Subject: GUSL / GUPI summary

From: "Michel Py" <[email-masked]>
Date: Wed, 4 Dec 2002 21:51:19 -0800

IPv6 folk,

I tried to summarize below the GUSL / GUPI deal.
We are pursuing two tracks here:

1. Uniqueness/limitation of site-locals: Two currents:

   1.1 Limit site-locals to disconnected sites.
       Margaret is preparing a draft.

   1.2 make site-locals unique (remove ambiguity).
       Also called GUSL. Two drafts to come:
       Bob and Michel+Charlie.

   Non-routability of site-locals could be guaranteed
   By the combination of default discards and of course
   by the local scope of such addresses.

   In *both* cases, SLs or GUSLs can *not* be routed
   outside the site, which means that for inter-site
   communications we need GUPIs.

2. Not-making-a-mess of GUPIs.

   GUPI = Globally unique, not globally routable.

   The first sad truth is that there is no consensual
   enforcement mechanism can guarantee that GUPIs will
   not end up being a global PI mess, IPv4-style.

   The second sad truth is that there is no consensus
   for un-aggregated PI today.

   The third sad truth is that there is no consensus
   either in giving away un-aggregated PI now and try
   to clean it later.

   The combination of the second and third sad truths
   is why we don't have IPv6 PI today.

   Therefore, GUPI candidates are indeed scalable
   (which very likely means aggregatable) global PI
   solutions. As a side note, this topic has been the
   quest for the Holy Grail of IPv6 multihomers since
   1995 for what I have references of.

Michel.

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From: Pekka Savola <[email-masked]>
Date: Thu, 5 Dec 2002 09:19:08 +0200 (EET)

>    communications we need GUPIs.

There is no technical reason I can see why inter-site communications
couldn't use GUSL's.

I would see the necessarity of working around default discards if you want
to interconnect two site-local domains as a feature, not a problem.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords

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From: Keith Moore <[email-masked]>
Date: Thu, 05 Dec 2002 02:33:05 -0500

There's no consensus enforcement mechanism that can guarantee 
anything else about IP operation either, but somehow it often 
seems to work.

There's no consensus for what to do with SLs either.
Getting consensus for what to do with SLs might require a consensus on GUPIs.

You seem to be saying that because we don't have consensus today on 
GUPIs that no reasonable solution exists.  I think we're still exploring 
the solution space.  

Keith

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From: Margaret Wasserman <[email-masked]>
Date: Thu, 05 Dec 2002 17:05:20 -0500

>We are pursuing two tracks here:

I am not sure that we have general agreement that there should be
two courses.  I, for one, do not think that we should create two
different types of addresses...

Margaret