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

Mike Leber mleber at he.net
Tue Dec 21 19:39:21 UTC 1999


We've actually seen atleast two backbones do this.  Inconsistent
announcements at various exchanges gives it away.  They typically did this
sort of thing when they acquired several companies, renumbered the
acquisition's AS, and hadn't yet connected the parts.

On Fri, 10 Dec 1999, Jared Mauch wrote:
> 	It is possible to use a single ASN to do this, without
> meshing them.
> 	4) You can not have any bgp downstreams and have this work
> properly.

As long as the customer prefixes are announced from only one segment it
should work.

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

Also, any peer that is debugging routing problems might call about your
inconsistent route announcements.  Consistent route announcements are a
condition of many peering agreements. 

Mike.

> 
> 	- 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 at 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 at clipper.net>
> > Reply-To: list at inet-access.net
> > To: list at inet-access.net
> > Subject: Re: Portable IP space, isolated networks, BGP, etc...
> > 
> > On Thu, 9 Dec 1999, James Fischer wrote:
> > 
> > > From: "Troy Settle" <st at 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 at clipper.net 800.338.2629 x 402	         *
> > * Sufficient for today = Inadequate for tomorrow *
> > --------------------------------------------------
> > 
> > -
> > Send 'unsubscribe' in the body to 'list-request at inet-access.net' to leave.
> > Eat sushi frequently.   inet at inet-access.net is the human contact address.
> > 
> 
> -- 
> Jared Mauch  | pgp key available via finger from jared at puck.nether.net
> clue++;      | http://puck.nether.net/~jared/  My statements are only mine.
> END OF LINE  |
> 

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