[Standards] Whiteboard XEP, Gajim and GSoC2008
joonas.govenius at gmail.com
Fri Mar 7 03:58:37 UTC 2008
> On 3/3/08 6:23 PM, "Joonas Govenius" <joonas.govenius at gmail.com> wrote:
> > 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 document.
> 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 I've
> 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 countries).
> 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.
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:
The client that reconnects would send a "last-received-sender",
"last-received-id", and "last-sent-id" that identify the last <sxe/>
element that it received and the last <sxe/> element that it sent.
Assuming that that "last-sent" element came through, the joiner would
then only receive edits sent by others after the "last-received" element.
Only the server-side reflector (or bot) would be required to accommodate
these requests though because the clients aren't required to remember
details about who sent which edits.
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