What is the limit? (was RE: multi-homing fixes)

Wed Aug 29 23:41:17 UTC 2001

| If you had a router that could handle 2^32 prefixes, it will handle
| the IPv4 Internet.  Forever.  The whole growth curve argument is
| gone.

Sure, just about anybody can build a router which has 2**32 forwarding
directives burned into ROM.  It gets easier with fewer interfaces, too.
But, who wants a static network?

In the early 90s we had a network where you could wait a week
before the core of the Internet adapted to your topology change,
and changed its routing towards a particular prefix.  It wasn't
really much fun.

So, even though I convert (x/2)² into x/2 in what passes for my head,
I think that it's pretty clear that the problem isn't the state at
any given moment, but rather the rate of change of that state.

| The global routing table cannot grow exponentially forever.  

And neither can the rate of change.  The problem only has to be Too Hard
to compute affordably, not NP-complete.

(I bet others are already explaining this later in my $MAIL, but
I seem to be stuck on doing things linearly today...)

| For reference, there are approximately 10^80 electrons in the
| universe (per several physics sources I found on the net).  

Oh cool, particle physics.  How many degrees of freedom do these
electrons have?   Interesting point: a prefix in the global routing
table CAN have one or more moments of inertia.  Maybe something
multilevel is even better. Something like following the contributions
of constituent quark spin to a hadron or nucleon or would certainly
be even more appropriate, since indeed an IGP perturbation can lead to
fluctuation at the EGP (i.e. BGP) level, causing announcements to
rotate about a set of interfaces.  I bet Ahuja & Labowitz have even
recorded this happening.

Hey maybe there is some deep irony at work in that one can analogize
the work of Dyson Sr (QED, QCD) and Jr (ICANN) in this way...

| Not to minimze the short term issue, but to hand wave and say
| "it's exponential and we'll never get ahead of it" is crap.  It
| won't be forever, so let's get ahead of it.

There's lots of irony in that too.   Other than the hand-wave,
how do you propose to get (and stay) ahead of it?

	Sean.