Subject: IPv16 has no version field...that is the point...

From: "Jim Fleming" <[email-masked]>
Date: Sat, 13 Mar 1999 12:55:43 -0600

I am not sure what resources you folks have access to
on the IPv4 Internet. I think an old IPv8 site is still around.
It was at http://ipv8.vrx.net, it is very out of date but at
least it shows how the 4 bit version field is handled.

Please do not be confused, there are only two of the
16 possible version values that the IETF actively supports.
Those values are:

0100 = 4 as in IPv4
0110 = 6 as in IPv6

There is still some question about whether IPv6 will ever
really be supported. It has taken so long to develop and
has become such a nightmare that it will likely go down
in history as the "PL/I of protocols".

Returning to IPv8 and IPv16...please note that IPv8 does
not continue to waste space, and bandwidth with idle bits.
[As an aside...if you want to see wasted bandwidth...look at IPv6]
IPv8 recognizes that a version bit pattern of 1XXX can
signal a router or processor that a version other than IPv4
and IPv6 is indicated. Since that 1 bit occupies the bit value
of 8 in a normal 4 bit version field, the name IPv8 is used.
[ People should note that when people like Tony Li mention
IPv8 they are not talking about some ancient assignment
that Jon Postel made which everyone can now ignore.]

As people have observed, a 4 bit field can not have a value
of 16, unless of course, one designated 0000 to be 16 which
is the next value after 1111 is incremented by 1. In some
systems, 1111 would be -1, so there is no reason why 0000
can not be viewed as 16, which would be 10000, if 5 bits
were available.

Since IPv16 has the luxury of only being used between systems
that know in advance that they are on the IPv16 network, then
there is no reason to waste bandwidth having a version field.
Therefore, IPv16 uses the entire 4 bit version field for addressing,
since IPv16 does not have to support the legacy options feature
from IPv4 and IPv8.

JF

JF