Subject: Next question...

From: "Tony Li" <[email-masked]>
Date: Mon, 25 Nov 2002 11:43:14 -0800

Folks,

Have we reached consensus that we need to deal with multihoming
policies?  And do we agree that doing so at the per-host level
doesn't scale?

Thanks,
Tony

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From: Iljitsch van Beijnum <[email-masked]>
Date: Mon, 25 Nov 2002 22:32:12 +0100 (CET)

On Mon, 25 Nov 2002, Tony Li wrote:

> policies?

Not sure what you mean by that.

> And do we agree that doing so at the per-host level
> doesn't scale?

The problem isn't so much that it can't scale, but that it will be hard
to manage in large networks. If necessary, this can be fixed but this
makes the whole thing very complex. Complex gets you shouted at during
meetings.  :-(

My opinion: per-host multihoming is a good thing for two reasons:

1. Having two connections to the local network provides an additional
   level of protection against reachability problems, regardless of
   site multihoming
2. It will decrease demand for site multihoming so not-so-scalable
   solutions in this area have a longer life time

Another opinion: to achieve our scalability goals in a clean way, we
need another architecture for TCP/IP.

And a third: creating the above will take too long, so we need a
short-term routing based solution in the mean time.

:-)

Iljitsch

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From: "marcelo bagnulo" <[email-masked]>
Date: Mon, 25 Nov 2002 22:34:40 +0100

Hi Tony,

> Have we reached consensus that we need to deal with multihoming

I am sorry but i do not fully understand what do you mean by this.

That a site has to be able to define the exit router used for its packets?
That a site has to be able to set what ingress router will be used for the
response of the packets it sent before?
From an end-site point of view, something else?

From an ISP perspective, what considerations must be taken into account?

>  And do we agree that doing so at the per-host level

I would say that the management of such solution doesn´t scale, i mean when
a site has more and more hosts, it becomes harder and harder to manage
policies, i guess.
So i guess that this type of solutions is not suitable for big sites with a
large number of hosts, but it would work fine for small sites. I mean is not
that this type of solution does not scale when it is widely used, only that
it is not suitable for very large sites, where i guess it will not be
adopted. So i would say that we can work on this type of solutions, but
other solutions are needed to address large site multi-homing.

Besides i think that this type of solutions presents very good scalability
when considering other aspects, such as storing multiple locators of a host.
I mean, storing at each host its multiple locators scales better than
storing this information in the routing system or in specific databases.

Regards, marcelo