[Ntp] 16 bit extension numbers

Watson Ladd <watson@cloudflare.com> Thu, 20 February 2020 01:08 UTC

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From: Watson Ladd <watson@cloudflare.com>
Date: Wed, 19 Feb 2020 17:08:19 -0800
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Subject: [Ntp] 16 bit extension numbers
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Dear all,

The value of having all 16 bits available, and reserving 1/2 the space
(or maybe a bit less) as experimental is tremendous: it means we don't
have to worry about coordinating values and can let IANA assign them
from the bottom to the top of the space.

Grouping related extensions by having a code and a type as Harlan is
proposing wastes space: a type with no codes consumes 256 possible
extension values, and the greatest number of codes ever used is 10.
Each flag bit cuts the number of extensions in half: one has to be
really sure that bit is valuable, and they aren't: one of them is
depreciated and reserved for a protocol you shouldn't use.

I don't see any reason to be so profligate.

Sincerely,
Watson