Asynchronous transfer mode traffic management for multi-priority video transmission

Existing Asynchronous Transfer Mode (ATM) traffic management solutions are not ready to handle the congestion problem of emerging content-based, multi-priority video transmission systems. Variable Bit Rate (VBR) video over ATM faces video quality degradation problems due to loss during congestion, since loss causes cell or frames to be dropped randomly. Research in this area has proven that usage of priorities provides better loss control. Current ATM traffic management model supports only two levels of priority classes and is completely network performance oriented. The main assumption of this research is that the real-time video traffic is content based coded and consists of several video objects. A single video source with various video objects introduces the need for multiple priorities. Multiple levels of priority classes are created according to the content information of real-time video traffic.;The main objective of the research is to develop a new ATM traffic management model that will handle the loss problem of multi-priority video transmission systems. This issue covers several aspects of ATM and multimedia networking such as video application layer, ATM adaptation layers, traffic management and buffer management. A multi-priority ATM traffic management model that includes a new priority cell mapping algorithm, a new adaptation layer definition, and a new multi-priority buffer access control algorithm is proposed in this research.;Multi-priority loss control improves video quality by increasing full transmission ratio for higher priority traffic. In this way, the loss is not eliminated, but its effects are shifted to lower priority objects. This reduces randomness in loss. This model supports content based transmission, which defines a semi-application object-aware traffic management as opposed to only connection or cell level management. The system is an integrated model that combines buffer management with the appropriate traffic management and network layer functionality. Especially, next generation content-based coded video applications will benefit from the proposed model. Currently there exists no method for managing a single connection for multi-priority video traffic over ATM networks. This model is new and addresses the essential transmission requirements of near future multi-priority video coding systems over broadband networks.