Conferences and URIs. SIP Conferencing. Terminology and Model. SIP Conferencing. Participant

Transcription

1 SIP onferencing!! Motivators: n-way calling, video conferencing,!! Tightly coupled conferences!! ifferent conferencing models preserved!! Except for fully meshed conference: complexity just not worth it!!! Terminology!! Trying to avoid already overloaded terms as much as possible!! Set of protocols!! efinition of basic building blocks (SIP and other)!! Sample combinations to implement conferencing services!! Focus on basic SIP model!! dditional developments in XON currently in progress onferences and URIs!! onference types!! Basic: just plain SIP, no further means for control!! omplex: some conferencing features provided!! ascaded: several foci concatenated in a conference!! Sidebar: conference as (logical) part of another!! Focus Signaling center of a conference!! onference URI Identifies a focus (isfocus parameter may indicate this)!! Factory URI for automated conference creation!! Yields a dynamically generated conference URI in return 2010 Jörg Ott Jörg Ott 3 SIP onferencing Terminology and Model!! MUST work with basic SIP support only!! No awareness of conference!! Just a point-to-point call with minimal means for control!! Possibly augmented by out-of-band control (e.g. HTTP)!! Member types ()!! onference-unaware: plain-old SIP device!! onference-aware: supports conferencing features!! Focus: (one) center of a conference!! nonymous: Visible but unidentified participant!! Invisible: Participant whose presence is not known onference Policy ontrol Protocol PP Binary Floor ontrol Protocol BFP SIP ialog SIP Subscription Participant e.g. RTP Sessions Mixer onference Policy Floor ontrol Focus onference Notif. Service Mixer Member- Ship & Media Policy 2010 Jörg Ott Jörg Ott 4

2 Terminology and Model onference Bridge / MU () (RTP) Media Sessions onference Policy ontrol Protocol PP Binary Floor ontrol Protocol BFP SIP ialog SIP Subscription Participant e.g. RTP Sessions onference Policy Floor ontrol Focus onference Notif. Service Mixer Member- Ship & Media Policy + RTP udio + RTP udio + + RTP udio + RTP udio 2010 Jörg Ott Jörg Ott 7 SIP Signaling Relationships onferencing Scenarios (1) SIP / SP SIP / SP SIP / SP SIP / SP!! Simple conferencing scenarios!! Plain SIP only (RF 3261, 3264)!! Extend point-to-point call!! Works only with local focus; otherwise, new call required!! d-hoc conference!! utomated creation at focus!! IVR / TMF for control!! udio for information about the conference and its members (Eve)!! Reserved conference!! Same as ad-hoc!! Use external means for reservation and configuration (e.g. web) 2010 Jörg Ott Jörg Ott 8

3 onferencing Scenarios (2)!! dvanced conferencing scenarios:!! Support for all Transfer!! Support means to communicate information from focus to U!! Optional: means to manipulate conference and media policy!! Extend point-to-point call!! Join / create a conference based upon an existing dialog!! d-hoc conference!! Reserved conference!! Make use of additional conferencing features 2010 Jörg Ott 9 SIP Signaling Building Blocks!! Membership control!! Initiation of conferences: INVITE!! Inviting / adding to conferences: INVITE, REFER!! Leaving a conference: BYE!! Expelling from a conference: REFER (method="bye")!! onference control!! State change notifications: SUBSRIBE /!! ialog event package, conference event package,...!! onference / media policy control!! Might use XP data manipulation framework discussed in SIMPLE context!! Other!! etermine focus URI OPTIONS!! ugmented by other protocols!! Floor control: BFP!! onference control: XP? SOP? P? BFP-based??!! HTTP/HTML access to a web page for human interaction!! onference control, reservation, group management, etc Jörg Ott 11 Sample onferencing Features!! Invite participants (dial-in, dial-out), expel participants!! uthenticate new participants by members!! Obtain conference and media policy information!! Manipulate membership/conference policy!! Participant privileges, participant management (black list, white list)!! Floor control!! Explicit media control (media policy)!! onfigure media distribution!! dd / remove media sessions!! Floor control!! Manage access to conference resources!! Executed by floor control protocol, governed by floor control policy!! reate, control, and terminate sidebars!! Separate conference vs. media policy 2010 Jörg Ott 10 onferencing Event Package (1)!! Event package for notifying Us about conference state!! XML-based encoding of conference status!! Goes together with dialog state!! llows minimally enhanced s to learn about!! General conference information (focus URI, state, version)!! escription (display text, subject, free text, keywords)!! onference URIs (for participation and streaming)!! Service URIs (web page, conference recording, event subscription)!! Maximum user count!! vailable media (display text, type, status)!! Host information (display text, lifetime, web page, URIs)!! onference state (user count, active, locked)!! Users (entity == user URI, state)!! isplay text, ssociated ors, roles, languages, cascaded focus vs. endpoint!! Endpoint: further detailed status information!! Notification only: other mechanisms for conf. state manipulations 2010 Jörg Ott 12

4 onferencing Event Package (2) <conference-info version="1" state="partial" <users> <user state="full"> <display-text>arol</display-text> <endpoint <status>connected</status> <joining-method>dialed-out</joining-method> <media id="1"> <display-text>main udio</display-text> <type>audio</type> <src-id>583398</src-id> <status>sendrecv</status> </media> <media id="2"> <type>video</type> <src-id>345212</src-id> <status>sendrecv</status> </media> </endpoint> </user> </users> </conference-info> 2010 Jörg Ott 13 all Flow Example: User Joining lice Focus Bob arol INVITE sip:conf-id 180 Ringing ontact:conf-id K SUBSRIBE sip:conf-id 2010 Jörg Ott 15 all Flow Example: onference reation lice Focus Bob arol INVITE sip:conf-factory 180 Ringing ontact:conf-id K SUBSRIBE sip:conf-id all Flow Example: dding a User lice Focus Bob arol REFER sip:conf-id Refer-To: carol 202 ccepted INVITE ontact:conf-id 180 Ringing K SUBSRIBE sip:conf-id 2010 Jörg Ott Jörg Ott 16

5 all Flow Example: Removing a User lice Focus Bob arol REFER sip:conf-id Refer-To: carol?m=bye 202 ccepted BYE sip:carol Binary Floor ontrol Protocol (BFP)!! Support access control to floors aka. media sessions!! Session identification via SP attributes!! Shared or exclusive access (equivalent to read or write lock)!! Limited number of simultaneous floor holders!! lients (=participants) issue floor requests or release the floor!! Requests identify floor(s) concerned and may include hint message!! manages incoming requests and maintain floor state!! Queuing of requests possible!! Notifies clients about state changes (granting, revoking floor, floor holder)!! Governed by some conference policy rules (beyond BFP scope)!! Floor chair(s)!! Manage (grant, revoke, ) floors!! One or more chairs per floor one chair for all floors!! Protocol runs on top of TP or TLS!! Negotiated via SP offer/answer (connection-oriented media)!! Binary TLV encoding!! Request response protocol + asynchronous notifications!! Transaction identifiers for individual operations 2010 Jörg Ott Jörg Ott 19 all Flow Example: User Leaving lice Focus Bob arol BYE sip:conf-id BFP Overview Floor hair Terminate conference e.g. by non-sip means K Participant FloorRequest Notification Response: Granted or enied Floor ontrol ecision Notification The floor chair may also be co-located with the floor control server. The floor chair may be an automaton executing a predefined policy. Participant 2010 Jörg Ott Jörg Ott 20

6 BFP and SP!! BFP negotiation: another media stream!! etermine connection setup parameters and the floor control server!! Uses m=application (a=control is not a top-level MIME type)!! a=floorctrl:c-s (c-only, s-only)!! Media session identification for floor control!! Media level attributes for floor control!! Refer to SP label attribute at media level m=application TP/TLS/BFP * a=setup:passive a=connection:new a=fingerprint:sh-1 4::B9:B1:3F:82:18:3B:54:02:... a=floorctrl:s-only a=confid:4321 a=userid:1234 a=floorid:1 m-stream:10 a=floorid:2 m-stream:11 m=audio RTP/VP 0 a=label:10 m=video RTP/VP 31 a=label: Jörg Ott 21 Participant 1 Participant 2 FloorQuery Transaction I: 99 Bene I: 314 FloorStatus Transaction I: 99 User I: 314 FloorReqestInformation Beneficiary I: 1234 Status: granted BFP Example (2) Floor ontrol Floor hair 2010 Jörg Ott 23 Participant 1 BFP Example (1) Floor ontrol Participant 2 FloorRequest Transaction I: 4711 FloorRequestStatus Transaction I: 4711 FloorReqestInformation Transaction I: 4711 Status: pending, 1 st in queue FloorRequestStatus Transaction I: 0 FloorReqestInformation Transaction I: 4711 Floor hair Status: pending, 1 st in queue hairction FloorRequestStatus Transaction-I: 943, FloorReqestInformation FloorRequest I: 4711 Transaction I: 4711 Status: granted hairctionk... Status: granted 2010 Jörg Ott 22 onference Policy ontrol Protocol!! Needs to address different aspects!! ata model for conference and media policy, etc.!! Protocol for manipulating this data!! Minimal set of semantics-independent operations on a data structure or!! Semantic operations that are cause data manipulation (as a side effect)!! Several competing proposals!! onference State hange Protocol (SP)!! Realized as extensions to the Binary Floor ontrol Protocol (BFP)!! entralized onference ontrol Protocol ( 3P )!! XML-based protocol elements; may be carried over various transports (including SIP, SOP, )!! OMP: onference Object Manipulation Protocol!! Object manipulation based upon web services + SIP events!! MP: entralized onference Manipulation Protocol!! Object manipulation: draft-ietf-xcon-ccmp-11.txt!! XML-based data model: draft-ietf-xcon-common-data-model-21.txt!! onference event package extensions: draft-ietf-xcon-event-package-01.txt!! all flow examples: draft-ietf-xcon-examples-07.txt 2010 Jörg Ott 24

7 XON onferencing Framework (RF 5239)!! Builds upon the general SIP conferencing framework!! dds on functionality and policy!! ttempts to be independent of call signaling protocols!! llow bridging between multiple ones!! efines abstract operations on conference state manipulation!! ore elements (beyond the SIP framework)!! onference blueprint (template for conference creation)!! onference object (conference state representation at a given time)!! onference I (signaling-dependent) and conference object I (MP)!! onference policy (rights, permissions, limitations per role)!! Role (assigned to a user for authorization purposes)!! Media graph (media flow, including mixing, etc.)!! Sidebar (side discussion in a conference)!! Whisper (short-term one-to-one interaction) 2010 Jörg Ott 25 State of a onferencing Object!! onference description (time, duration, )!! onference object I for use by the conference control protocol!! Membership (roles, names)!! Signaling protocols (direction, call details, status)!! Signaling-specific conference Is!! onference user identifiers!! Floor information!! Sidebars, whispers,!! Mixer algorithms, inputs, outputs!! Implies media state!! (Floor) controls!! Represented in an XML-based data model 2010 Jörg Ott 27 Logical Elements of a onferencing System onf. control servers onf & Media control client onference object onference object onference objects Floor control servers Floor control client Foci MP BFP SIP SIP all signaling client Notification service Notification client MP Overview!! reation, modification, retrieval, and deletion of conferences!! Based upon HTTP as transport!! Plain and straightforward client-server operation!! onference control server is responsible for overall synchronization!! Relies on the POST operation (GET, HE optional)!! MIME type: application/ccm+xml!! Stateless operation!! Transactions are independent of one another!! Four basic operations!! reate, retrieve, update, delete!! Protocol transactions may comprise multiple protocol operations!! Individual transactions are atomic: all operations succeed or no changes!! XML for message and data encoding!! Request + response 2010 Jörg Ott Jörg Ott 28

8 MP Operations!! blueprintsrequest/blueprintsresponse!! confsrequest/confsresponse!! blueprintrequest/blueprintresponse!! confrequest/confresponse!! usersrequest/usersresponse!! userrequest/userresponse!! sidebarsbyvalrequest/sidebarsbyvalresponse!! sidebarsbyrefrequest/sidebarsbyrefresponse!! sidebarbyvalrequest/sidebarbyvalresponse!! sidebarbyrefrequest/sidebarbyrefresponse!! extendedrequest/extendedresponse!! optionsrequest/optionsresponse 2010 Jörg Ott 29 oncluding thoughts!! onferencing specs so far cover the minimal details for interactions between participants of a conference!! Which media streams to forward, how to mix, who can do what, etc.!! oes not contribute much to the user experience!! Only minimal support: e.g., by labeling media streams!! Telepresence to go beyond this (finally)!! reating a conferencing and interaction experience!! Taking into account position and direction of screen, room features, etc.!! Will need more semantic indications than additional complex signaling protocols 2010 Jörg Ott 31 Some esign iscussions!! Transport alternatives!! HTTP RU (create, retrieve, update, delete)!! reate: PUT!! Retrieve: GET!! Update: POST or PTH!! elete: ELETE!! SOP as an RP framework!! State manipulation design alternatives!! Semantic conferencing operation: define individual operations for every type of manipulation (add-user, add-media, etc.)!! Lots operations, complex to extend, but straightforward state maintenance!! Syntactic conference manipulation: define a data structure and read/write!! Few operations, easy to extend, but difficult to maintain consistent state (side effects)!! MP chose a hybrid approach 2010 Jörg Ott 30