The Differentiated Services (Diffserv) architecture specifies use
of the DS field in the IPv4 and IPv6 packet headers to carry one
of 64 distict differentiated services field codepoint (DSCP) values.
The codepoint space is divided into three pools for the purpose of
codepoint assignment and management: a pool of 32 codepoints (Pool 1)
to be assigned by Standards Action as defined in [RFC8126], a pool of
16 codepoints (Pool 2) to be reserved for experimental or Local Use
(EXP/LU) as defined in [RFC8126], and a pool of 16 codepoints (Pool 3)
which are initially available for experimental or local use, but
which should be preferentially utilized for standardized assignments
if Pool 1 is ever exhausted. Pool 3 codepoints are now utilized for
standardized assignments and are no longer available for experimental
or local use, as specified by [RFC8436]. The pools are defined in the
following table (where 'x' refers to either '0' or '1').
