[c-nsp] Same AS, different countries

[David Luyer]

To the second issue, there are a few things you can do:

1.	neighbor X.X.X.X allowas-in;
2.	set up IBGP sessions between the areas with next-hop
	rewriting (you may want to consider things like
	set ip next-hop OR update-source, NHS and static route);
	IBGP is intrinsically multihop anyway;
3.	set up a GRE tunnel between the areas and run an IGP
	(and/or IBGP) through the tunnel.

With point #3 it may even make sense to advertise in a restricted
(eg. no-export) manner some prefixes from multiple distinct
parts of the AS (if the GRE connected areas are actually connected
with good IP bandwidth and have good connectivity to some local
exchanges with peers with otherwise poor routes, for example).

However - you really shouldn't be splitting an AS if you don't
already know enough about BGP to realize the above.  It is not
something to be done without careful consideration.

David.

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of Lucas Iglesias
> Sent: Thursday, 16 December 2004 7:30 AM
> To: 'Kim Onnel'
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] Same AS, different countries
> 
> Hi Kim,
> 
> We do. We have 2 7206 in USA and a 7513 in Argentina, none of them
> directly
> connected.
> The only things are:
> - every prefix should be advertised only from one of them
> - no prefix advertised form one of them would be visible through BGP in
> the
> other routers (due to as-path loop preventing)
> 
> hope this helps.
> Lucas.-
> 
> 
> -----Mensaje original-----
> De: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net]En nombre de Kim Onnel
> Enviado el: Miércoles, 15 de Diciembre de 2004 05:06 p.m.
> Para: cisco-nsp at puck.nether.net
> Asunto: [c-nsp] Same AS, different countries
> 
> 
> Hello,
> 
> Can i maintain the same Autonomous System through different countries
> without having my devices directly connected ?
> 
> --
> ~Kim
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