Re: On the use of multiple PA prefixes or a single PI prefix for IPv6 multihoming

[jnc@mercury.lcs.mit.edu (Noel Chiappa)]

    > From: Iljitsch van Beijnum <iljitsch@muada.com>

    > I wasn't aware that I'm so set in my ways that people can predict
    > whether I'll like something in advance...

It's not just you, almost *nobody* likes it! So I'm merely going with the
odds! :-) Although I admit you seem to not be afraid of offbeat ideas, so you
may well like it at a purely technical level. Although I predict you will be
daunted by the magnitude of the change... :-)


    > So let's hear it, I'm interested to know if you're right. (-:

Well, basically, I think we need to move the "path selection" function
out of the "network" (i.e. the routers), and let the hosts (or, if they
are lazy/stupid, an agent acting on their behalf) do it. To do this, they
obviously need more information, which I claim should be maps of network
topology.

I have two standards points to make to people who roll their eyes at this
hopeless technological naivete, and say that it's "obviously" way too
complex a job to give to the hosts:

- Back in the 1970's, the "network" took care of flow/congestion control and
also reliability, and now hosts do all this - using some fairly complex
algorithms that took us decades to get working well. And having made that
fundamental architectural reorganization, it's now "obvious" to everyone that
that's the way it ought to be.

- This is the way we do cars and highways, and it seems to work just fine.


Anyway, making this (admittedly major) architectural change kills about
17 dozen birds, of which the "how do I pick the best address for the
destination" is one.

And yes, I know this is a really, really, *really*, ***REALLY*** big
change. But, surprisingly, when you start working through the details,
there are ways to incrementally deploy it, ways which don't mandate
changes to all hosts before it can begin to be useful.

	Noel