[Standards] Whiteboard XEP, Gajim and GSoC2008
dave at cridland.net
Fri Mar 7 09:23:19 UTC 2008
On Fri Mar 7 03:58:37 2008, Joonas Govenius wrote:
>> On 3/3/08 6:23 PM, "Joonas Govenius" <joonas.govenius at gmail.com>
>> > What I don't like of the current SXE definition is the
>> inability of
>> > sending the whole document or chunks it, instead of being
>> obliged of
>> > sending all the necessary events for recreating the
>> If the extra bandwidth really is such a problem we could
>> define an
>> implicit way of creating the objects out of a chunk of XML as
>> mentioned but it doesn't seem worthwhile to me at this point.
> Boyd Fletcher wrote:
>> sending the entire document is a big show stopper for large group
>> collaboration (especially if you are using a large number of
>> whiteboard pages) and if your are using satellite/cellular
>> communications (like is very common in military or 3rd world
>> we dealt with the problem by using sequence numbers and the client
>> can request which numbers it wants to receive.
> You and Fabio are referring to slightly different issues here:
> 1. Fabio is concerned about the bandwidth used for sending the
> state to a client when it first joins the session. It would be
> higher by some significant constant factor so this is probably a
> legitimate concern but could be solved as I mentioned above; I just
> think it would be a little premature at this point.
Boyd's also mentioned this. Note that his design is used quite
heavily for presentation, where there's effectively an existing
"whiteboard" - a collection of SVG pages - unknown to the audience
prior to the event.
> 2. You are concerned about optimizing reconnects by taking
> advantage of the state that the client already has. I gave this
> some thought and there's actually no reason why SXE couldn't do
> basically the same thing as your protocol:
Of course, Boyd's mentioned this, too, as well as the related case
where a presentation using whiteboarding spans a day or two, and the
next morning, the presenter has updated the document.
This is a particular case of resynchronization, because the
assumption here is that there's a significant chunk of events that
may need shipping.
SXE appears, to my eyes anyway, to be particularly inefficient at
transmitting large changes, and I suspect that this may be at the
core of Boyd and Fabio's concerns.
Dave Cridland - mailto:dave at cridland.net - xmpp:dwd at jabber.org
Infotrope Polymer - ACAP, IMAP, ESMTP, and Lemonade
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