Anatomy of an Interchange

In an interchange, BizTalk Server receives an inbound message from a source application and sends one or more outbound messages to destination applications. In the process, it checks that documents carried in the inbound message contain valid data and performs any required conversions between the formats of the inbound and outbound documents. In a simple scenario, BizTalk Server receives a message with an XML-formatted purchase order from a customer’s purchasing application and forwards a message with the purchase order information to the SAP ERP application for processing. Both inbound and outbound processing break down into three layers: delivery, message processing, and document processing, as follows:

Inbound

• The delivery layer receives a message with the XML purchase order over the network. It decodes the message, which may involve decrypting it and checking a digital signature to verify its origin.
• The message processing layer extracts routing information (source and destination