This application style can be quite simple, but because application servers usually have very low latency requirements, a large amount of time and effort may be needed for performance tuning.

Packaged Integration
The Packaged Integration BizTalk application style isn't as common as the other application styles. Here an organization that sells a primary software product provides its customers with the integration interface to that product by packaging the interface into BizTalk solutions. The organization may or may not provide BizTalk Server with a license to its primary product. The complexity of this style of application varies widely based on how the integration with the primary software product is done as well as the potential for a multitude of deployment requirements for the BizTalk artifacts.

Workflow
The Workflow application style is a common application style that can be very complex. Its complexity varies with the amount of human interaction and the level of flexibility that must be built into the application. This application style is defined by widely varying human interaction in a business process. It is focused on improving a previously manual or semi-automated business process and increasing its automation while improving how people interact with the process.

This application style can involve recursive sub-processes, roles, re-assignments, and complex business rules, which means that the BRE might be used as well as other user-focused technologies such as Business Activity Monitoring, HTTP, InfoPath, Windows SharePoint Services, the BizTalk SharePoint Adapter, and the BizTalk SQL Adapter.

Hub
The Hub application style is a common but often complex application style. A Hub's complexity will vary based on the number and complexity of the messages flowing through it as well as the non-functional requirements associated with it such as availability, scalability, message priority, and duplicate message detection. This application style involves integrating multiple internal and/or external applications usually in a near-real-time manner. Hubs are often focused on business events and messages as opposed to complex business processes.

This application style usually contains many different message types and consequently many different transformations to map between the message types. BRE and Business Activity Monitoring use are also common in this application style.

Hub applications can be realized by the addition of multiple BizTalk solutions in the same BizTalk farm or they can be well-thought-out entities that are planned from the solution's inception. If the Hub is planned it may involve a new database that the Hub updates as messages pass through it. Example databases include an index database that contains "pointers" to data in other systems, a database that contains a subset of data from other systems, and a database that provides caching services.

Service Oriented Architecture Enabler
The Service-Oriented Architecture (SOA) Enabler application style can be quite complex, not because of the implementation but because it's part of an organization's move to service orientation, which can often be difficult. This application style is defined by BizTalk enabling an organization to move towards a Service Oriented Architecture, usually with a focus on Web Services. A focus on Web Services is neither required nor desirable in all cases. This application style often involves complex business modeling, enterprise security model design, Web Services protocols, heavy enterprise architecture and business involvement, and perhaps most importantly, a mind shift among an organization's staff on how to design, implement, and manage applications. (see Figure 1)

BizTalk is an excellent fit for this application style if one subscribes to the belief that SOA doesn't just mean SOAP over HTTP. It's an excellent fit because BizTalk includes a large number of application and protocol adapters that can be used to integrate with many different systems. This means those systems can be brought into the SOA without having to write custom components to communicate with them or act as a façade for them.

This application style can start off with only a handful of services but if the value of those services is high, the number of services provided through BizTalk can quickly increase.

Business Process Management
The Business Process Management (BPM) application style is the pinnacle of BizTalk applications styles and can be very complex. Its complexity varies in direct relationship with the complexity of the business process being automated. This application style is defined by the many business processes, workflows, and integrations being implemented in BizTalk along with heavy business user involvement. It requires significant Business Activity Monitoring use for realizing information about the processes, workflows, and integrations, and an overwhelming desire on the part of the organization to improve those business processes, workflows and integrations continuously.

A later stage of this application style is to improve the business process, workflows, and integrations so they can be modified at runtime based on the near-real-time information being gathered from Business Activity Monitoring and other sources.

Determining When Biztalk Can Be Used
Now that you're familiar with several applications styles that can be built with BizTalk Server, a set of questions will be introduced to provide the reader with a starting point for determining if BizTalk Server can be used by the reader's organization or project. If the answer to several questions is Yes, then BizTalk should be considered.

SCENARIO QUESTIONS

• Does your solution need to scale easily as message volume increases over time?
• Do you have compliance (auditing, legal, etc.) requirements?
• Do you have a business process that demands never losing a message?
• Does your environment make heavy use of business rules or use business rules that change frequently?
• Do you have many disparate technologies and systems that have to be integrated?
• Do you have an XML-heavy environment including SOAP, XSD, XSLT and XML over HTTP?
• Do you want to eliminate your point-to-point integration solutions?

TECHNOLOGY CULTURE QUESTIONS

• Is your development team interested in a software framework for integration and business process automation?
• Does your development team have strong .NET development experience?
• Will your development team embrace non-coding solutions to your organization's business problems?
• Does your development team consist of self-starters who are willing and able to learn many new things at once?
• Do you have a practical IT operations staff that is willing to learn a new tool because over time it will simplify its work?

BUSINESS CULTURE GUIDELINES

• Do you have a business that doesn't look for huge return on investment on the first tactical application implementation?
• Is the business willing to invest in long-term solutions?
• Does your business want to improve its business processes and learn more about its business?
• Does your business want to partner with IT?

Summary
Several styles of applications that can be built with BizTalk were presented in this article. They vary in complexity and characteristics but BizTalk's features provide a framework for implementing them all. In a subsequent article, BizTalk's core features and their benefits will be reviewed.