Re: Distinguishing features and feature sets

At 12:56 03/02/99 -0500, Al Gilman wrote:
[...]
>The lazy client that doesn't want to dereference ACME-COMMUNICATOR will
>match it with ACME-COMMUNICATOR and treat ACME-COMMUNICATOR and SONY-GIZMO
>as values of different tags.  The industrious client will dereference
>ACME-COMMUNICATOR and know it matches SONY-GIZMO or the content of
SONY-GIZMO.
>Yes?
>
>I guess I just missed an earlier turn in the road -- like the motivation
>for hashes.

One motivation I see is that if SONY-GIZMO and ACME-COMMUNICATOR have the
same hash value, then they can be reasonably assumed to be the same feature
expression without actually knowing what that feature set is.

Another motivation is that if a recipient's characteristics change, the
change can be detected without sending the entire feature set.

An underlying motivation here is to save bandwidth whenever possible.  As
Ted pointed out, look what happened to HTTP Accept: headers because the
information to be communicated (repeatedly) became too voluminous.

#g


------------
Graham Klyne
([email protected])