Re: An idea: GxSE

[Ben Black <ben@layer8.net>]

On Wed, Jun 27, 2001 at 02:16:42AM -0500, Jon (Taz) Mischo wrote:
> I understand your point, but with careful construction this shouldn't be
> an issue.  Assuming you use a link state protocol for the interior portion
> and you allow the border routers to notify the interior routers of the
> egress point, you could move the rewrite closer to the edge.  In fact, if

In order to do that, the interior routers carry full tables.  Whether the
information is distributed via BGP, an IGP (an unpleasant thought), or by
some mechanism specific to this purpose, the issue remains.

> you let the initial rewrite occur at the egress router, and then move the
> rewrite backwards into the network, with the egress router indicating
> validity of all recently used routes back into the IGP/other protocol for
> this purpose, you would know where the packets are going.
> 
> Basically, if there is a topology change, you just need to make sure
> your path is still valid.  Another behavior to control this may be to stop
> rewriting at the edge if you detect a topology change that may affect your
> internal routing, and let the egress router rewrite and re-alert you.
> 

I shudder to consider the troubleshooting implications of this.


Ben

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