[ppml] Policy Proposal: IPv4 Soft Landing

[Dan.Thorson at seagate.com]

> 1/8 is not usable for human reasons.  10/8 and 192.168/16 are not
> recoverable because that'd give people nothing left to NAT with, and NAT
is
> about to become even more prevalent than it already is as people
desperately
> try to avoid migrating to v6.  172.16/12 could probably be reduced to
> 172.16/16 without much grief, but pulling 172.16/16 would be tough
(though
> not as bad as 192.168/16).

Those of us in the corporate world use significant portions of the 172.16
/12, as well as 10/8 and 192.168/16.  RFC1918 needs to be sacred ground.

> 255/8 is tough to unreserve in practice for the same reasons as 0/8 and
> 127/8, so it's probably not 240/4 but rather 240-254/8.  If we're going
to
> do that, we might as well switch 225-238/8 to unicast too -- only 224/8
and
> 239/8 see much use in the (miniscule) multicast world, and the
exceedingly
> few oddballs using 225-238/8 could migrate to the remaining two /8s with
> minimal hassle.

There is danger in the assumption that there is a "(miniscule) multicast
world".  Whereas this is likely true on the Big-I Internet, multicast is
widely used in the corporate manufacturing world.  Who is prepared to pay
the price of lost connectivity when traditional multicast IP's are suddenly
deployed as end-user IP's?  Who will be modifying all my legacy system's IP
stacks?

I'm afraid I don't have much to offer in the way of solutions... I simply
call for caution when making assumptions of what is actually "used" re:
RFC1918 and multicast IP's.

danT

===================================================
Dan Thorson - Seagate Technology - CCIE 10754
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