Correlation of multiple SIP dialogs. (draft-loreto-sipping-context-id-requirements-01.txt)

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Correlation of multiple SIP dialogs.(draft-loret
o-sipping-context-id-requirements-01.txt)

• Gonzalo Camarillo
• Salvatore Loreto
• 73th IETF, Minneapolis
• November 2008

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Motivation

• Generally, a given participant uses a single SIP
  dialog to
• establish a multimedia session.
• However, in some situations, several SIP dialogs
  are
• required to establish a single multimedia
  session.
• In order to treat the different media streams
  establish by
• the different SIP dialogs as part of a single
  media session,
• there is a need to
• logically correlate those dialogs.

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Distributed User Agent Clients

• Including an external UA in a conversation
• There are cases when folks may want to use
  different devices for a single session.
• The mechanism would be used to logically
  correlate an existing SIP dialog with a new SIP
  dialog.

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Use Cases 1/2

• 1 - Using Two Separate UAs to Start a
  Conversation
• Laura wants to establish a voice session with Bob
  using the desk phone as the microphone and the
  soft client as the speakers

• 2 Showing a Pre-recorded Video during a
  Conversation
• Bob is talking on his voice-only phone with
  Laura, who is on her multimedia phone.
• Bob wants to show Laura part of the TV show he
  recorded last night on his IP-TV device.

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Use Cases 2/2

• 3 Sending a File from a PC during a
  Conversation
• Bob wants to send a file to Laura from his PC
  during his conversation with Laura on his
  voice-only phone.

• 4 Including Remote Live Video in a Conversation
• Bob is talking on his voice-only phone with
  Laura, who is on her multimedia phone.
• During the conversation, Bob wants to show her
  (using the webcam-phone of the video-surveillance
  system) the new summer cottage he just bought.

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Requirements

• It MUST be possible to correlate an existing
  dialog(s) with a new dialog(s) as relating to the
  same media session.
• The state information associated to the
  correlation among a set of SIP dialogs must
  expire when the last of the SIP dialogs is
  terminated.
• UAs, that do not implement the correlation
  mechanism, should be able to handle the
  individual SIP dialog, that were supposed to be
  correlated, as well as possible.

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Existing Mechanism

• SIP Service Control RFC3087 propose to
  communicate context information using a
  distinctive Request URI. However, dialogs to be
  correlated do no necessary share the same Request
  URI.
• The Join header field RFC3911 allows inserting
  a new participant into a given conversation
  space. However, the Join operation is normally
  used to create or join a conference. Therefore
  the semantic for the correlation created by Join
  are different than the ones described in the
  requirements.

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Questions ?