In this paper the impact of the usage parameters control (UPC) parameters on a dynamic bandwidth allocation scheme is investigated for the transmission of MPEG video traffic. This is a analyzed assuming a self-conformance check by the source so as to avoid the transmission of non-conformant traffic that risks being discarded. This control is integrated within the implementation of a periodic allocation protocol which allows simultaneous coding (in the source) and reservation (in the network). The results of MPEG-1 traces show that for higher loading conditions the UPC parameters interfere with the allocation scheme in a way that degrades the performance. Further, an over-average degradation of more important traffic (belonging to I frames) can be eliminated by applying internal selective discarding.

A periodic allocation protocol, called anticipated traffic allocation protocol (ATAP) for real time VBR traffic is proposed. The main objective of this protocol is to dynamically allocate the available bandwidth to real-time VBR sources, i.e. to be more efficient than the CBR allocation and at the same time more secure that the "walk-in" allocation. The ATAP unit is located at the network entry node between the real-time encoder and the applied bandwidth allocation protocol in the network, the fast reservation protocol FRP/DT. This reservation protocol cannot satisfy the real-time requirements, since the source would have to wait at least a round trip delay to reserve a required bandwidth increase. Hence, the ATAP proposes to anticipate and allocate the bandwidth one period in advance. This permits the encoder to adjust its coding bit rate according to the network loading condition. Doing so, a congestion will gracefully degrade the subjective quality of the signal, instead of "blindly" loosing cells at the network entry node. A minimum bit rate negotiated at the connection set-up is always guaranteed to assure the connection continuity in the case of the case of bandwidth reservation refusal. On the network side, the ATAP interacts with the FRP/DT. Reservation failures are used as congestion indicators to control the entering traffic and to adjust the cell priority. A simulation analysis investigates the performance of the ATAP and its interaction with the FRP/DT for two real MPEG VBR audio sequences under different bit rate anticipation approaches.

Multimedia traffic is a special traffic consisting of different components (video, voice and data) belonging all to the same application and hence being strictly temporarily bounded. The jitter impact on multimedia (MM) traffic in ATM networks is analyzed. The inter-flows jitter (IFJ) parameter, that defines the jitter between several associated traffic flows is introduced. Furthermore, the jitter and IFJ are studied under two different multiplexing schemes namely, "all in one virtual path (VP)" and "one VP for each". An IFJ recovery mechanism (IFJ-rm) is finally proposed to restore the original traffic. Simulation results for the IFJ-rm under different scheduling disciplines are presented and discussed.