In order to cope with time-varying conditions in networks with no or limited QoS support like the current Internet, schemes have been proposed for real-time applications to dynamically adjust the traffic source's transmission rate. However, employing adaptive rate control may not be sufficient to prevent or handle network congestion. As most of the real-time applications are based on RTPKJDP protocols, an issue of possibly unfair sharing of bandwidth between TCP and UDP applications has been raised. In this paper, we propose a scheme called R3Cp+ that integrates several control mechanisms to maximize the delivery performance of real-time continuous media over networks without QoS support. Simulation results show that Recursive Least Square (RLS)-based prediction makes a good use of the past measurement in forecasting the future condition that can effectively avoid and cope with network congestion. It also shows that the scheme achieves reasonably friendly resource sharing with TCP connections.

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Abstract-In this paper, we propose a framework for real-time multimedia transmission in asynchronous transfer mode (ATM) networks using an efficient traffic scheduling scheme called multilayer gated frame queueing (MGFQ). MGFQ employs only one set of FIFO queues to provide a wide range of QoS for real-time applications. We also propose special cell formats for real-time multimedia transport and a hybrid design to allow MGFQ to combine its scheduling scheme with Age Priority Packet Discarding scheme. For this hybrid design, the cell level performance as well as the packet level QoS can be improved at the same time. Simulation results show that this hybrid design will be useful for packetized voice and progressive layer-compressed video transmission across the backbone networks. With the presented framework and the MGFQ algorithm, real-time multimedia traffic streams can be much better supported in terms of cell/packet delay and jitter.

In this paper, we propose an efficient scheduling scheme called Multi-layer Gated Frame Queueing (MGFQ) for real-time traffics over ATM networks. ATM switches equipped with function of MGFQ which employs only one set of FIFO queues can provide real-time multimedia communication with a wide range of QoS requirements. In addition, a hybrid design which combines MGFQ scheme with Age Priority Packet Discarding (APPD) scheme is proposed to enhance packet level QoS. The simulation results show that the cell level performance as well as the packet level QoS can be improved simultaneously when applying this hybrid design.