DocumentCode :
3495348
Title :
End-to-end delay of videoconferencing over packet switched networks
Author :
Baldi, Mario ; Ofek, Yoram
Author_Institution :
Dipt., Politecnico di Torino, Italy
Volume :
3
fYear :
1998
fDate :
29 Mar-2 Apr 1998
Firstpage :
1084
Abstract :
Videoconferencing is an important global application -it enables people around the globe to interact when they are far from one another. In order for the participants in a video-conference call to interact naturally, the end-to-end delay should be below human perception-about 100 ms. Since the global propagation delay can be about 100 ms, the actual end-to-end delay budget available to the system designer (excluding propagation delay) can be no more than 10 ms. We identify the components of the end-to-end delay in various configurations with the objective of understanding how it can be kept below the desired 10 ms bound. We analyze these components going step-by-step through six system configurations obtained by combining three generic network architectures with two video encoding schemes. We study the transmission of raw video and variable bit rate (VBR) MPEG video encoding over (i) circuit switching, (ii) synchronous packet switching, and (iii) asynchronous packet switching. In addition, we show that constant bit rate (CBR) MPEG encoding delivers unacceptable delay, which is on the order of the group of pictures (GOP) time interval. This study shows that having a global common time reference, together with time-driven priority (TDP) and VBR MPEG video encoding, provides adequate end-to-end delay, which is (i) below 10 ms, (ii) independent of the network instant load, and (iii) independent of the connection rate. The resulting end-to-end delay (excluding propagation delay) can be smaller than the video frame period, which is better than what can be obtained with circuit switching
Keywords :
circuit switching; code standards; delays; packet switching; telecommunication standards; teleconferencing; video coding; 10 ms; VBR MPEG video encoding; asynchronous packet switching; circuit switching; constant bit rate; end-to-end delay; global common time reference; global propagation delay; group of pictures; network architectures; packet switched networks; synchronous packet switching; system configurations; time-driven priority; variable bit rate; video encoding; video frame period; videoconferencing; Bit rate; Encoding; Humans; Packet switching; Propagation delay; Quality of service; Teleconferencing; Transform coding; Video compression; Videoconference;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
INFOCOM '98. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE
Conference_Location :
San Francisco, CA
ISSN :
0743-166X
Print_ISBN :
0-7803-4383-2
Type :
conf
DOI :
10.1109/INFCOM.1998.662918
Filename :
662918
Link To Document :
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