ABR service is currently standardized to handle applications of data traffic in ATM network. As a flow control method, the rate-based flow control has been adopted and applied to manage the ABR service. Several control methods have been proposed, and the EPRCA is selected as one of the control methods by the ATM Forum. EPRCA is an excellent algorithm, but when the EPRCA is applied to the ATM network, several problems occur. One of the problems is the beat-down problem, which gives unfair allocation of transmission rate to connections. We propose a new control method which solves the beat-down problem. We will show that, by our proposed method, (i) the ACR is given fairly to every connection compared to the conventional method, and also (ii) the throughput is fair for both long-hop and short-hop connections, (iii) the ACR is proportional to the throughput, and finally (iv) the total throughput is larger than that of the conventional method. The fairness of the throughput in (ii) is measured by the fairness index. In (iii), being proportional means that the allocated ACR is close to the throughput and it is measured by the proportion index. The performance is evaluated by computer simulation.

The Available Bit Rate (ABR) service of Asynchronous Transfer Mode (ATM) networks employs explicit rate notification algorithms to ensure better and fair distribution of available bandwidth among contending sources. The Enhanced Proportional Rate Control Algorithm (EPRCA) is one of the explicit rate control algorithms recommended by the ATM forum. In this paper, we identify deficiencies and problems associated with EPRCA and show that these cause unfairness in bandwidth utilization by the contending sources. We propose modification in EPRCA and call it Modified Enhanced Proportional Rate Control Algorithm (EPRCAM). We will argue and show through simulation results that EPRCAM leads to better link utilization and fair bandwidth allocation among contending sources. In our simulation model, EPRCAM results in as high as 97. 8% link utilization without cell loss.

The classical max-min policy has been suggested by the ATM Forum to support the available bit rate (ABR) service class. However, there are several drawbacks in adopting the max-min rate allocation policy. In particular, the max-min policy is not able to support the minimum cell rate (MCR) requirement and the peak cell rate (PCR) constraint for each ABR connection. Furthermore, the max-min policy does not offer flexible options for network providers wishing to establish a usage-based pricing criterion. In this paper, we present a generic weight-based rate allocation policy, which generalizes the classical max-min policy by supporting the MCR/PCR for each connection. Our rate allocation policy offers a flexible usage-based pricing strategy to network providers. A centralized algorithm is presented to compute network-wide bandwidth allocation to achieve this policy. Furthermore, a simple switch algorithm using ABR flow control protocol is developed with the aim of achieving our rate allocation policy in a distributed networking environment. The effectiveness of our distributed algorithm in a local area environment is substantiated by simulation results based on the benchmark network configurations suggested by the ATM Forum.

Broadband Integrated Services Digital Network (B-ISDN) is intended to provide various services in telecommunications like voice, video, and data communication. For realizing the B-ISDN network, Asynchronous Transfer Mode (ATM) is one of several data transfer technologies that are proposed and currently being developed. Several flow control methods have been proposed for data cell traffic in ATM network. One of the feedback control mechanisms is credit-based flow control that is proposed to handle an Available Bit Rate (ABR) traffic. The credit based mechanism is applied in Local Area Network (LAN) and usually uses static buffer allocation method. When the conventional credit-based algorithm is applied in the LAN system, the problems such as low utilization of node buffer and large delay of source data will occur. In this paper, we propose a new algorithm that is called stop and release credit method to make credit-based flow control more effective. According to simulation results, proposed method will make high utilization of node buffer and small delay of source data.

In this paper, a new two-level flow control scheme using VP credit-based control and stop-and-go rate control for Asynchronous Transfer Mode (ATM) networks is presented. Since the proposed scheme does not require any information on traffic characteristics, we propose to apply such a flow control scheme to the best effort traffic that requires no band-width guarantee from the network. The proposed flow control scheme can efficiently use the leftover bandwidth after the guaranteed traffic has been satisfied. Therefore, high bandwidth utilization can be achieved. Furthermore, cell loss can completely be avoided by the lower-level credit-flow control done on a per VP basis. On top of this, a higher-level Explicit Congestion Notification (ECN) rate control is employed to avoid any performance degradation. Simulations have been performed to verify the effectiveness of the proposed scheme. It is found that the average end-to-end delay of our proposed scheme is better than that of the original VCFC scheme [1]. In addition, there is also a tremendous saving in the memory required when compared with the VCFC scheme.