Orit levin

1
Conferencing Requirements for SIP Based
Applications

• Orit levin
• orit_at_radvision.com

2

• draft-levin-sipping-conferencing-requirements-00.t
  xt
• Levin/Even/Zmolek/Petrie/Koskelainen
• RADVISION/Polycom/Avaya/Pingtel/Columbia
  University

3
The Outline of the Draft

• Hierarchal Application (Signaling) Model
• SIP Star Conferencing Application
• SIP Star Real Time Multimedia Conferencing
  Application

4
Reasons for Hierarchal Application Model

• A Means to Describe the Reality
• A Basis for Terminology Definition
• A Means to Understand Each Others Requirements
• A Means to Describe and Classify the Requirements

5
Meta Application Objectives

• Everything that is out of scope of standard
  applications
• Different Sets of Participants
• Everything that is out of scope of SIP
  Conferencing Application
• Bridging to PSTN End Users

6
Applications Reality
Example of a Complete Application
Chair Control Application in the Roadmap
Presence SIMPLE Based Application

• Members Management
• Applications Coordination

Real Time (Voice and Video) Star
Conferencing Application
Instant Messaging Full Mesh Application
White Board T.120 Based Application
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The Hierarchal Application ModelExample 2
Meta Application
SIP Voice Conferencing Application
White Board T.120 Based Application
Media Control
Voice (Data) Plane
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The Hierarchal Application ModelExample 2
Meta Application
SIP Voice Conferencing Application
White Board T.120 Based Application
Media Control
Voice (Data) Plane
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SIP Star Conferencing Application Model

• An Association of SIP User Agents for providing a
  shared application in Star Topology
• Center Participant vs. Edge Participants
• A Center Participant has a SIP Dialog with each
  one of Edge Participants and internally maintains
  correlation among the dialogs
• Both Center and Edge Participants are capable of
  being a Conference Chair

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SIP Star Conferencing Application
SIP Star Conference
EDGE
SIP Dialog
UA
CENTER
EDGE
UA
SIP Dialog
UA
SIP Dialog
UA
EDGE
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SIP Star Conferencing ApplicationMain
Requirements Guidelines

• Tight Conference Control (in contrast to loose)
• Pre-arranged and Spontaneous Conferencing Support
• Center Participant SHALL be able to add and
  disconnect SIP baseline Participants

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SIP Star RT MultimediaConferencing Application
Model

• SIP Star Conferencing Application with one or
  more RT Media (Data) Planes
• RT Media Plane is a subset of RTP media streams
  established by SDP means
• SHOULD contain Media Control Sub-application(s)
• May have Data Planes that are not RT Media Planes

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SIP Star Real Time Multimedia

Conferencing Application
SIP Star Conference
EDGE
SIP Dialog
UA
CENTER
RTP/RTCP
UA
EDGE
SIP Dialog
Media Processor
UA
RTP/RTCP
RTP/RTCP
SIP Dialog
UA
EDGE
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SIP Star RT MultimediaMedia Plane Model

• Media Plane groups RT media streams (belonging to
  different SIP dialogs) for various application
  reasons
• Media Plane contains zero or more Media
  Processors
• Media Processor contains zero or more
  Presentation Spaces

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Example a Default Audio Media Processor
Presentation Spaces
M
RTP
Audio Plane
AB
MC
MB
RTP
A
B
RTP
MAB
Conference participants Edge (Remote) A, B,
C Center (Local) M M, A, and B are the loudest
speakers Note Each remote participant has an
associated SIP dialog
Media Processor
RTP
C
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A TypicalSIP Star RT Multimedia Conference
Center Participant
Edge Participant
CONFERENCING/CALL PLANE
Conferencing Center Logic
Conferencing Edge Logic (Optional)
Basic UA
Basic UA
SIP
Conferencing Extensions
Presentation Spaces
VIDEO DATA PLANE
MP
RTP/RTCP
MP
RTP/RTCP
AUDIO DATA PLANE
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SIP Star RT MultimediaConferencing Application
Main Requirements

• Conferencing Presentation Requirements
• Identity of the user presented to you
• Presentation status (list) of your media
• Point-to-Point Requirements
• Capabilities
• Exchange Procedure
• Expressiveness
• Autonomous Media Control
• RTCP Feedback
• Application Driven Media Control
• Open Issue

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Issues We Need to Address First

• Hierarchal Application (Signaling) Model
• Do We Have a Clear Enough Terminology in order to
  Describe the Requirements?
• SIP Star Conferencing Application
• Conference Identification
• Scope of the Baseline Requirements
• Baseline Means for their Implementation
• SIP Star Real Time Multimedia Conferencing
  Application
• Direction for Resolving Application Driven Media
  Control Issue

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A Proposal Separate the Work into Three
DocumentsAllowing for Moving Forward
Simultaneously

• Hierarchal Application (Signaling) Model
• Definition and Examples
• SIP Star Conferencing Application
• Definition
• Requirements and their mapping to primitives
• SIP Star Real Time Multimedia Conferencing
  Application
• Definition
• Requirements and their mapping to primitives

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Backup Slides for Follow-up Discussion

• Conference Identification
• Application Driven Media Control

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Conference Identification

• User Wants to Create a Conference with Certain
  Specifications
• Conference Service Description is Required
• User Wants to Join an Existing (or a Scheduled)
  Conference
• Global Conference Identification is Required

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Implicitly The URI Option

• SIP URI Conventions for Media Servers
  draft-burger-sipping-msuri-01.txt
• The Request-URI of INVITE specifies a Conference
  (rather then a User)
• Registration with IANA
• Spontaneous Conference
• The Initiator of the Conference Creates a Unique
  Conference Identifier
• The New Conference Identifier Triggers Conference
  Creation by the MCU

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Explicitly New Headers

• The SIP Join and Fork Headers
  draft-mahy-sipping-join-and-fork-00.txt
• New Headers Used with INVITE to
• Explicitly Join a Dialog (specified by Call-ID)

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Application Driven Media Control

• Request for maximum (reserved) bandwidth
• Request for specific (current) bandwidth
• Request for using specific parameters
• CODEC and its Params, Resolution, Frame Rate,
  etc.
• A Showstopper Video Conferencing Applications
  MUST have deterministic way to switch between
  video sources