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Re: Portable IP space, isolated networks, BGP, etc... (fwd)

  • From: Jared Mauch
  • Date: Fri Dec 10 07:23:55 1999

	It is possible to use a single ASN to do this, without
meshing them.

	Here's how:

	1) You can not run your bgp speakers in a default-free environment.

	2) You must point default at your upstream(s) in each location.

	3) Because you are using the same ASN, bgp will drop the
announcement from your other side once it sees it, to prevent
a 'routing loop'.

	4) You can not have any bgp downstreams and have this work
properly.

	5) This would be a higly fragile environment, and is not recommended,
but technically is possible.

	- Jared

On Thu, Dec 09, 1999 at 01:07:30PM -0800, Tim Wolfe wrote:
> 
> I'm forwarding this off inet-access because there is a lot more BGP clue
> here.  Anyone have any comments on the particular situation below, and/or
> regarding announcing different routes at multiple locations to multiple
> providers with single/many different ASNs?
> 
> Thanks,
> 
> -- Tim
> 
> --------------------------------------------------
> * Timothy M. Wolfe, Chief Network Engineer       *
> * ClipperNet Corporation / It's a wireless world *
> * tim@clipper.net 800.338.2629 x 402	         *
> * Sufficient for today = Inadequate for tomorrow *
> --------------------------------------------------
> 
> ---------- Forwarded message ----------
> Date: Thu, 9 Dec 1999 12:58:46 -0800 (PST)
> From: Tim Wolfe <tim@clipper.net>
> Reply-To: list@inet-access.net
> To: list@inet-access.net
> Subject: Re: Portable IP space, isolated networks, BGP, etc...
> 
> On Thu, 9 Dec 1999, James Fischer wrote:
> 
> > From: "Troy Settle" <st@i-plus.net>
> > Subject: Portable IP space, isolated networks, BGP, etc...
> > 
> > > I've been thrown into a situation where I've got 8 isolated networks
> > > connected to a variety of providers.  Eventually, most of these will be
> > > connected with our own backbone.  I need to find a way to make the
> > > transition as seemless as possible.
> > >
> > > First, it's my understanding that I can use a single ASN for the BGP
> > peering
> > > at each of these networks.  Am I mistaken?
> > 
> > Yes, this is a Big Mistake(tm).  One would need a unique ASN for each site,
> > but they are only numbers, and the cost is like $500 each.  Think about
> > the implications of two different sites, fed by the same provider, both
> > using the same ASN.   Not a pretty picture.  BGP hell.
> 
> Could you please clarify what exactly the problem with doing this is?  Many
> huge providers have multiple peering points that exchange routes using the
> same ASN for their peering routers don't they?
> 
> -- Tim
> 
> --------------------------------------------------
> * Timothy M. Wolfe, Chief Network Engineer       *
> * ClipperNet Corporation / It's a wireless world *
> * tim@clipper.net 800.338.2629 x 402	         *
> * Sufficient for today = Inadequate for tomorrow *
> --------------------------------------------------
> 
> -
> Send 'unsubscribe' in the body to 'list-request@inet-access.net' to leave.
> Eat sushi frequently.   inet@inet-access.net is the human contact address.
> 

-- 
Jared Mauch  | pgp key available via finger from jared@puck.nether.net
clue++;      | http://puck.nether.net/~jared/  My statements are only mine.
END OF LINE  |





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