This paper concerns the design of distributed algorithms for sharing network bandwidth resources among contending flows. The classical fairness notion is the so-called max-min fairness; F. Kelly [8] has recently introduced the alternative proportional fairness criterion; we introduce a third criterion, which is naturally interpreted in terms of the delays experienced by ongoing transfers. We prove that fixed size window control can achieve fair bandwidth sharing according to any of these criteria, provided scheduling at each link is performed in an appropriate manner. We next consider a distributed random scheme where each traffic source varies its sending rate randomly, based on binary feedback information from the network. We show how to select the source behaviour so as to achieve an equilibrium distribution concentrated around the considered fair rate allocations. This stochastic analysis is then used to assess the asymptotic behaviour of deterministic rate adaption proc...

Congestion control mechanisms for ATM networks as selected by the ATM Forum traffic management group are described. Reasons behind these selections are explained. In particular, selection criterion for selection between rate-based and credit-based approach and the key points of the debate between these two approaches are presented. The approach that was finally selected and several other schemes that were considered are described.

This paper describes the "explicit rate indication for congestion avoidance" (ERICA) scheme for rate-based feedback from asynchronous transfer mode (ATM) switches. In ERICA, the switches monitor their load on each link and determine a load factor, the available capacity, and the number of currently active virtual channels. This information is used to advise the sources about the rates at which they should transmit. The algorithm is designed to achieve high link utilization with low delays and fast transient response. It is also fair and robust to measurement errors caused by the variations in ABR demand and capacity. We present performance analysis of the scheme using both analytical arguments and simulation results. The scheme is being considered for implementation by several ATM switch manufacturers.

The ERICA switch algorithm has been discussed extensively in TM group in the past. However, over the last two years, the algorithm has been substantially modified. This contribution describes the current version of ERICA switch algorithm in complete detail. The algorithm achieves both efficiency and fairness, and exhibits a fast transient response. The development of the algorithm is traced, and the new approaches it uses to achieve its objectives are highlighted. Several design and implementation aspects of the algorithm are examined. In addition, several enhancements to the algorithm are proposed and studied.

Emerging indoor mobile computing environments seek to provide a user with an advanced set of communication-intensive applications, which require sustained quality of service in the presence of wireless channel error, user mobility,and scarce available resources. In this paper, we investigate two related approaches for the management of critical networking resources in indoor mobile computing environments: • adaptively re-adjustingthe quality of service within pre-negotiated bounds in order to accommodate network dynamics and user mobility. • classifying cells...

We study how to improve the throughput of high-bandwidth traffic such as large file transfers in a network where resources are fairly shared among connections. While it is possible to devise priority or reservation-based schemes that give high-bandwidth traffic preferential treatment at the expense of other connections, we focus on the use of routing algorithms that improve resource allocation while maintaining max-min fair share semantics. In our approach, routing is closely coupled with congestion control in the sense that congestion information, such as the rates allocated to existing connections, is used by the routing algorithm. To reduce the amount of routing information that must be distributed, an abstraction of the congestion information is introduced. Using an extensive set of simulation, we identify a link-cost or cost metric for "shortest-path" routing that performs uniformly better than the minimal-hop routing and shortest-widest path routing algorithms. To further improve throughput without reducing the fair share of single-path connections, we propose a novel prioritized multi-path routing algorithm in which low priority paths share the bandwidth left unused by higher priority paths. This leads to a conservative extension of max-min fairness called prioritized multi-level max-min fairness. Simulation results confirm the advantages of our multi-path routing algorithm.

Mobile computing environments that seek to support communication-intensive applications need to provide sustained end-to-end networking resources to static and mobile flows in the presence of scarce and variable wireless bandwidth, bursty wireless channel error, and user mobility. In order to achieve this goal, we present the TIMELY adaptive resource management architecture and algorithms for resource reservation, advance reservation, and network layer and end-to-end adaptation in mobile computing environments. The key novelty of our approach is the coordination of adaptation between the different layers of the network in order to solve the problems introduced by scarce and dynamic network resources. 1 Introduction Mobile computing is becoming increasingly popular because of the availability of indoor and outdoor wireless packet networks such as Wavelan, Rangelan, RAM and CDPD. In order to effectively support communication-intensive applications such as web browsing and multime...

The notion of lambda-Grids posits plentiful collections of computing and storage resources richly interconnected by dedicated dense wavelength division multiplexing (DWDM) optical paths. In lambda-Grids, the DWDM links form a network with plentiful bandwidth, pushing contention and sharing bottlenecks to the end systems (or their network links) and motivating the Group Transport Protocol (GTP). GTP features request-response data transfer model, ratebased explicit flow control, and more importantly, receiver-centric max-min fair rate allocation across multiple flows to support multipoint-to-point data movement. Our studies show that GTP performs as well as other UDP based aggressive transport protocols (e.g. RBUDP, SABUL) for single flows, and when converging flows (from multiple senders to one receiver) are introduced, GTP achieves both high throughput and much lower loss rates than others. This superior performance is due to new techniques in GTP for managing end system contention. 1.

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This paper assesses the state-of-the-art in Quality-of-Service (QoS) adaptive wireless networks and proposes new adaptation techniques that better suit application specific needs. The contribution of the paper is as follows: we propose an adaptive service comprising (i) bandwidth utility functions, which capture the adaptive nature of mobile applications in terms of the range of bandwidth over which they prefer to operate; and (ii) adaptation scripts, which enable adaptive mobile applications to program the per-flow adaptation time scale and bandwidth granularity realizing application-specific adaptive services. To maintain adaptive services in wireless packet access networks, we propose a split level adaptation control framework that operates at the network and application levels. Network level control employs a periodic probing mechanism between mobile devices and network gateways in support of utility based max--min fair resource allocation. Application level control is managed by a set of distributed adaptation handlers that operate at mobile devices realizing application-specific adaptation strategies.