On 10/21/10 11:21 PM, Iñaki Baz Castillo wrote:
2010/10/21 Daniel-Constantin Mierla<mico...@gmail.com>:
There are two aspects:
1) real time communication routing - voice, im, presence states
2) offline resource routing - vcard, predefined-content documents
1) can always have a correspondent in 2) while some things in 2) might not
be in 1).
Normally every user wants to do 1), but if the peer is offline, then server
can have the capability to re-route to corresponding resource in 2) (like
now with redirect to voicemail).
The things that are in 2) without a correspondent in 1) are on-demand
resources. Do I need to get a notification that you changed your vcard
immediately you do it? I would say no, I need to do it when I need to email,
send a snail mail, etc. which may happen when you are offline so the server
storage comes in the picture and sends it to me upon my request and your
authorization rules for that resource. That can be done very easy in the
reply body, without a need to create a dialog state in the server and send
notifies.
Interesting proposal. Let me some questions:
1)
- Alice has two active resources (alice-1and alice-2).
- alice-1 uploads a new vCard.
How is alice-2 notified about that change if there is no possibility
of subscription to the vcard?
Why it needs to be notified immediately? I haven't said that there is no
subscription, but for some cases are just kind of "stateless subscription".
Phone sends subscribe for a resource and gets the document in the reply
if allowed or a negative reply if not allowed. Timestamps can be used to
mark it has not be changed (like in http).
2)
IMHO avatar should be part of the vCard (as vCard already includes
photo and so):
- Alice is subscribed to Bob's presence (just presence).
- Alice retrieves the vCard (including avatar) of Bob. But there is no
subscription as you said.
- Bob uploads a new version of his vCard with a new photo.
How is Alice being notified about the change to display the new avatar?
Avatar and photo in vcard can be different, but anyhow, not the scope here.
In the light of useless traffic that can cost and not only that, would
it bring benefits that the avatar is updated in realtime by your
application even it is in standby and you don't want to communicate with
that user? Or the application is asking for updates when is some
activity related to that user? If there is no activity for a long time,
it can do a periodic refresh, anyhow many SIP mechanisms require
periodic actions.
3)
Where is the limit to say "this info requires subscription but this one not"?
All require subscriptions, but in many cases is no state associated
with, just one time pull of status/document. I haven't thought
thoroughly, but I hope the servers don't need to know subscription
states, only authorization rules, which are just stored documents and
should be generic, not a language related to presence, but authorization
for any kind of resources.
Cheers,
Daniel
--
Daniel-Constantin Mierla
http://www.asipto.com
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users@lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
