(A) study on rate based control of multiple congested asynchronous transfer mode (ATM) networks

Abstract

Resources of communication networks are restricted by economical or technical reasons. Unbalance between user requirements and insufficient network resources makes a serious problem, it congestion. Generally, there are three approaches to treat the congestion problem: management, avoidance, and recovery. In the information era of the future, since the communication networks will have very heavy traffic due to increments of users and transmitting data size, congestion will be more serious. Broadband integrated service digital network (B-ISDN) was introduced to provide various services in the communication network of the next generation. The asynchronous transfer mode (ATM) network was recommended to support the B-ISDN service by ITU-T, which had received considerable attention as an alternative network. In this dissertation, we consider the congestion avoidance and recovery approaches on ATM network systematically. The ATM networks provide various service categories with priority. In the sense of congestion avoidance, we present a priority scheduling algorithm to allocate the outgoing link capacity to the service categories, which guarantees the QoS of each category. In the proposed algorithm, the service rate of each category is adjusted periodically, based on two proposed control schemes: robust with respect to the real allocated time and pole placement. Also, we show how the algorithm can be used for the call admission control (CAC) for the available bit rate (ABR) service category. In the sense of congestion avoidance and recovery, the ABR service category in ATM networks allows the feedback flow control mechanism to dynamically allocate idle bandwidth of the network to users fairly and to control the network congestion rapidly. Although each user has different sending capacity, the widely used max-min fairness criterion does not consider the differences. We suggest a new fairness criterion to provide fair service rates to all active ABR users, which are ...