Subject: RE: The state of IPv6 multihoming development

From: "Michel Py" <[email-masked]>
Date: Thu, 24 Oct 2002 08:03:24 -0700

Shane,

>> J. Noel Chiappa wrote:
>> Two points. First, Craig Huegen seems to think that
>> any solution involving multiple addresses is infeasible
>> for a large organization. What's your reply to him?

> Shane Kerr wrote:
> Even if he's right, I think he's wrong to argue against
> end-point solutions based on multiple addresses. Given
> the current understanding of the problem and the approaches
> that have been outlined, doesn't it seem like wishful
> thinking to want One True Multihoming strategy? For small
> sites, binding multiple PA addresses into a single
> end-point seems like a straightforward, cheap, and
> effective solution.

Absolutely. It is clear that there is a place for both, and this WG has
been denying host-based solution in the misguided hunt for The Universal
Multihoming Solution. A PI solution is not the answer to everybody nor
is a host solution. My message to Peter Tattam and other people that
have designed host solutions is this: There is a place for what you are
doing, but also understand that it's not what everyone needs, and accept
the fact that your solution will have to coexist with something else.

> I'm not even 100% sure he's correct that multihoming
> needs to be in the network in order to do traffic
> engineering.  At least, I can envision end-site
> solutions that solve some (simple) classes of
> traffic engineering requirements.  :)

He is. It's not a matter of feasibility, but a matter of complexity.
Introducing transport-layer features would be the equivalent of NAT:
It's fine at home with your Linksys connected to a cable modem, but it's
a nightmare in the enterprise.

Michel.

---

From: "Michael H. Lambert" <[email-masked]>
Date: Thu, 24 Oct 2002 12:50:53 -0400

--On Thursday, 24 October 2002 08:03 -0700 Michel Py 
<[email-masked]> wrote:

[...]

> the fact that your solution will have to coexist with something else.

[...]

Is this a fair assessment?  There are three classes of multihomed leaf 
sites:

1) Entities, generally smaller ones, which can exist quite happily with 
multiple PA addresses (implying some degree of interchangeability among 
their providers),

2) Enterprises which require PI addresses either because they extend across 
multiple geographic areas (such as large corporations) or they connect to 
networks which are not interchangeable (such as universities with commodity 
and R&E connections) and

3) Regions which have the local topology to take advantage of 
geographically-based PI addresses.

It seems as though most discussion has tried to shoehorn both 2) and 3) 
into the same category.  I'm wondering if overall aggregation might be 
improved by giving these two classes separate PI space.

Michael

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