[Standards-JIG] Re: MUC presence issues

Mridul Mridul.Muralidharan at Sun.COM
Wed Oct 11 15:06:32 UTC 2006


  Why should the server hold on to the last transmitted presence stanza ?
If I am not wrong , 5.1.3 and 5.11.4 of 3921 states that server should
send the directed presence to the receiving entity and also notify it in
case the sender went unavailable.
It does not say anything about using this directed presence for a probe
from the recipient subsequently.

So only state you might want on the server is the list of user to which
directed presence (not unavailable) was sent for the purpose of sending
an unavailable later on.

Or did I get the intention of these messages/spec wrong ?


Joe Hildebrand wrote:
> That means a lot more state for the server to maintain.  Instead of
> just holding the last transmitted presence stanza, it would have to
> hold the last transmitted presence stanza for each place you directed
> presence.
> I prefer the idea of auto-bouncing groupchat messages to unavailable
> resources.
> On Oct 7, 2006, at 7:51 PM, Ian Paterson wrote:
>> JD wrote:
>>> When [a server] receives an unavailable it has to broadcast it
>>> to all the places the user sent directed presence.
>>> The only time I really notice it is in the s2s case when a
>>> server goes down.
>> Yes, you're right.
>> AFAICT (please correct me again if I'm wrong), RFC 3921 and RFC
>> 3921bis do not provide for my server answering a presence probe that
>> was sent on behalf of another user who is not subscribing to my
>> presence, but who has received directed available presence from me.
>> Even so, I agree with you it would be a very good solution, with
>> general applicability for the reliability of directed presence... and
>> much better than the keep-alive alternative. :-) The request-response
>> would double the s2s traffic when compared to keep-alive, but there
>> would be no c2s traffic on either side... and clients would be kept
>> simple.
>> So perhaps this can be added to section 4.3 of RFC 3921bis? It seems
>> no presence leaks would occur as long as the user's server that sends
>> the probe receives an error if the user has already received
>> unavailable presence from me, and otherwise only receives an exact
>> copy of the last directed presence stanza that my server sent to the
>> user on my behalf.
>> - Ian

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