[JDEV] Capabilities Discussion

[Stephen D. Williams]

Ideally, we would support both.  In fact, in the case of a lightweight client
it makes sense to use both at once: 

The lightweight client sends it's capabilities to be advertised by the
presence server so that it doesn't have to send 1000 copies of the info and

The lightweight client tells the presence server to only send essential
information and not 'extended presence' (or presence from categories beyond
'basic', for instance).

Sometimes it makes sense to broadcast status through a presence server and
sometimes it makes sense to respond to queries.  It probably makes sense for
queries to be to the other client and/or the presence server/directory also.

>From the perspective of a well-connected community of 'buddies', presence
makes more sense.  (You might want to know that your buddy has fired up
Quake.)  Avoiding polling was the basis for Buddylist/presence in the first
place.

Treating IM as an analog to the phone system, capability negotiation makes
sense.  (You can't be watching presence for everyone in the world just in case
you need to make a call to them.)


Disconnects on these topics are usually about how we perceive and weight our
models of usage, hence the impass at IETF IMPP.  If we can agree which models
are valid and when, we can come up with a clean plan to solve them all with as
little work as possible.  This applies to other things I'm going to be
bringing up: Solving the multimedia/file problem, security scenarios,
application middleware usage, protocol support for these features, etc.

sdw

Ryszard Sommefeldt wrote:
> 
> I'm still for making it part of jabber:iq:version.  A lightweight
> client on a limited bandwidth link should still be able to
> support a 100 user roster.  It has no need for the extra info
> sent out with a presence push.
> 
> Clients should do capability negotiation.  Old clients wont
> know to do this so they wont break.  New clients that
> know to do capability negotiation will negotiate features
> and work appropriately.
> 
> Having all that extra data in with the presence push just
> doesn't make good sense to me.  I'm coming at this from
> a lightweight client user's point of view.
> 
> I will be developing a PocketPC client next year and I
> don't like the thought of a Jabber server pushing way too
> much data my way, even though the client will support
> XHTML et al.
> 
> Ryszard
> 
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sdw
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