Asynchronous Transfer Mode Communication Research Articles

Research of Asynchronous Communication Based on the 1394 Bus Network

This paper introduced the asynchronous communication mechanism in 1394 bus network, and described 1394 network communication system for building the network topology, node architecture and asynchronous transfer mode communication. We proposed a 1394 bus network asynchronous communication mechanism with high-security, high-reliability. At last it verified the communication in the network with one control computer and four remote nodes.

SWAN: a mobile multimedia wireless network

The SWAN (Seamless Wireless ATM Network) is an experimental indoor wireless network that instigates the combination of wireless access with multimedia networked computing in an indoor setting. It is based on room-sized pico-cells and mobile multimedia endpoints. It enables users carrying multimedia endpoints, such as personal digital assistants (PDAs), laptops, and portable multimedia terminals, to seamlessly roam while accessing multimedia data resident in a backbone wired network. The network model of SWAN consists of base stations connected by a wired asynchronous transfer mode (ATM) backbone network, and wireless ATM last hops to the mobile hosts. SWAN is one of the first systems to realize the concept of a wireless and mobile ATM network. Mobile hosts as well as base stations are embedded with custom-designed ATM adapter cards called FAWN (Flexible Adapter for Wireless Networking). FAWN uses off-the-shelf 2.4 GHz industrial, scientific, and medical (ISM) band radios. After giving an overview of the SWAN network model, and discussing the challenges in making ATM wireless and mobile, the article describes the first phase implementation of SWAN hardware and software. This initial implementation provides connectivity over the wireless last hop. We have investigated both native-mode end-to-end ATM communication across the wired ATM backbone and wireless ATM links, and transmission control protocol (TCP) and user datagram protocol (UDP) communication using Internet protocol (IP) over wireless ATM in the wireless link with IP forwarding and segmentation and reassemble modules at the base stations.

Fast simulation of packet loss rates in a shared buffer communications switch

This article describes an efficient technique for estimating, via simulation, the probability of buffer overflows in a queueing model that arises in the analysis of ATM (Asynchronous Transfer Mode) communication switches. There are multiple streams of (autocorrelated) traffic feeding the switch that has a buffer of finite capacity. Each stream is designated as being of either high or low priority. When the queue length reaches a certain threshold, only high priority packets are admitted to the switch's buffer. The problem is to estimate the loss rate of high priority packets. An asymptotically optimal importance sampling approach is developed for this rare event simulation problem. In this approach, the importance sampling is done in two distinct phases. In the first phase, an importance sampling change of measure is used to bring the queue length up to the threshold at which low priority packets get rejected. In the second phase a different importance sampling change of measure is used to move the queue length from the threshold to the buffer capacity.

Priority queueing strategies and buffer allocation protocols for traffic control at an ATM integrated broadband switching system

The problem of furnishing an asynchronous transfer mode (ATM) based broadband-ISDN (B-ISDN) with two bearer services supporting different grades of transfer quality is addressed. The focus is on priority bandwidth and buffer management in the ATM communications nodes (switches, multiplexers or concentrators, and expanders) in the context of a multichannel network architecture. Detailed queueing analyses and simulations and results are provided to evaluate the differentiation between traffic classes that can be achieved by different strategies. The implementation complexity of the different schemes is discussed. Various priority queueing strategies characterized mainly by different degrees of resource sharing and a general system model for performance evaluation are introduced. Performance comparisons and design tradeoffs are addressed. >

Design of a multistage self‐routing switch with a distributed cell sequence control

AbstractAs a technique for constructing the switch fabric in the ATM (asynchronous transfer mode) communication system, the self‐routing switching network has been proposed where the buffered Banyan network is used as the distribution network as well as the routing network. The features of this kind of switch are that it is of a distributed structure, being suited to the modular construction, the large capacity system can easily be realized, and the performance is stable for diversified traffic. On the other hand, it has a problem in that the order of the transmitted information (cells) is not preserved.This paper proposes anew a switch construction with time stamps attached to the cells. The cell sequence is preserved by controlling the sequence of the time stamps, and the system can be controlled in a distributed way. The feature of the method is that the cell sequence is preserved while maintaining the self‐routing property of the traditional multistage buffered switch.Also, the principle and the optimal construction are described. Basic system parameters such as the required word length for the time stamp signal are determined. The delay characteristics of the proposed system for various kinds of traffic are evaluated by a computer simulation.

ATM communications network control by neural networks

A learning method that uses neural networks for service quality control in the asynchronous transfer mode (ATM) communications network is described. Because the precise characteristics of the source traffic are not known and the service quality requirements change over time, building an efficient network controller which can control the network traffic is a difficult task. The proposed ATM network controller uses backpropagation neural networks for learning the relations between the offered traffic and service quality. The neural network is adaptive and easy to implement. A training data selection method called the leaky pattern table method is proposed to learn precise relations. The performance of the proposed controller is evaluated by simulation of basic call admission models.