MPEG-2 Traffic Shaping for Real Time Video Services on ATM Network-“Intra Slice Coding

ATM(asynchronous transfer mode, the transfer mode of B-ISDN(broadband-integrated service digital networks) is so flexible to support various kinds of traffic classes including VBR(variable bit rate) traffic. VBR traffic class is useful for delay-sensitive application such as video phone and teleconferencing. Video bit stream encoded by MPEG-2(moving picture experts group) encoder is variable in bit rate if it is not buffered. Most network other than ATM network require constant bit rate. It caused delay and jitter or channel waste to transport traffic with variation in bit-rate through a CBR(constant bit rate) channel. Even for ATM, it is desirable to reduce such variation. This paper shows that the proposed traffic shaping algorithm using the intra slice coding mode in MPEG-2 can be useful to smooth variation in MPEG-w video traffic without inducing any buffering delay, and jitter. The less is variation in bit rate of a session, the less communication resources are allocated to the session. For quantitative analysis of this effect, GCRA(generic cellrate algorithm) is used, GCA is an algorithm popular for an ATM switch to police users.