This month’s column examines and evaluates various programming techniques for developing distributed applications. Our previous column outlined the requirements for a representative distributed application in the financial services domain. This application enables investment brokers to query the price of a stock, as well as to buy shares of stock. As shown in Figure 1, the quote service that ma...

Commodity processors and storage (embodied in clusters), very high-performance WAN and LAN interconnects, Linux and open source HPC and Grid software are transforming the way we develop and deploy high-performance computing resources. Concurrently, a new model of nationally integrated, tightly coupled scientific data archives and instruments is emerging. This talk outlines a new worldview of di...

This paper introduces an analytical model of an access scheme for Wide Area Network (WAN) resources. The model is based on the Transmission Control Protocol (TCP)modified Engset model of Heyman, Lakshman, and Neidhardt. The proposed model employs a Local Area Network (LAN) with arbitrary topology as the access network and is able to take into consideration files of arbitrary size. Through simul...

Very large problems with high resource requirements of both computationand communicationcould be tackled with large numbers of workstations. However, for LAN-based networks, contention becomes a limiting factor, whereas latency appears to limit communication for WAN-based networks, nominally the Internet. In this paper, we describe a model to analyze the gain of communication latency hiding by ...

Wide area network (WAN) -based distributed computing (DC) has become an active field of research, especially under the label of grid computing. On the other hand, research on WAN-based real-time (RT) DC has remained in an embryonic stage. The situation is changing, however. Continuous increase in the availability of optical channels, called lambdas, along with steady decrease of their costs, ha...

Image communication is an important component in picture archiving and communication systems (PACS) and teleradiology applications. Currently, local area networks (LANs) and wide area networks (WANs) use different technologies for image communication. Asynchronous transfer mode (ATM) is an emerging technology that can be used for both LANs and WANs. This article describes experimental results u...

This paper describes a detailed study of aggregated network traffic using time series analysis techniques. The study is based on three sets of packet traces: 175 short-period WAN traces from the NLANR PMA archive (NLANR), 34 long-period WAN traces from NLANR archive (AUCKLAND), and the four Bellcore LAN and WAN traces (BC). We binned the packets with different bin sizes to produce a set of time...

This paper describes a detailed study of aggregated network traffic using time series analysis techniques. The study is based on three sets of packet traces: 175 short-period WAN traces from the NLANR PMA archive (NLANR), 34 long-period WAN traces from NLANR archive (AUCKLAND), and the four Bellcore LAN and WAN traces (BC). We binned the packets with different bin sizes to produce a set of time...

This paper focuses on the implications of employing CORBA Middleware in today’s wireless telecommunications services and applications developments. It seeks to understand what current opportunities exist to support the use of this technology and assesses some of the performance implications that might be encountered. Discussion also revolves around the use of Component Oriented Development tech...