Redploying most of 127/8 as unicast public

Fri Nov 19 15:39:03 UTC 2021

Owen DeLong wrote:
>
>> On Nov 17, 2021, at 21:33 , Joe Maimon <jmaimon at jmaimon.com> wrote:
>>
>>
>> And I think the basic contention is that the vast majority of 127/8 is not in use. Apples to oranges, indeed.
> This contention is provably false for some definitions of “in use”.

Determining the extent of this would be part of serious consideration.
>
> In what way would the LLA or ULA above be meaningfully different from 127/8 as deployed?

Because 127/8 is the exact same number on every system and it is routed 
the same way on every system and every system can choose to use it how 
it and it alone wishes to.

So this make it a deterministic prefix solely in control of the local 
system without any external context to ever be taken into consideration, 
by convention and standard.

LLA and ULA and whatever random prefix you may wish to use for loopback, 
whether in IPv6 or even IPv4 have none of these qualities.

>
>> Doesnt IPv6 deserve its own instead of squatting on IPv4?
> I don’t see any “squatting on IPv4” here.

It means that the only deterministic loopback prefix in IPv6 larger than 
a single address is the one IPv6 inherited from IPv4.
>
> Since, as you point out, use of the other addresses in 127.0.0.0/8 is not particularly widespread,

This is not my point, it is the contention of the draft standard and it 
is something I would hope is taken into serious consideration and 
researched properly/

My point is that to the extent this is true, the value of the space for 
other purposes could very well warrant re-purposing.
>   having a prefix
> dedicated to that purpose globally vs. allowing each site that cares to choose their own doesn’t seem like the best
> tradeoff.
>
> Owen
>
But this is how it is to be done in IPv6, so lets get some lack-of-feature parity going with IPv4.

Joe