08-06-2012, 05:10 PM
Real-time Transport Protocol
Real-time Transport Protocol.ppt (Size: 468.5 KB / Downloads: 0)
Outline of Talk
Multimedia applications’ requirements
RTP architecture
RTP details
Vic: an application using RTP
Summary: RTP does meet the requirements
RTP Architecture “ALF” and “ILP”
Application-level framing:
The application best knows its own needs
May not ask for retransmission, but for lower resolution
Integrated Layer Processing
Tightly coupled layers
Keeps data presentation from being the bottleneck
Gives the app. access to the data ASAP!
RTP: Summary
A very thin protocol
Usually built into application
No hard QoS guarantees
Designed for soft real-time apps
Depends on underlying network
Can run over ATM
Two components:
Media(data) transport: RTP
Control: RTCP
Mixers and Translators
Mixer
Could receive and combine various sources in an effort to reduce bandwidth
Translator
Keeps incoming sources separate
To transform to a lower quality format to broadcast on lower-speed networks
To send through firewalls
Summary
Multimedia applications have much different needs than http or ftp!
RTP meets those needs:
Minimized jitter
Synchronized sources
Dynamic, payload-specific frame length
Adaptation in the face of congestion
Interoperability
Effective use of bandwidth
Support for video-conferencing (multicast, IDs)
