[Standards] shared XML editing update

Boyd Fletcher boyd.fletcher at je.jfcom.mil
Mon Feb 4 23:09:47 UTC 2008




On 2/4/08 5:19 PM, "Peter Saint-Andre" <stpeter at stpeter.im> wrote:

> Joonas Govenius wrote:
>> Boyd Fletcher wrote:
>>> we still do not believe that SXE is appropriate for whiteboarding
>>> especially
>>> when scaled to hundreds of concurrent users in a single session.
>>>   
>> I actually think SXE would scale to many users very well because:
>> 
>> a) it makes no difference for an individual client who the edits come
>> from or how many users there are in the session
>> 
>> b) the server (if one is used) doesn't do any processing of the edits;
>> it merely forwards them to the participants.
>> 
>> c) SXE causes minimal "locking" of the document; only simultaneous edits
>> to the same DOM node conflict.
> 
> That seems reasonable to me.

but without a server process collisions are going to happen and resolving
them could be tricky. the whole weighting approach seems to risky. It relies
on the good behavior of the client way too much.

also getting current state is extremely expensive and unreliable.  it relies
on another client to send it to you instead of a more reliable server.

> 
>> On the other hand, SXE doesn't currently specify any access control to
>> limit who can edit the document. That may be a problem for the kind of
>> large sessions that you're thinking of.
> 
> IMHO a large session would be done in a MUC room or via a specialized
> component, and that's the level at which floor control would happen.
> 

that is kinda how we do it now. we get the access control list from the
associated MUC room but we don't send the whiteboarding content over the
MUC. It goes to a separate component on the server.

>> Also, as Fabio Forno pointed out, SXE may be problematic with a high
>> volume of edits but, in the case of whiteboarding at least, the volume
>> would probably not increase very much with the number of participants
>> because most participant would merely "watch".
> 
> I think that would be the case for the vast majority of large editing
> sessions.

I know of lot of large enterprise collaboration customers that would
disagree. Any either case, why do we want to push out an approach that has
such a large potential problem. not to mention the ones described above and
other emails.

> 
> Peter




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