While today’s computer networks support only best-effort service, future packet-switching integrated-services networks will have to support real-time communication services that allow clients to transport information with performance guarantees expressed in terms of delay, delay jitter, throughput, and loss rate. An important issue in providing guaranteed performance service is the choice of the packet service discipline at switching nodes. In this paper, we survey several service disciplines that are proposed in the literature to provide per-connection end-to-end peqormance guarantees in packet-switching networks. We describe their mechanisms, their similarities and differences, and the performance guarantees they can provide. Various issues and tradeoffs in designing service disciplines for guaranteed performance service are discussed, and a general framework for studying and comparing these disciplines are presented. I.

Compressed digital video is one of the most important types of traffic in future integrated services networks. It is difficult to support this class of traffic since, on one hand, compressed video is bursty, while on the other hand, it requires performance guarantees from the network. The common belief is that we are unlikely to achieve a high network utilization while providing performance guarantees to such bursty sources. In this paper, we introduce a new Deterministic Bounding Interval-Dependent (D-BIND) traffic model, together with tight analysis techniques, to explore the possibility of providing deterministic performance guarantees to VBR traffic while still achieving a reasonable network utilization. The D-BIND model consists of a family of rate-interval pairs where the rate is a bounding rate over the interval length. The model captures the intuitive property that over longer interval lengths, a source may be bounded by a rate lower than its peak rate and closer to its long-te...

Current solutions to providing statistical performance guarantees to bursty traffic such as compressed video encounter several problems: 1) source traffic descriptors are often too simple to capture the burstiness and important time-correlations of VBR sources or too complex to be used for admission control algorithms; 2) stochastic descriptions of a source are inherently difficult for the network to enforce or police; 3) multiplexing inside the network's queues may change the stochastic properties of the source in an intractable way, precluding the provision of end-toend QoS guarantees to heterogeneous sources with different performance requirements. In this paper, we present a new approach to providing end-to-end statistical performance guarantees that overcomes these limitations. We term the approach Hybrid Bounding Interval Dependent (H-BIND) because it uses the Deterministic-BIND traffic model to capture the correlation structure and burstiness properties of a stream; but unlike a...

A non-work-conserving server is one that may be idle even when there are packets available to be sent. Since they do not provide the optimal average performance, non-work-conserving disciplines were seldom studied in the past. For the guaranteed performance service class in integrated services networks, the main performance index is the end-to-end delay bound, instead of the average delay. Providing end-to-end delay bounds in a networking environment is difficult. While bounding delay in any server requires a bound on the input traffic, complex interactions among traffic streams usually distort the traffic pattern so that traffic inside the network is different from the source traffic. Previous techniques of bounding end-to-end delay in a networking environment usually start from the source traffic characterizations and iteratively "push" the traffic characterizations through the network. This does not only require non trivial analysis, but also has several important limitations. In th...

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In this paper we present algorithms for flow admission control at an EDF link scheduler when the flows are characterized by peak rate, average rate and burst size. We show that the algorithms have very low computational complexity and are easily applicable in practice. The complexity can be further decreased by introducing the notion of flex classes. We evaluate the penalty in efficiency that the classes incur to the EDF scheduler. We find that this efficiency degradation can be made arbitrarily small and is acceptable even for a small number of classes.

In this papeq we present a novel network-conscious ap-proach to the problem of end-to-end video delivery over wide-area networks using proxy servers situated between local-area networks (LAIVS) and a backbone wide-area net-work (WAN). We develop a novel and efective video deliv-ery technique called video staging via intelligent utilization of the disk bandwidth and storage space available at proxy servers. We also design several video staging methods and evaluate their effectiveness in reducing the backbone WAN bandwidth requirement. Our results demonstrate that the proposed pnxy-server-based, network-conscious apprvach provides an effective and scalable solution to the problem of the end-to-end video delivery over wide-area networks. 1

Previous approaches to supporting video on packet-switched networks include deterministic service, statistical service, predicted service, and feedback-based schemes. These schemes represent different tradeoffs in quality of service (QOS), achievable network utilization, and method of dealing with overload. In this paper, we propose a new service that attempts to strike an efficient balance with the above tradeoffs. The approach is based on deterministic guarantees with client controlled renegotiation of QOS parameters and graceful adaptation during overload periods. We evaluate the scheme using two traces of MPEG-compressed video and show that, even with simple renegotiation polices and relatively low renegotiation frequencies, high network utilization in the range of 50% to 80% can be achieved. For traffic that is bursty over long intervals, this represents a 100% to 150% improvement in network utilization compared to deterministic service. Compared to statistical and predicted se...

We develop call admission policies for statistically multiplexing prerecorded sources over a bufferless transmission link. Our model is appropriate for video on demand as well as other on-demand multimedia applications. In particular we allow users to specify when the sources begin transmission; we also allow the user to invoke VCR actions such as pause and temporal jumps. We suppose that the Quality of Service (QoS) requirement allows for a small amount of packet loss.

We present efficient schemes for scheduling the delivery of VBR MPEG-compressed video with stringent QoS requirements. Video scheduling is being used to improve bandwidth allocation at a video server that uses statistical multiplexing to aggregate video streams prior to transporting them over a network. A video stream is modeled using a traffic envelop that provides a deterministic time-varying bound on the bit rate. Because of the periodicity in which frame types in an MPEG stream are typically generated, a simple traffic envelop can be constructed using only five parameters. Using the traffic-envelop model, we show that video sources can be statistically multiplexed with an effective bandwidth that is often less than the source peak rate. Bandwidth gain is achieved without sacrificing the stringency of the requested QoS. The effective bandwidth depends on the arrangement of the multiplexed streams, which is a measure of the lag between the GOP periods of various streams. For homogene...