An efficient adaptive bus arbitration scheme for scalable shared-medium ATM switch
Most commercial asynchronous transfer mode (ATM) switches are of the shared-medium type and are based on the well-known TDMA bus arbitration scheme. This is primarily due to the ease of implementation of shared-medium switches. However; ATM switches of this category, suffer from a major drawback - they are not scalable for large sizes because they require a bus running N times faster than the ports where N is the switch size, i.e. the number of input ports). Furthermore, ATM switches that are based an the TDMA bus arbitration scheme suffer from low performance when the offered traffic is bursty. In this paper, a new approach to the design of scalable shared-medium ATM switches, which are capable of operating efficiently under bursty traffic, is introduced. The main features of the proposed switch are the following: (1) It uses the broadcast bus topology. (2) There is no need to have a bus running N times faster than the ports. A bus of any bandwidth can be used. (3) It uses a fully distributed bus arbitration scheme. (4) The MAC algorithm, which is implemented at each input port has a time complexity, which is in the nanoseconds range and is independent of the switch size N. (5) It is capable of operating efficiently under bursty traffic conditions. (6) It is based on the use of learning automats in order to allocate the bandwidth to the input ports according to their needs. (C) 2001 Elsevier Science B.V. All rights reserved.
scalability atm switches distributed bus arbitration adaptive arbitration