Multicast Asynchronous Transfer Mode Research Articles

Design and analysis of a growable multicast ATM switch

This work designs and analyzes a cost-effective growable multicast asynchronous transfer mode (ATM) switch that has a new grouping network structure. The proposed switch can easily be enlarged by using more stages, since both cell routing and contention resolution are designed to distribute over the switch elements. Experimental results indicate that, by allowing valid cells to enter grouping networks from two directions (the west and north sides), the modular ATM switch proposed herein not only meets the ATM performance requirements for both unicasting and multicasting but also uses fewer switch elements and has a shorter cell delay than the ATM switch.

Optimization of spare capacity in self-healing multicast ATM network using genetic algorithm

The objective of this paper is to optimize the amount of spare capacity reserved for the backup virtual paths (BVPs) in multicast asynchronous transfer mode networks. In this paper, we study the capacity and routing assignment problem arising in the design of self-healing networks using the VP concept. A major contribution of this work is to apply a genetic algorithm (GA) to the backup path search process instead of the trivial exhaustive search method. Experimental results indicate that both approaches have very comparable results in finding the multicast backup paths. Further, it also indicated that using a GA approach has a number of advantages over the exhaustive search approach, such as the computational requirement for a GA in finding good BVPs is small when compared to the exhaustive search method. A major drawback of our approach is that we cannot guarantee the finding of global optimum in real time.

An efficient cell-scheduling algorithm for multicast ATM switching systems

We propose an efficient multicast cell-scheduling algorithm, called multiple-slot cell-scheduling algorithm, for multicast ATM switching systems with input queues. Cells in an input-queueing system are usually served based on the first-in-first-out (FIFO) discipline, which may have a serious head-of-line (HOL) blocking problem. Our algorithm differs from previous algorithms in that we consider the output contention resolution for multiple time slots instead of the current time slot only. Like a window-based scheduling algorithm, our algorithm allows cells behind an HOL cell to be transmitted prior to the HOL cell in the same input port. Thus, HOL blocking can be alleviated. We have illustrated that the delay-throughput performance of our algorithm outperforms most of those algorithms that consider only the output contention resolution for the current time slot. We also present a simple and efficient architecture for realizing our algorithm, which can dramatically reduce the time complexity. We believe that the proposed architecture is very suitable for multicast asynchronous transfer mode (ATM) switching systems with input queues.

Two-dimensional shared memory multicast ATM switching architecture

Currently, the advances in the communication field are tending towards the Broadband Integrated Services Digital Network (BISDN) based on the Asynchronous Transfer Mode (ATM). Although numerous studies have been carried out in point-to-point switching systems, the point-to-multipoint switching system has gradually gained significance in recent years. To meet the requirement of the multicast service, we proposed a high-performance multicast switching system. There are easy ways to setup and release a multicast call. Only one copy of the address mapping information should be maintained in the system. The multicast cell overflow condition is trivially solved by our proposed switching architecture. We provide an overlay scheme to reduce delay needed in the multicast cell copying process. Finally, we afford a simulation result to evaluate the performance of the proposed multicast switching system.

Design issues for multicast ATM switches

Asynchronous transfer mode (ATM) is the underlying transmission system for ITU’s next-generation ISDN, Broadband ISDN. BISDN is designed to provide subscriber communication services over a wide range of bit rates from a few megabits to several gigabits. Among the services that have emerged are video-on-demand, distant learning, video conference, and so on. Many of these services are characterized by point-to-multipoint (multicast) communication. However, most ATM switches provide point-to-point (unicast) communication only. To support multicast communication in an ATM network, the ATM switch must be modified to make copies of an incoming cell and send them to different outlets. Many brilliant designs in multicast ATM switches have been proposed in the past. From these switches, it is about time that we summarize the past and look into the future. In this article, the important issues in designing the multicast ATM switches will be discussed. Three basic network fabrics for building multicast ATM switches are presented, and major considerations in constructing multicast ATM switches are elaborated.

Design of wide-sense nonblocking multicast ATM switches

Nonblocking multicast asynchronous transfer mode (ATM) switches can simplify the call admission control process and increase the external links' utilization. We derive the wide-sense nonblocking condition for multicast ATM switches based on a general Clos network. We also propose a routing algorithm to achieve wide-sense nonblocking. It is illustrated by an example that the number of required middle stages in our switch is significantly less than that of strictly nonblocking multicast switches.

Recursive copy generation for multicast ATM switching

This paper describes the structure of a multicast asynchronous transfer mode (ATM) switching node employing a recursive copy generation algorithm, based on a self-routing network with a limited copying capability and a few added elements. With the network generates only a few copies a time of an input multicast cell, the remaining are obtained by recycling the output copies to the corresponding inputs as many times as necessary. The proposed recursive copy generation is also suitable to dynamically include new destinations and to delete old ones. The performance of the proposed structure, that has been implemented in a test-bed prototype, is also evaluated in terms of throughput and delay, via computer simulation, showing a possible performance improvement for multicast traffic with respect to an equivalent unicast input traffic. The cell loss probability in such structure is also evaluated.