Subject: Re: The state of IPv6 multihoming development

From: Brian E Carpenter <[email-masked]>
Date: Fri, 01 Nov 2002 15:11:09 +0100

Iljitsch van Beijnum wrote:
> 
> On Wed, 30 Oct 2002, RJ Atkinson wrote:
> 
> > I think it is important to understand what the deployed reality is
> > today.
> > That impacts how widely useful some solutions might be, particularly
> > in the case of so-called "geographic addressing".  I also think it
> > is important to understand when a given solution will not work with
> > some/all deployed networks.  Financial realities mean that an IETF
> > document standardising a solution that requires more interconnection
> > probably will not lead to firms changing their topologies anytime soon
> > to meet such a requirement.
> 
> Nobody is proposing a solution that needs more exchanges in order to be
> useful. 

You may not think so, but I find it hard to believe.

> Just to be safe I've included a statement to this effect in the
> abstract of draft-van-beijnum-multi6-isp-int-aggr-00.txt. 

This statement will not impress business managers who see an
opportunity to create exchanges.

> New exchanges
> would only be necessary if this solution were to be used much longer
> than intended, 

I assume that whatever gets deployed will be around for 20 or 30 years
minimum.

> but as we approach one multihomer in 10 people even flat
> routing for a single city such as New York, Tokio or Mexico City will be
> problematic.

I wouldn't expect domestic users to be MH, so I don't expect to see
a million MH sites in those cities.
> 
> > > Granted the logical circuit topology is not limited
> > > to that, but again, how many real exceptions will exist, and how many
> > > of those will exist despite every attempt to prevent them?
> 
> > A fair number of exceptions exist today.
> 
> But then what's common today may be tomorrow's exception and the other
> way around. For instance, someone with ADSL doing BGP routing with IPv6
> and a "real" AS number is very rare today, while the number of
> organizations connecting to the internet in far apart locations is
> something that regularly happens (although I suspect the actual number
> isn't all that high). In the future, this will very likely be different.
> It could even be argued that existing cases are of no importance to
> routing scalability and it's enough to make new cases scalable.
> 
> Also note that as of today, NO end-user networks are multihomed in IPv6.

Just wait until we are running real production needing 99.9% up time.

  Brian

---

From: Iljitsch van Beijnum <[email-masked]>
Date: Fri, 1 Nov 2002 15:35:33 +0100 (CET)

> You may not think so, but I find it hard to believe.

What my geo proposal needs is many routers that interconnect with
routers from oether networks. Where they are located isn't important in
itself, but using geo at gives the _potential_ to have optimized
routing. Whether this potential is realized depends on the actual
topology. A different aggregation hierarchy doesn't provide the
potential for optimized routing by itself so it needs a level of
indirection to do this. This will scale better, but (unlike my geo
proposal) it can't be deployed in the very short term as it requires new
code.

> opportunity to create exchanges.

Which is a good thing irrespective of the solutions adopted.

> I assume that whatever gets deployed will be around for 20 or 30 years

There is considerable consensus here that a multi-address/locator scheme
will solve the long-term problem. This solution or set of solutions will
be around in 20 or 30 years. If my draft is implemented and not
superseded by something better in 20 years we obviously haven't been
able to agree on the requirements by then...

> a million MH sites in those cities.

1G was the lowest figure that wasn't challenged on this list as being
too optimistic. 1G = 1:10 in ~2050.

> Just wait until we are running real production needing 99.9% up time.

It's not the need that's lacking, but the means. The RIRs won't assign
you PI space, and the ISPs won't route it.