1 / 14

draft-allen-sipping-poc-p-answer-state-header

draft-allen-sipping-poc-p-answer-state-header. Andrew Allen: Research In Motion aallen@rim.com Tom Hallin: Motorola Jan Holm: Ericsson. P-Answer-State draft overview. The draft is split out from draft-allen-sipping-poc-pheaders-01, renamed and reset to -00 version

keitha
Download Presentation

draft-allen-sipping-poc-p-answer-state-header

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. draft-allen-sipping-poc-p-answer-state-header Andrew Allen: Research In Motion aallen@rim.com Tom Hallin: Motorola Jan Holm: Ericsson

  2. P-Answer-State draft overview • The draft is split out from draft-allen-sipping-poc-pheaders-01, renamed and reset to -00 version • Allows a PTT Server to indicate in a response whether the session is established end-to-end or only as far as an intermediate node (PTT Server) • Needed to enable media buffering prior to called party answer (early right to speak indication) • Needed to provide and indication to the caller that early right to speak buffering is taking place

  3. P-Answer-State Header • Values • Confirmed • Unconfirmed • May be included in Responses • 1xx (typical 183 Session Progress) • 200 OK • May be included in a sipfrag or included directly in a NOTIFY • NOTIFY sent as a result of the subscription established by REFER • Security Assumptions • Trusted PTT Server exists that has knowledge of currently selected Answer Mode of the terminating UA (PTT Client) • Trusted PTT Server that originating UA (PTT Client) trusts to accept and buffer media

  4. Changes(from draft-allen-sipping-poc-pheaders-01) • P-Alerting-Mode header definition has been removed • This extension is progressed separately as standards track (draft-willis-sip-answeralert) • Security considerations improved. • PUBLISH method has been added to usage table. • The procedures at the UA text has been split into UA-terminal and UA- intermediate-node for better clarity. • A session flow example section added. • Various nits and editorial corrections.

  5. PTT Server X PTT Server B UA B PTT Server A UA A Distributed Scenario (PES) Refer 200 OK INVITE INVITE Answer mode Authorization 183 Session Progress (P-Answer-State: Unconfirmed) INVITE NOTIFY (SIPFRAG 200 OK P-Answer-State: Unconfirmed) 200 OK (P-Answer-State: Unconfirmed) UA Auto Answers 200 OK Media Media Buffering 200 OK 200 OK (P-Answer-State: Confirmed) Media

  6. PTT Server AXB UA B UA A Consolidated Scenario (PES) Refer 200 OK Answer mode Authorization INVITE NOTIFY (P-Answer-State: Unconfirmed) UA Auto Answers 200 OK Media Media Buffering 200 OK Media

  7. Open Issues • Generalize to “contains an answer” instead of “contains a SDP answer” • Accepted • Delivering P-Answer-State header to originating UA in Consolidated Pre-established Session (PES) scenario • Problem when there is no response containing P-Answer-State header to include in the sipfrag • Include as a header of the initial NOTIFY? • Include as a header in a “dummy” 100 TRYING sipfrag in the initial NOTIFY? • Include in the 2xx response to the REFER? • Something else? • What to call the “Intermediate Node” (B2BUA or Proxy) • PTT Server? • PoC-Intermediate? • How much to say or define about the general “Intermediate Node” behavior in the draft

  8. Questions

  9. Backup Slides

  10. PoC Session Concepts • On-Demand Session • Conventional end-to-end INVITE initiated PoC session establishment at Push-to-Talk time • Pre-established Session • Pre-established codec negotiation between PoC Client and Participating PoC Function using INVITE prior to Push-to-Talk time • Semi-permanent Pre-established INVITE dialogue with Participating PoC Function maintained • Refer within the INVITE dialogue used to initiate POC session establishment at Push-to-Talk time

  11. PoC Concepts and Challenges • PoC (Push to Talk over Cellular) Concepts • Sessions established using Push To Talk button • Right to Speak Indication (e.g Audible tone) • Half Duplex media • Talk Burst Control • 1-1 and Group Calls • Manual and Auto-Answering terminal • Manual Answer Override (MAO) for dispatch • PoC Session establishment latency challenge • Highly bandwidth constrained cellular networks • Push-to-talk to Right-to-speak indication latency requirement in order of a second

  12. OMA PoC Architecture

  13. PoC Server Functions • Participating PoC Function • Provides policy enforcement for incoming PoC Session (e.g. Access Control, Incoming PoC Session Barring, availability status, etc) • Stores the current Answer Mode, Incoming PoC Session Barring and Incoming Instant Personal Barring preferences of the PoC Client. • Controlling PoC Function • Acts as the Focus for the PoC Session • May act as an exploder • Provides the centralized media distribution • Provides the centralized Talk Burst Control functionality

  14. PTT Server X PTT Server B UA B PTT Server A UA A On-Demand Scenario INVITE INVITE INVITE Answer mode Authorization 183 Session Progress (P-Answer-State: Unconfirmed) INVITE 200 OK (P-Answer-State: Unconfirmed) 200 OK (P-Answer-State: Unconfirmed) PoC Client Auto Answers Media Media Buffering 200 OK 200 OK (P-Answer-State: Confirmed) Media

More Related