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Re: the terms "priority" and "precedence"

2017-07-18 15:54:07
On 18/07/2017 23:54, Michael Richardson wrote:

We have many places in protocols where we want to express some ordering of
pieces of information.  We call these fields priority or precedence or

Just a side note: in the design of diffserv we paid a lot of attention
to that choice of words. You might care to read section 4.2.1 of RFC2474,
which could be summarised as precedence != priority. I think there is
quite some subtlety in this area, and not so much randomness in the choices.


sometimes other things.  Give encode things as numbers.

DNS's MX record has a "preference", in which lower numbers are better.
BGP has a LOCAL_PREF, in which higher numbers are better.
RAs have PreferenceLevel, in which higher numbers are better.
ROLL has "rank", in which lower numbers mean closer to the root.
OSPF has such numbers, which I forget at the moment.

Is there any consistent usage where preference is a term used when
higher numbers are better and priority when lower numbers are better?
Does the RFC-editor have any suggestions?  Or is it really all random.

]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
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Michael Richardson <mcr+IETF(_at_)sandelman(_dot_)ca>, Sandelman Software 
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