[NNTP] 64-bit article counter extension strawman

[Andrew - Supernews]

>>>>> "Russ" == Russ Allbery <rra at stanford.edu> writes:

 Russ> I'd like Clive and, ideally, Andrew to weigh in, and would love
 Russ> to hear from other working group members as well, but that
 Russ> sounds good to me.  (Andrew's input would be very useful on
 Russ> this.)

I did some statistics on our active file (which has been running
without any number resets for a good many years) and current group
traffic levels.

If you assume unchecked exponential growth at a rate extrapolated from
past growth in each specific group, then we have maybe 10-20 groups
that are likely to run into problems within the 5 to 7 year timeframe
(none sooner). It's worth noting that if those assumptions hold, then
the feed volume at that time will be perhaps 48 TB/day, and the
busiest groups will be getting on the order of 10 million
articles/day, which has obvious implications for any scheme based on
resetting article numbers. (It also means that downloading the
overview alone for one such group will consume 4GB of transfer per
day, taking half an hour or so even at 20 megabits.)

It's obviously debatable how useful these assumptions are.

If you assume anything other than exponential growth, then the problem
is of course much further off (10 years or so even for the worst cases).

On the other hand, I would be quite astonished if there were more than
two clients in existence that allowed for 64-bit article numbers,
especially given that there are no servers generating such numbers.
Given the extent to which existing clients break at 2^31 or 2^32, it
is clearly unwise for servers to do so.

So there are several (non-independent) choices:

1) Leave the issue for now and work on it for Draft Standard. This is,
in my opinion, highly desirable.

2) Add language along these lines:
   -  clients SHOULD accept article numbers up to 2^63-1 (NOT 2^64-1)
   -  servers SHOULD NOT generate article numbers over 2^31-1
   -  servers MUST NOT generate article numbers over 2^63-1

3) Keep the 2^32 limit but add an extension for large numbers.

-- 
Andrew, Supernews
http://www.supernews.com