SIP Conferencing Requirements Henning Schulzrinne Petri Koskelainen Columbia

SIP Conferencing Requirements Henning Schulzrinne Petri Koskelainen Columbia University SIP/SIPPING Interim Meeting 1

General philosophy § SIP philosophy: strictly separate media and session signaling – thus, media control (e. g. , retransmission requests) out of scope – thus, encoding profiles out of scope • orthogonal apply also to other conference types § Support central-controller conferences: – – central mixing or selection/replication or end-system mix possibly different addresses for different media sessions media session(s) identified by single SIP URI SSM: sources send to controller = root of multicast tree § Allow re-use of SIMPLE approaches – subscription permission conference join permission – buddy list pre-stored participant list SIP/SIPPING Interim Meeting 2

Don't invent new pieces (unless we have to) § Tease out conferencing-specific needs – modular, no H. 323 -like vertical stack § avoid conferencing-specific profiles § no T. 120 special case (except through gateways) § No need to define requirements for things that we already have: – – conference creation (but may need termination) conference joining and leaving participant muting renegotiation of leg codecs SIP/SIPPING Interim Meeting 3

No meta application § Believe that meta-app model is misguided seems to call for another signaling protocol, identifier, etc. – if no protocol or identifier, invisible – don't want uninstantiated relationships § we can set up sessions (including T. 120. . . ) via SIP/SIPPING Interim Meeting 4

General model § Divide into requests and notifications – requests = do something – notification = something happened § Requests may trigger notifications if action may be delayed or partial – human approval – group invite SIP/SIPPING Interim Meeting 5

Motherhood and Apple Pie § Simplicity § bandwidth-frugal (mobile) – incremental notifications and command – selectable notification granularity – templates for privileges SIP/SIPPING Interim Meeting 6

Components § Identified by object manipulated: – conferences conference management – participants within conferences user management – shared resource floor control SIP/SIPPING Interim Meeting 7

Conference management § Create conference [? ] § Delete conference – name vs. resources § Conference properties: – description (subject) – visibility to searching and directories – policies? SIP/SIPPING Interim Meeting 8

User management § § Cause server to invite user(s) Expel users List of pre-approved attendees User rights – invite, expel, approve others – manage & request floor – add media sessions § Join notification – with thresholding § Obtain list of members SIP/SIPPING Interim Meeting 9

Open issues § Separate conference name existence from resource allocation – want to keep name, but not mixing and bandwidth resources § Template management: – user lists – privilege levels ("chair", "secretary", "panelist", "audience") SIP/SIPPING Interim Meeting 10