Subject: RE: "unique enough" [RE: globally unique site local addresses]

From: "Christian Huitema" <[email-masked]>
Date: Wed, 4 Dec 2002 07:32:46 -0800

>          1) globally unique
>          2) provider independent (AKA "portable")
>          3) globally routable
>          4) indistinguishable from provider-allocated addresses by
>                  routers, applications, etc.

Margaret,

Routing solutions have to consider have to be considered with two
angles, politics and graph theory. The points you are making may be
great politics, but until the ghost of Dijkstra comes out with a
solution, graph theory still tells us that (2) and (3) are
contradictory.

-- Christian Huitema

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From: Keith Moore <[email-masked]>
Date: Wed, 04 Dec 2002 10:57:19 -0500

> but until the ghost of Dijkstra comes out with a

or until some other things change, e.g.
- ISPs are willing to route suboptimally (artifically make the graph simpler)
- we work out a way to compute routes on-the-fly (caching ones that have
  been recently used) rather than pre-computing the entire table
  (this probably implies that we push route computation to the edges
  and source-route through the core)
- we require certain interconnection paths (e.g. requiring major population
  centers to have a central peering point) in order to make the graph simpler

in other words, a substantial change to the routing architecture 
(heavy technical change) and/or enforced constraints on 
interconnection (heavy political change)

even if we solve the route computation problem, it's hard for me to imagine 
with forwarding tables containing ~ 2**48 prefixes.

Keith