Re: draft-ietf-multi6-multihoming-requirements-06.txt

[Jay Ford <jay-ford@uiowa.edu>]

On Wed, 18 Jun 2003, J. Noel Chiappa wrote:
> First, I'm reminded of Churchill's famous line about democracy - about how it
> was the worst form of government, except for all the others. Similarly,
> having the edge-hosts make routing decisions seems like the worst place to do
> it - except for all the other choices!
>
> I don't understand why people get so worried about having the hosts be more
> involved in routing - but then perhaps my perspective helps me. E.g. way back
> when (i.e. the ARPANet), the network did congestion-avoidance, not the hosts,
> in part because "we have to protect the network and oh of course it's too
> complex for hosts to do". But having the network do it for the hosts turned
> out to have disadvantages. Now every host has very fancy congestion-avoidance
> algorithms in it, and it works fine, and everybody thinks its normal. Also,
> every human being (well, almost :-) is perfectly OK with the concept of
> hopping in their car/whatever and reading a map to get somewhere. It's not
> quantum mechanics, people.
>
>
> Second, you are right that (srcaddr,dstaddr) selection is something of a
> routing decision. However, making that choice more intelligently requires a
> far better routing architecture than the one we have now - one that is
> prepared to provide more information to hosts to allow them to make those
> choices. (See Figure 1.) Lacking that, flipping a virtual coin (perhaps a
> loaded one) is about as good as we're going to do...

Call me a control freak, but I (as campus network routing guy) would like to
get a little more determinism than is afforded by a virtual coin toss, even a
weighted one.  If the address selection must occur in the host, I at least
want a hook to influence the selection process (for srcaddr *and* dstaddr).

Also, what about the interaction between (srcaddr,dstaddr) selection &
anti-spoofing-type filtering?  The routers do the filtering, but the host
does the address selection.  How does that work?  I don't want to have more
spoofed attacks with IPv6 than we have now with IPv4.

________________________________________________________________________
Jay Ford, Network Engineering Group, Information Technology Services
University of Iowa, Iowa City, IA 52242
email: jay-ford@uiowa.edu, phone: 319-335-5555, fax: 319-335-2951