Date: Mon, 12 Nov 2001 11:14:06 -0500
From: "J. Noel Chiappa"
<jnc(_at_)ginger(_dot_)lcs(_dot_)mit(_dot_)edu>
Message-ID:
<200111121614(_dot_)LAA25066(_at_)ginger(_dot_)lcs(_dot_)mit(_dot_)edu>
| I was merely pointing out that your catechismic canard about "no fully
| worked out example of separating location and identity" is ludicrous
| on its face, given the existence of an *IPv6* mechanism that does just that.
Aside from mobile IP being just as much v4 as it is v6, this is really
not a very realistic claim.
Mobile IP doesn't separate location and identity really - the location
of the home agent is an important part of the identity of the mobile node.
So, while the location and identity of the mobile node itself may have been
unlinked, the two concepts haven't been, so as a counter example, this is
useless.
It would truly have been nice if IPv6 could have done something to solve the
routing problems - but we don't have the answer to that yet. And we really
couldn't afford to wait for the answer.
There were two problems facing us 10 years ago - the exhaustion of the
address space, and (recognised a little later) the routing table growth.
The first of those is, unfortunately, a very hard limit - eventually there
will be absolutely no free addresses left at all. That one simply had to
be solved by a change of the protocols. No question about it at all. It
is also, a pretty trivial change to make. Notwithstanding that, 10 years
later, real deployment is just beginning.
On the other hand, the routing table growth doesn't necessarily need anything
new at all - maybe it will, once a solution is found. Maybe it won't.
Two things are clear however - first, had we waited until a solution was
found to design the next generation IP, we'd still be waiting (to start).
That is, deployment would be (at least) another 10 years away. And second,
routing table growth can certainly be handled by simply throwing large
amounts of money at the problem - perhaps prohibitively large, but it is
possible to keep functioning that way (we can build processors with gargantuan
address spaces, we can supply them with monstrous amounts of RAM, we can
install fibre with (close to if not) terrabit rates, to carry the info, and
we can parallelise the routing computations (at least for DV/PV protocols
like BGP) and throw lots of past processors at the problem. That's a pretty
brutal thing to contemplate, and would make the net much more expensive for
everyone - but at least there is no hard limit out there (note we have
already gone past the routing table sizes that people were claiming would be
too big to handle, back in the early days).
I certainly would have preferred a more radical next generation IP than
the one we're getting, but I certainly wouldn't want to still be waiting
for anything to have been done at all.
kre