreams and trades routes via iBGP.

So I think I need to set up a multihop session between the sites.  

Right now, traffic between sites is taking the floating default route
and
causes issues between sites when one of our BGP peers is down for
whatever reason.

What are the things to look out for when setting up this multihop?  Are
there
gotcha's to deal with given one site has dual active routers?

Can anyone provide me or point me to an example multihop config to work
from?

--
Randy

-----

You could also use the 'neighbor x.x.x.x allowas-in' which will let you
see your own AS being advertised incoming.

Regards,

Mike

--
Michael K. Smith - CISSP, GISP
Chief Technical Officer - Adhost Internet LLC mksmith at adhost.com
w: +1 (206) 404-9500 f: +1 (206) 404-9050
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