Client / Server Configuration in a Next Generation Internet Environment : End - User , Developer , and Service Provider Perspectives
چکیده
—This paper discusses variations in client/server configuration, for current and Next Generation Internet applications, from the perspective of end-users, application developers and service providers. An empirical study, which evaluates the performance of a typical Internet based business scenario, provides support for the argument that delegating functionality to clients offers a significant benefit to end users and service providers, thereby potentially justifying additional development effort. In traditional client-server systems, the majority of computation and data management is performed by the server, with a thin client providing a presentation layer to the user. This has occurred because client devices, especially those that are mobile or embedded, have lacked the computational power required to support client-side application services [1]. Furthermore, managing a centralised server is simpler and more convenient from an administrative perspective, than dealing with clients that provide application services. However, with advancing miniaturisation and the improvement in communications technology, client device limitations are becoming less of a consideration when architecting the distribution of responsibility between client and server in a distributed application. For example, mobile devices such as Intel XScale based PDA's have CPU's running at hundreds of megahertz with 64MB or more of program memory. Current generation mobile phones are able to run distributed application code using standardised platforms such as Java 2 Micro Edition (J2ME) [2], Symbian OS [3], and .NET Compact Framework [4]. Nevertheless, the move to richer client functionality has been slow, with tension existing between the needs of various stakeholders such as application users, developers and service providers. This is exacerbated by the increasing diversity of the Next Generation Internet (NGI) [5], where devices are ever varying along a number of dimensions such as screen size, form factor, processing speed, permanent storage capacity, and power consumption. Given this changing communication landscape, the rest of this paper discusses the resultant effect on the configuration of client-server applications. Sections II, III and IV begin by studying the perspective of the various stakeholders (user, service provider and developer), with section V providing support in the form of an empirical study of specific client-server configurations. Based on these findings, this paper goes on to argue that the benefits to application users and service providers are substantial enough that the increased development effort associated with heavier client solutions is justified in some circumstances. Consequently, further research should explore techniques for supporting the dynamic configuration of client-server applications, in order to utilise …