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UCT-COE Seminar 000 Page 1 *


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UCT-COE Seminar 000 Page 1 *

  1. 1. Blending RTSP and SIP signaling for IPTV and VoD services in the IMS Presented by Robert Marston Department of Electrical Engineering University of Cape Town
  2. 2. Overview <ul><li>Introduction </li></ul><ul><li>SIP and RTSP in the IMS </li></ul><ul><li>SIP-RTSP Hybrid IPTV/VoD Architecture </li></ul><ul><li>Future Work </li></ul><ul><li>Questions </li></ul>
  3. 3. Introduction <ul><li>Internet Protocol Television (IPTV) and Video on Demand Services are expected to play a major role in NGN networks such as the IMS. </li></ul><ul><li>The Session Initiation Protocol (SIP) is used to transfer signaling information within the IMS core. </li></ul><ul><li>Currently there is no standard for handling of multimedia signaling in the IMS and current trends utilize the Real Time Streaming Protocol (RTSP) for the handling of the so called trick play functions (PLAY, PAUSE, FAST FORWARD, etc) </li></ul>
  4. 4. Difficulties of using RTSP with the IMS <ul><li>It is however difficult to incorporate RTSP into the IMS since RTSP was created to set up multimedia sessions and as such duplicates much of what SIP is already doing. </li></ul><ul><li>It is not easy to authenticate and bill clients for playing media due to the separate RTSP and SIP sessions being set up. </li></ul><ul><li>At the same time it is desirable to have separate control signaling for media streams which does not need to traverse the core IMS network. </li></ul>
  5. 5. Blending SIP, RTSP and HTTP <ul><li>A hybrid architecture that blends SIP and RTSP is needed. </li></ul><ul><li>In addition to this the Hyper Text Transfer Protocol (HTTP) is useful for transferring Electronic Program Guide (EPG) metadata to clients. </li></ul>
  6. 6. Hybrid SIP-RTSP-HTTP Architecture
  7. 7. The Electronic Program Guide <ul><li>Gives a listing of the broadcast channels and available video on demand content. </li></ul><ul><li>EPG Server is an HTTP server with access to a database containing channel and video information. </li></ul><ul><li>Client Interface merely consists of a web browser. </li></ul>
  8. 8. Content Guide Example
  9. 9. The IPTV/VoD Application Server <ul><li>Client invites the IPTV/VoD AS with the content URL he is requesting. Eg. </li></ul><ul><li>AS interfaces with the HSS to obtain user subscription data and determine whether or not the user is allowed to access the content. </li></ul><ul><li>If the client is allowed to watch the content he/she is requesting then the IPTV AS forwards the invite to the Media Control Function, else replies to the client with an appropriate response, eg. Payment required, not authorized to access, etc </li></ul>
  10. 10. The Media Functions <ul><li>Media Control Function (MCF) is responsible for setting up for the RTSP session with the Media Distribution Function. </li></ul><ul><li>Replies to the client with a SIP 200 OK and includes a SDP description of the media streams the client will be receiving. </li></ul><ul><li>Terminates the session after a period of time (e.g. 24 hrs) allowing the client unrestricted access to the content for this period. </li></ul><ul><li>In order to stay RFC 2326 compliant the MCF must act as a proxy and tunnel media streams to the client. It is then important that the MCF and MDF be co-located in order to ensure the delay cause by tunneling is minimal. </li></ul>
  11. 11. Future Work in this Area <ul><li>IPTV Service discovery functions. </li></ul><ul><li>IPTV Service management functions. </li></ul><ul><li>RTSP and SIP Hybrid is not ideal. Possibly implement a new standard that strips out the session setup of RTSP. </li></ul>
  12. 12. Questions?
  13. 13. Questions?
  14. 14. Questions?