Dear Masataka,
my interest in this is national security. I see a problem with IPv6 in two
areas.
1. the 001 numbering plan as inadequate to national interests - digital
soverignty, e-territory organization, law enforcement, security and
safetey, etc. related reasons (I do not discuss their degree of relevance,
just the existance).
2. the Y2K syndrome. IPv6 has 6 potential numbering plan. Launching it in
real production without certifying it and the equipment to multiple plan
support capacity is unacceptable. When there will be millions on IPv6
inside without large scale testing of multiple numbering plan support, and
many ways of use, applciations etc. developed with one single actually used
plan in mind, no one will able to seriously propose an additional plan.
Comments welcome.
jfc
At 05:20 04/12/03, Masataka Ohta wrote:
Content-Transfer-Encoding: 7bit
Iljitsch;
We need to keep the size of the global routing table in check, which
means "wasting" a good deal of address space.
That's not untrue. However, as the size of the global routing table
is limited, we don't need so much number of bits for routing.
61 bits, allowing 4 layers of routing each with 32K entries, is
a lot more than enough.
Even in IPv4, where addresses are considered at least somewhat scarce, a
significant part of all possible addresses is lost because of this.
Only 20 bits or so for routing is, certainly, no good.
If we want to keep stateless autoconfig and be modestly future-proof we
need at least a little over 80 bits. 96 would have been a good number,
but I have no idea what the tradeoffs are in using a broken power of two.
If we assume at least 96 bits are necessary, IPv6 only wastes 2 x 32
bits = 8 bytes per packet, or about 0,5% of a maximum size packet. Not a
huge deal. And there's always header compression.
Stateless autoconfig is mostly useless feature applicable only
to hosts within a private IP network that 64 bits could have
worked.
128 bit is here to enable separation of 64 bit structured ID
and 64 bit locator.
Masataka Ohta