Constant Bandwidth Transmission in continuous and non-continuous modality

Multimedia applications require special Quality of Services (QoS) from the networks in terms of throughput, delay and delay jitter. The traffic generated from this kind of applications is mostly of VER type. For VER data flows it is very difficult to evaluate the network resources necessary to guarantee the required QoS and, at the same time, to optimise the network utilisation. The Constant Bandwidth Transmission (CBWT) mode (Lodato, Lopes 1998) performs traffic transformation with the aim of obtaining a traffic source that is easier to model and to manage. In this way the resource allocation schemes, as well as the CAC and Policing procedures, are greatly simplified. Depending how the CBWT traffic shaper is fed, the resulting transmission can be continuous or noncontinuous. The first case has been already discussed, from a qualitative point of view, in a previous paper (Lodato, Lopes 1999). In this paper a new CBWT modality, called non-continuous, is described. Numerical results of some simulations, carried out using MPEG compressed video, are reported and a comparison of the two modalities is presented.