[Standards-JIG] Trying to understand

Matthias Wimmer m at tthias.eu
Thu May 18 17:36:11 UTC 2006


I am trying to understand the different sides of the "smart presence 
distribution" discussion. I see two wings in this discussion.

The one that support the proposed protocol: Their main concern is about 
reducing the number of stanzas, that are transmitted. They are willing 
to make it in a way, that extend XMPP nicely and the syntax that is 
used, is not their concern.

The other: Their main concern is about privacy and which side does the 
decission on how gets the presence information. (They concern is NOT 
that each stanza has to be transmitted several times, just that they 
want control on who get the stanza.)

Am I right this far?

JEP-0033 has already be mentioned several times, and I have not seen 
anybody yet, being against this JEP. Right? So let me propose that 
JEP-0033 style of addressing presence stanzas could be a compromise. We 
will keep the originating server responsible for deciding who gets the 
presence AND we will only have to transmit the stanza once to the 
destination server.

Let me make an example: We have a <presence 
from='user at example.com'><show>xa</show><status>out for a 
while</status><priority>0</priority></presence> which has to be sent to 
different users at "jabber.org". So we only have to send this stanza 
once to "jabber.org" the following way:

<presence from='user at example.com' to='jabber.org/jep0033'><addresses 
xmlns='http://jabber.org/protocol/address'><address type='to' 
jid='stpeter at jabber.org'/><address type='to' 
jid='jer at jabber.org'/><address type='to' 
jid='temas at jabber.org'/></addresses><show>xa</show><status>out for a 

Whouldn't that be okay for all of us? I think at least we should all be 
able to accept this protocol.

One additional note: Letting the originating server include who gets the 
presence (either distributing presence as now or using JEP-0033 for it) 
is already the protocol to syncronize rosters we are searching for! The 
destination server just has to do the following:
- if presence arrives but there is no such user, or the user is not 
subscribed to this presence: send back an unsubscribe
- if presence probe arrives but there is no such user, or the user is 
not authorized to see this presence: send back an unsubscribed
This is already enough to keep the subscription states at the rosters in 

Tot kijk

Matthias Wimmer      Fon +49-700 77 00 77 70
Züricher Str. 243    Fax +49-89 95 89 91 56
81476 München        http://matthias.wimmer.name/

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