An Infrastructure for the Dynamic Distribution of Web Applications and Services

This paper presents the design and implementation of an infrastructure that enables any Web application, regardless of its current state, to be stopped and uninstalled from a particular server, transferred to a new server, then installed, loaded, and resumed, with all these events occurring "on the fly" and totally transparent to clients. Such functionalities allow entire applications to fluidly move from server to server, reducing the overhead required to administer the system, and increasing its performance in a number of ways: (1) Dynamic replication of new instances of applications to several servers to raise throughput for scalability purposes, (2) Moving applications to servers to achieve load balancing or other resource management goals, (3) Caching entire applications on servers located closer to clients.National Science Foundation (9986397

Introduction to Directory Services

The Directory has grown to be an important OSI application as it acts as a focal point and general support for a number of other applications. This work first points out directory requirements in the OSI framework and other OSI applications, as the Mail Handling System. The first version of the X.500 standard is then described and some Directory related issues are discussed. In particular, X.500 Directory as a database system is examined and some directory service implementations are presented

Considerations on command and response language features for a network of heterogeneous autonomous computers

The design of a uniform command language to be used in a local area network of heterogeneous, autonomous nodes is considered. After examining the major characteristics of such a network, and after considering the profile of a scientist using the computers on the net as an investigative aid, a set of reasonable requirements for the command language are derived. Taking into account the possible inefficiencies in implementing a guest-layered network operating system and command language on a heterogeneous net, the authors examine command language naming, process/procedure invocation, parameter acquisition, help and response facilities, and other features found in single-node command languages, and conclude that some features may extend simply to the network case, others extend after some restrictions are imposed, and still others require modifications. In addition, it is noted that some requirements considered reasonable (user accounting reports, for example) demand further study before they can be efficiently implemented on a network of the sort described

Design Options for Service Directories in Business Networks

Web services and service oriented architectures (SOA) are spreading in many organizations toachieve business interoperability of their intra- and inter-organizational business processes. SOA isbased on the idea that service providers develop and publish web services via standardized interfacesin directories (registries) where the services will be found and bound by service consumers. Whilethese registry structures have emerged into a standard for local SOA implementations, the questionremains how service directories should be organized in a business network, i.e. when multiple companieswith individual SOA solutions interact. This research develops a framework for the analysis ofservice directories in business networks and provides design options for combining separate and distributedservice directories. These design options are based on the range, reach, and richness of webservice markets in the business network. The framework is applied to two business network cases

Web-Services - The Next Evolutionary Stage of E-Business

Web-Services are a set of new technologies that promise to take service-oriented distributed computing to a whole new level, and eventually take e-business to the next evolutionary stage. Web-Services, in a nutshell, let organizations bridge communication gaps among their information systems, and build new software applications by stitching together existing ones. It is capable of integrating applications written in different programming languages, developed by different vendors, and running on different servers with dissimilar operating systems. Web- Services would enable companies to seamlessly connect their information systems and business processes with those of their partners and customers - thus ushering in a new service oriented distributed computing architecture. The purpose of this paper is to explore the nature of Web-Services, explain the essential concepts that enable Web- Services, and understand its major benefits and point out its shortcomings