[c-nsp] BGP Considerations isolated PoP

[Mark Tohill]

I know it does seem to be a popular thread, but just to clarify this.

The following is from nanog at merit.edu mailing list from way back. Does this sum my situation up?

"It's not necessary to mesh your BGP speakers - only a good idea. As long
as you don't care about sharing routing information (or even getting
decent routing), this will still work. I did it at my last ISP, and it
worked like a charm. 

I don't think he can possibly establish a full iBGP mesh without either
having direct connectivity or using tunnels. As long as he just meshes the
routers in the same site, and uses seperate address space at each site,
he's fine.!

Mark.


-----Original Message-----
From: Primoz Jeroncic [mailto:jp at softnet.si] 
Sent: 14 September 2005 21:11
To: Brian Turnbow
Cc: Mark Tohill; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] BGP Considerations isolated PoP

On Wed, 14 Sep 2005, Brian Turnbow wrote:

> If I understand correctly your third pop will not be connected to your existing 2 pops ?
> In that case you will need to set up IBGP via tunnels , it's not pretty but it'll work.
> Or divide your /16 so that the third pop announces part and the other 2 pops announce part and add static routes for connectivity between the POPs.
> Your AS will not get announced back to you from your upstreams in BGP.

It actually can be with "neighbor x.x.x. allowas-in". We have one part of our network
running like this with same AS but different upstream and no direct connection to
main part of our network. It's not nice, it's not as I would wish it would be, but it works.

>
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Mark Tohill
> Sent: mercoledì 14 settembre 2005 18.51
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] BGP Considerations isolated PoP
>
> Hi,
>
> We have our public AS announcing our /16 network over 2 PoP's to single
> upstream providers two adjacent PoP's. iBGP configured as it should be.
>
> What are the considerations if a third PoP were to be implemented, yet
> this would, for the time being, be essentially isolated from remainder
> of our network?

Have fun,
Primoz Jeroncic
Support - IP Connectivity & Routing
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