What is IT Architecture? In short, it is a conceptual technical framework which examines the major components that make up a modern enterprise's overall IT infrastructure and how these components are suppose to fit and inter-operate together. Such components include software, hardware, standards, protocols, security, routing, addressing, storage, backup, database, remote access, encryption, to name a few. Realistically, most sites develop like most cities - constantly renewing streets, highways, rails, and adding on subdivisions. As with IT infrastructures, it is rare that the entire infrastructure is bulldozed and a new one built from ground up. Consider the following adapted loosely from RFC1958:Architectural Principles of the Internet.

In most operating environments there are numerous heterogeneous systems which must be supported by design. There are multiple types of hardware, data transmission speeds, and hosts ranging from small single processor workstations to large multiprocessor servers. There are multiple types of application protocols running which range from the simplest such as remote login up to the most complex such as clustered and distributed databases.

Without a comprehensive architecture, an organization will face a higher rate of system performance problems and failure as well as suffer from a more rapid obsolescence cycle than that which is necessary. One goal of a well thought out IT architecture is to ensure that all pieces inter-operate together in manageable manner and that system expansions can be achieved without undue component obsolescence.