Summary

We began this chapter with the focus on an organization's business process expressed in the BizTalk Orchestration Designer. BizTalk Messaging provides a mechanism to instantiate a new instance of the XLANG schedule when a message arrives at the port and then deliver this message to the business process. First we demonstrated this with a simple example. In a real business scenario, we are almost always required to integrate two or more business processes. A business process at some point sends out a message to a second business process and then waits for a response. The second business process then sends a response back to the source process. On receiving the response, the source business process proceeds to completion. This process of returning a response message back to the source schedule is called correlation.

Correlation in BizTalk Server is accomplished by using a return address in the body of the message. The destination business process must retain this return address and use this information to return the response back to the original schedule that sent the message in the first place. We demonstrated this by providing examples for both HTTP-based correlation and non-HTTP-based scenarios. The HTTP-based scenario showed an example where a BizTalk Server was on both the sending and receiving end. The second example demonstrated correlation with BizTalk Server on only the source end with a non-BizTalk external system.