Re: An idea: GxSE

[Ben Black <ben@layer8.net>]

On Wed, Jun 20, 2001 at 05:27:18PM -0500, Jon (Taz) Mischo wrote:
> Border routers are often very heavily loaded.  Announcing valid GR/SK
> pairings via BGP or the like and then propagating them into an IGP
> (OSPF/IS-IS) would allow you to make translations further into the
> network, without renumbering.  Basically, you could make the network
> renumber itself.  If this is done properly, you could keep the
> intelligence at the edge, completely avoid renumbering, AND get better
> routing/multihoming performance overall.  This COULD be a win-win
> situation, I just think we have to look at it from all angles and proceed
> very carefully.
> 

The problem I ran into when thinking up something very similar to GxSE
was that _only_ the border routers know the actual prefix at the egress
point (barring end to end virtual circuits of some sort).  

My solution was to distribute "valid" prefixes in the IGP and have them
communicated to end hosts using an RIP-like mechanism to simply 
broadcast the set of prefixes hosts on a given segment might be
translated into (does that make sense?).  Hosts would then inform
remote ends of sessions (TCP, UDP, what have you), of the prefixes
from which they might communicate.  

Given the hop by hop nature of IP, I suspect it will be rather difficult
to have the translations occur anywhere but at the border.


Ben

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