Comparison of VBR and CBR service classes

It has been believed that a statistical multiplexing technique can bring an effective bandwidth usage. When it is applied to MPEG-2 video, it has been pointed out that two to several times multiplexing gain can be attained due to highly bursty nature of video traffic. However, most of past researches do not take into account the implementation aspects of this technique. In this paper, we thoroughly investigate the actual multiplexing gain by comparing ATM CBR and VBR service classes (deterministic and statistical service classes), and point out that the statistical multiplexing gain is far from one may expect.