Ž . Computer Networks and ISDN Systems 29 1998 2201–2212 First-order rate-based flow control with dynamic queue threshold for high-speed wide-area ATM networks 1 Song Chong a, ) , Ramesh Nagarajan b,2 , Yung-Terng Wang b,3 a Department of Electronic Engineering, Sogang UniÕersity, C.P.O. Box 1142, Seoul 100-611, South Korea b Performance Analysis Department, Bell Laboratories, Holmdel, NJ 07733, USA Abstract In this paper we present a new rate-based flow control scheme for ATM ABR services and analyze its performance. The Ž . proposed algorithm, which we refer to as first-order rate-based flow control FRFC is the most simple form of queue-length-based flow control. The asymptotic stability, the steady-state throughput, queue length and fairness, and the transient behavior are analyzed for the case of multiple connections with diverse round-trip delays. We also consider a novel approach to dynamically adjust a queue threshold in the FRFC according to the changes in the available bandwidth, and the Ž . arrival and departure of connections. Simulations show that the simple FRFC with dynamic queue threshold DQT effectively maintains high throughput, small loss and a desired fairness in these dynamic environments and is a promising solution for ABR flow control in ATM networks. q 1998 Elsevier Science B.V. Keywords: ATM networks; ABR flow control; Stability; Fairness; Dynamic queue threshold 1. Introduction Recently there has been a great interest in feed- back-based flow control for high-speed wide-area networking. In particular, a rate-based approach has w x been studied extensively 2,4,5,7–10 and adopted by the ATM Forum as the standard for the flow control Ž . w x of the Available Bit Rate ABR service 4,11 . The rate-based flow control problem in high-speed wide-area networks can be stated as follows. Con- ) Corresponding author. E-mail: song@globe.sogang.ac.kr. 1 Parts of this work were carried out while Song Chong was with the Performance Analysis Department at Bell Laboratories, Holmdel, New Jersey. This research was supported in part by the Sogang University Research Grants in 1997. 2 E-mail: rameshn@lucent.com. 3 E-mail: ytwang@lucent.com. sider a network with a single bottleneck link as depicted in Fig. 1. The geographically distributed sources transmit data into the bottleneck node in their path at the rate allocated by the node. In reality, the bottleneck can be any node in the network and for simplicity, we consider only a single link in the network as a bottleneck. The switch computes the rates that will be allocated to the sources. In the queue-length-based rate control that we consider in this paper, the rates are computed based on a certain function of the difference between the observed queue length and a queue threshold. In this type of ap- proach, a certain fairness in rate allocation among users is accomplished as a consequence of the queue-length control. Examples of this type can be w x found in 2,5,7,10 . The other type of rate-based flow w x control 3,9 is to compute directly rate allocations in 0169-7552r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII S0169-7552 97 00110-4