Software system architecture is collection of viewpoints. The types of viewpoints depends on the type of systems. Software system architecture for a typical web application contains information and functional views primarily focuses on the structural (or static) representation of the system and the deployment, concurrency and operational views are the behavioral (or run-time/dynamic) representation of the system and the development view is guidelines. Views are instance of viewpoints. Viewpoint is a set of standards, guidelines, templates, patterns for constructing a view.
The functional viewpoint represents the business processes and function elements of the system. It is mandatory for all web development projects since all web projects are executed to meet a set of functional requirement.
It represents the data and flow of the data within the system. The data or information is integral of the web system.
The typical web environment contains minimum a web server with internal disk, domain name server, web browser, inter network or intra network. The environment could be complex for a transaction application. It contains quite few infrastructure components like web server, router, switches, firewall, application server, domain name server, intrusion detection devices, messaging services, storage management systems, load balancer, ssl accelerator, external cache devices etc. It is essential to understand the deployment view of the system upfront during the architecture definition phase of the software development life cycle.
In an enterprise environment, there are set of standards, policies, patterns, anti-patterns, reference models, lessons learned, domain knowledge, reference architecture and etc. The development team is expected to reuse the existing references. These artifacts are provided to the application developed team by the centralized architecture team. With recent success of the outsourcing development model, the development viewpoint is required to be part of the architecture.
The functional elements of the system are to be served simultaneously for concurrent users in the web environment. It is required to study the behavior of the concurrency structure of functional elements. It enables to create the necessary environment setup like thread configuration for the operational viewpoint.
The gap between the application development process and the infrastructure management process is quite significant in the industry in spite of the well known IT infrastructure management frameworks like ITIL being in place and adapted widely. The longevity, sustainability, maintainability of the system are determined how the operation views are analyzed and designed during the architecture phase of the project. It may be optional if the web application is developed for a limited time.