Transient content negotiation

I was in discussion yesterday with the developer of a system which provides
message redirection based on the current working location of the recipient
of a message.

For example, a person might be working in an office, from home or in a
distant hotel at different times.  Fax messages to that person can be
directed to a departmental fax machine in the office or to a dynamic Web
page to be viewed using a browser, depending upon the location of the
recipient at that time.

This suggests to me that it might be desirable to tag negotiable features
as 'transient' as a warning to intermediate systems to avoid caching these
(negotiable feature) values in an attempt to 'optimize' future
negotiations.  I see this as an extension of the idea by Joffe/Wing/Kline
of tagging negotiable features as 'authoritative'.

The idea of transient features might be particularly relevant if a
directory or other mechanism is used to cache previously offered
negotiation features to speed up negotiation in future communications.
This idea is probably more applicable to message passing in a
store-and-forward environment where the imperative is to avoid round-trip
delays.  But I believe that the distinction between 'online' messaging
(like HTTP) and s/f messaging is more one of degree than fundamental
difference, and mechanisms good for one may be applicable to the other.

GK.
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Graham Klyne
GK@ACM.ORG

Received on Wednesday, 18 June 1997 15:53:05 UTC