[Standards] Proposed XMPP Extension: Stanza Repeaters
fippo at goodadvice.pages.de
Wed Mar 19 20:07:29 UTC 2008
Joe Hildebrand wrote:
> On Mar 18, 2008, at 4:25 PM, Pedro Melo wrote:
>> The repeaters concept doesn't solve the privacy list interactions either.
> Why not? For each list of folks that a server wants to send presence
> to, it creates a list. If that list has different people on it for
> different reasons, it creates different lists. In the case of presence,
> the server could, in the face of privacy lists being turned on, create a
> presence-out list and a presence-probe list for the user in question at
Typically, presence-out and presence-probe are identical. They are not
in the case of wannabe-invisible, where someone probes his contact, but
does not send presence to them. I love my servers mode for showing
probes and usually remove those people from my roster :-)
> each site where you have more than N users, where N should be determined
> through some sort of analysis at where the trade-off point is. I'm
> betting it's at least 10.
Mh... could be a problem if Peter still thinks that the average user
has no more than 10 users on his whole roster ;-)
I bet that you can lower the breakeven from 10 down to 3, if you
* have a well-known persistent list containing all legitimate
subscribers of your presence
* allow for (at least one) persistent lists composed of subsets
of the former (useful for permanent blocking)
* can start each list from the first list and subsequently remove people
> Yes, this could lead to **lots** of lists.
As long as all those lists are subsets of the (synced) roster...
creating lots of arbitrary lists sounds like a use-case for spamming.
> We better a) get the protocol right, b) make sure it's going to help,
> and c) implement it carefully.
Then let me add a tricky use-case for presence which does not
exist in muc and pubsub: the reply to a probe.
Even when you optimize the probes somehow:
Romeo ---> Montague Server ---> Capulet Server ---> Juliet (balcony)
Capulet Server ---> Juliet (chamber)
Capulet Server ---> Nurse
Capulet Server ---> Peter
Capulet Server ---> Sampson
Capulet Server ---> Gregory
Capulet Server (Anthony is offline)
Capulet Server (Potpan is offline)
there is a reply from the people who are online (sow the wind and reap
Romeo <--- Montague Server ---> Capulet Server <--- Juliet (balcony)
<--- <--- Capulet Server <--- Juliet (chamber)
<--- <--- Capulet Server <--- Nurse
<--- <--- Capulet Server <--- Peter
<--- <--- Capulet Server <--- Sampson
<--- <--- Capulet Server <--- Gregory
The number of stanzas is lower than the (non-optimized) 'probe storm',
but each stanza is bigger.
We've only been able to solve that by not probing at all.
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