In message
<C99A689B0CB9D111AF3F0000F8062CCD0BC66355(_at_)zkoexc2(_dot_)zko(_dot_)dec(_dot_)com>,
"Cor
zine, Gordie" writes:
Using the IP address, you index into a table with 100 M entries, pick up an
index into the 75K entry routing table. You now have two tables that
require maintenance, that's all. If customer changes ISP, their entry in
the first table is changed. Link is down, the second table's mechanisms
handle it. Use a 64 bit processor architecture, memory is cheap.
Re-architecting the Internet is going to become all but impossible.
The issue isn't table lookup; it's the routing table calculation (and, in
the case of your particular example, the sheer amount of data that has
to be passed around). Put another way, how does each router know what
should be in those 100M entries?
Its a matter of separating routing from identification.
Phrased somewhat differently, there are a lot of people who agree,
though it's still a controversial notion. See if you can find a copy
of draft-ietf-ipngwg-esd-analysis-06.txt (or -05) -- it's a description
of the best worked-out proposal, plus a refutation of it. (I disagree
with the refutation, but I'm not going to go into that now -- I think
that the proposal is sound.) Briefly, the idea is to use the
high-order 8 bytes of the v6 address for inter-site routing, and the
low-order 8 bytes for host id.)
But that still requires hierarchical assignment and routing for the
high-order 8 bytes. *No one* knows how to do it any differently.
Look, my days as an engineer are a distant memory, so I won't try to work
this out in detail.
Mere assertions that it is possible, in the face of the prevailing
wisdom that it isn't, just won't cut it. Maybe you're right, maybe it
can be done -- and if so, it won't be the first time that the accepted
wisdom is wrong. But the
Maybe there are irrefutable reasons why this can't be
done, but I do believe the current architecture will lead to premature
exhaustion of the address space.
Apart from the fact that 128 bits is Really Big, v6 is supposed to have
easy renumbering, so that we can renumber sites as they're move around
to different pieces of the topology.
--Steve Bellovin