1. Streaming Media Control n The protocol components of the streaming n RTP/RTCP n RVSP n Real-Time Streaming Protocol (RTSP)

2. Global multimedia data- and control architecture: n RSVP for reservation of the network resources n RTP/RTCP for transporting the real-time data and providing QoS feedback n RTSP for controlling the streaming media delivery n SIP for initiating the multimedia sessions n SAP for announcing the streaming media sessions by multicasting n SDP or SDF for describing the streaming media sessions n Further application level software The Protocol Components of the Streaming Media

3. Introduction to RTP/RTCP The Real-time Transport Protocol (RTP) works alongside with the Real-time Transport Control Protocol (RTCP). In fact, RTP as a protocol is made up of 2 parts - a data part (RTP) and a control part (RTCP). Together, these protocols deliver real-time traffic with timing information and feedback on the reception quality.

4. Real-time Transport Protocol (RTP) RTP is a transport protocol that meets the requirements of voice and other real-time data. RTP can transport data continuously rather than in bursts, and it can handle data delivery in multicast environments. RTP takes care of data that TCP cannot handle. Such data can include voice, video, etc. RTP was designed to run independently of the underlying transport and network layers of the OSI model.

5. Functionalities of RTP –Timing recovery –Synchronization –Content identification –Demultiplexing –Loss detection (error-recognition) –Security services

6. RTP Payload Stream Translation n Translator n Mixer

7. RTP Implementations Most implementations of RTP run in IP environments on top of the User Datagram Protocol (UDP). But RTP can also be used with other protocols such as the Asynchronous Transfer Mode (ATM), etc.

8. RTP in a Multimedia context

9. RTP in a Multimedia Context The RTCP packets report on the reception quality for a RTP session. The routers on the network communicate through RSVP (Resource ReSerVation Protocol) to set aside bandwidth for the transmission of the multimedia data. The RTP header provides timing information so that data delivery can be properly synchronized. The RTP header also specifies the payload type. In this way multiple data and data compression types are allowed.

10. Application of MPEG-H.261 Translator

11. Real-time Transport Control Protocol RTCP provides information on the quality of reception of the data transmitted This information is very useful to the applications as they can change the way they behave on basis of RTCP reports The RTCP feedback information can also be a useful tool for network managers

12. Traffic of RTP and RTCP Packages

13. More on RTCP RTCP is also used to keep track of the participants in a RTP session It does this by carrying the RTP source identifier, called the canonical name (CNAME), and the synchronization source identifier (SSRC). RTCP also controls the rate at which participants in a RTP session transmit RTCP packets The aim of this is to keep control traffic to a maximum of 5 percent of overall session traffic A RTCP BYE packet is transmitted for termination

14. Controlling RTCP Transmission Intervals, Bandwidth Fitting n The control traffic is limited to the maximum 5 % of the whole traffic by the modification of the RTCP package sending rate n The available bandwidth of the RTCP is allocated to senders and receivers, the part of the senders: all receivers together: n At sender: sending interval of RTCP packages: number of senders: bandwidth of the whole session: B average RTCP package size: n At receiver the sending interval RTCP packages: number of receivers:

15. Estimation of Packet Loss n The known expression for the TCP traffic can be used for the estimating the l packet loss ration of other traffic which uses the same path n Let c=1.22, RTT=200 ms, the encoding method is DVI (ADPCM version), 40 ms data packet, RTP/UDP/IP header 40 bytes, codec state 4 bytes, media data 160 bytes, thus p=204 bytes, sending rate 25 packet/s, thus the bandwidth required by the stream: n From these the packet loss ratio: l = 6.0 %

16. Conclusions RTP and RTCP work together Together, these protocols deliver real-time traffic with timing information and feedback on the reception quality

17. Real-Time Streaming Protocol (RTSP) n Product of the Progressive Networks and the Netscape Communications n Control protocol, one or more, for creating and controlling synchronized continuous media streams n Supports unicast and multicast n It can operate on the top of the RTP n Goals of the RTSP –Controlling data sending sessions in different applications, such as media-on-demand (MoD) –Rough synchronization of streams »The fine tuning is on RTP level by using RTP messages –Virtual presentations, which mean synchronized playing out from remote servers

18. Protocol Stack Including RTSP

19. RTSP Operation

20. The RTSP commands

21. Usage of the RTSP n The next addressing is for the whole presentation rtsp://turul.eet.bme.hu:554/gamefilm n An audio track inside a presentation: rtsp://turul.eet.bme.hu:554/gamefilm/audiotrack n The RTSP name-hierarchy is different from the URL name- hierarchy used by the HTTP

22. Example for building RTSP into HTML n This is a part of a web-side, which contains program-guide n The role of the RTSP is setting and controlling the delivery