Subject: Multihoming in IPv6

From: Iljitsch van Beijnum <[email-masked]>
Date: Mon, 11 Nov 2002 22:49:12 +0100 (CET)

In IPv4, enterprises and other organizations can protect themselves from
ISP and telco outages by connecting to more than one ISP (multihoming).
This means the organization's IP address range must be visible in the
global routing table, which now holds approximately 115,000 routes.

The same thing could be done in IPv6, but it isn't, since this type of
multihoming isn't considered scalable enough. The multi6 working group
has been working on requirements for multihoming in IPv6 for a while
now, coming close to consensus on several occasions but never quite
reaching it.

Unfortunately, there is no multi6 meeting on the agenda for Atlanta.
That doesn't mean there is nothing to discuss. Solutions in the
following areas have been proposed:

1. geographical aggregation (draft-van-beijnum-multi6-isp-int-aggr-00.txt)
2. have boxes sit between the internal network and the border routers
   that map between provider independent, but not globally routable, and
   provider aggregatable address ranges (for instance,
   http://arneill-py.sacramento.ca.us/ipv6mh/draft-py-mhap-01a.txt)
3. extend mobility so entire sites can benefit from it
4. have multi-address aware transport protocols, such as SCTP
5. revisit/improve GSE/8+8
6. even more radical identifier/locator decoupling (hostnames as identifiers?)

As it looks like the long term solution will be some kind of
identifier/locator separation which will have a huge impact on all
aspects of IPv6, I think this topic deserves attention from a wider
audience than it's getting now.

(Since this will take a while to get off the ground, I think we need
something like my geo solution for immediate/short term relief, which
will scale one to two orders of magnitude, as well.)

Some of us will be getting into this deeper next week in Atlanta, and we
would be happy to provide an overview of what has been discussed on
multi6 (not just our own drafts/ideas) to anyone who's interested.
Contact me off-list for this.

Iljitsch van Beijnum

PS. Let me remind you in advance that this is NOT the forum to discuss
    the feasability of geographical aggregation or any of the other
    solutions mentioned. However, I'd be happy to discuss any and all of
    this off-list.

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From: "Perry E. Metzger" <[email-masked]>
Date: 11 Nov 2002 23:01:28 -0500

> audience than it's getting now.

Identifier/locator separation has been a topic of conversation at the
IETF for at least the last decade if not longer. In spite of this
continuous interest, an actual fruitful proposal has yet to arrive. I
highly recommend attempting to do a fully worked proposal complete
with documents before bringing up the topic in a broad audience -- it
will increase your credibility markedly.

Perry

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From: Keith Moore <[email-masked]>
Date: Tue, 12 Nov 2002 00:14:52 -0500

> I highly recommend attempting to do a fully worked proposal complete

the paradox is that it's difficult to know what requirements
a 'fully worked proposal' must meet without first talking to 
lots of people with different areas of concern.    a solution
which looks nice at layer 3 may look bad at layer 7, and vice versa. 

Keith

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From: Masataka Ohta <[email-masked]>
Date: Fri, 15 Nov 2002 03:03:13 +0859 ()

Perry;

> continuous interest, an actual fruitful proposal has yet to arrive.

A problem was that multi6 WG has been required to first produce
requirement document. It is just recently that so many people
recognize it not a productive approach.

> I

Meanwhile, I wrote an ID

	draft-ohta-e2e-multihoming-03.txt

on general architecture of scalable multihoming.

Then, we designed and implemented a solution based on LIN6 proposal.

Paper on it is available at:

	http://www.lab1.kuis.kyoto-u.ac.jp/~arifumi/paper/saint2003html/

							Masataka Ohta