Business architecture is one of the four layers of an IT architecture.  The other three layers are information, applications and technology. Business architecture describes the business processes utilized within the organization.

If one looks at the dictionary, architecture is define as "a unifying or coherent form or structure."  As one of the layers of the IT architecture, it is extremely important to know and understand the business architecture to come up relevant software systems.  Aside from the technical aspects, information system architects should be concerned with the content and usage of the systems they are building for the business organization.

It cannot be argued that today’s business is very tightly intertwined with information system technology.  Even for the small home business, software applications are very much in use.  It is impossible for multinational corporations to operate without business software.

A good analogy for business architecture would be architecture of real buildings.  Building architects need to understand the purpose of the building before doing the design.  If they are designing homes, they need to also understand certain patterns and trends like behavior of families.  If they design skyscrapers, they need understand weather conditions among other things.

In the same manner, a business architects need to understand basic business concepts.  They need to know the requirements of the business.  For example, if the business is about manufacturing of furniture, they need to know where to get the raw materials and how much they cost.  They also need to know who the target clients are and how to deal with competition.

Business architects should also determine the scope of the business.  How can the company grow and branch out to areas or countries?  What is the expected annual growth based on product manufacture and sales revenues?

There are many more considerations to account and once all these are in one place, a business architect starts drawing the design. The design must have to cater to all aspects of the business.  There is no trivial aspect in business as tiny details can create huge impact on the organization as a whole.

As one of the layer of the IT architecture, the business architecture is the very framework where the other layers, information, application and technology are based on.  Business data constitute information which may be used by business software applications which are executed by hardware technology.  All these other layers operate within the business architecture framework.

Software applications are developed to simulation real life activities.  Manual transactions like recording sales and revenues which in the past involved tallying the data in books are automated with the use of business software. 

Many business application softwares have been developed to adapt to the business architecture.  There are many private application software developers selling highly customizable software packages to cater to the needs of an organization.  Such technologies as Enterprise Resource Planning (ERP), Customer Resource Management (CRM), Advance Planner and Optimizer (APO), Supply Chain Management (SCM), Business Information Warehouse (BIW), Supplier Relationship Management (SRM), Human Resource Management System (HRMS) and Product Lifecycle Management (PLM) among others are can all be customized based on the requirements as indicted in the business architecture.

The nature of business is fast evolving.  Many traditional businesses have evolved from a local place to global proportions.  One mobile phone has evolved from wood pulp mills to rubber works to what today is perhaps one of the global leaders in technological innovations.  Some insurance companies also consider themselves banks and vice versa.  These complex business evolution need to be tracked so appropriate changes in the business architecture can also be taken care by the information systems architects.