Re: Extending a /64

[David Farmer <[e-mail]>]

On Sun, Nov 15, 2020 at 2:56 PM Mark Smith <[e-mail]> wrote:

>
> On Mon, 16 Nov 2020, 07:19 Philip Homburg, <[e-mail]>
> wrote:
>
>> > Again, there are 35 trillion /48s in 2000::/3. How many would you
>> > need?
>>
>> It gets tight when you want the prefix to contain 39 bits to number around
>> half a million planes.
>>
>
> Why are half a million planes going to be on the Internet?
>

Being on the Internet is not the only justification for the use of globally
unique address space.

You mention that airplanes can fall out of the sky, it would be really bad
if an airplane every fell out of the sky, or collided with another
airplane, because of an address conflict. The proper used globally unique
registered address space makes such a conflict almost impossible. Where the
use of ULA makes such addressing conflicts statistically possible, even if
unlikely. With half a million aircraft and the potential consequences of an
address conflict, the ULA random selection algorithm is probably not a good
idea for this use case.

Whether or not the addresses used in the control systems of aircraft are
announced to the Internet, it seems completely justified to use globally
unique address space to address them. Further, a single very large
allocation something like a /16 or more to the international coordinating
body for the aircraft industry, allowing them to make sub-allocations to
aircraft operators, airport operators, navigational aid operators, etc...
seems like a quite reasonable address management scheme to me.

There are several ways to accomplish this; the IETF could make a special
allocation, a global policy could be coordinated through the RIRs and the
ICANN ASO, or the entity could approach one of the RIRs for an allocation
directly. As a past member of the ARIN AC, I know for a fact that ARIN IPv6
policy explicitly contemplates LIRs that are not necessarily connected to
the Internet, and contemplates generous initial allocations of up to a /16
for LIRs when justified. Further, ARIN uses a sparse allocation
methodology, reserving at least an additional nibble of address space for
future expansion.

Honestly, given the importance of the use case discussed, I don't see the
controversy, the allocation of a large address space allowing for the
assignment of /48s or /56s to aircraft and /48 or larger to airports seems
easily justified, and allocating it out of something other than 2000/3
seems quite reasonable as well, which would require IETF action. Further,
the use of IIDs other than /64 is completely unnecessary.

Thinking even more broadly it might not be a bad idea to allocate a whole
new /4 for transportation automation to cover aircraft, cars, trucks,
intelligent roadways, etc...

Thanks
-- 
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David Farmer               Email:[e-mail]
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota
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