Solution Architecture for N-Tier Applications

This paper defines a service-oriented solution architecture for n-tier applications (SANTA), primarily for Web-based distributed systems. Most conventional Internet applications have been built on three tiers - Web, application, and database tiers as described in the predominant 3-tier architectural style on both Java EE and .Net platforms. However, a number of leading-edge technologies have matured, which need to be incorporated into the logical solution architecture, such as portal, process choreography, business rule engine, enterprise service bus, Web services, service composition, etc. A new service-oriented model is proposed in this paper, to extend the traditional 3-tier architectural style and position the emerging technologies/products in the right places in the architecture structure. This new architecture model comprises a stack of six interrelated layers, coupled with six vertical pillars. The six layers are access & integration, business process, composite services, services & components, integration & communications, and enterprise resources layer. The runtime infrastructure pillars are composed of the operational management, security, and hosting environment pillar, whereas the development process pillars consist of the application & service frameworks, crosscutting aspects & patterns, and modeling & development tools pillar. This holistic application architecture framework is a systematic taxonomy of major technical constituents of a distributed application in a service-oriented paradigm. Part of this comprehensive model has been extensively utilized in one form or another to design various SOA solutions in different industry sectors