The applications underlying a business process communicate by exchanging various kinds of documents, such as purchase orders and invoices. For a BizTalk Server 2004 application to execute a business process, it must be able to correctly process the messages that contain these documents. A message pipeline performs this processing, which can involve multiple stages. Incoming messages are processed through a receive pipeline, while outgoing messages go through a send pipeline.

BizTalk Server 2004 can work with documents that originate in many different formats. For internal processing, though, it needs to convert all documents to a single standard format. To make processing documents as efficient as possible, BizTalk Server uses XML as its internal format for processing all documents. Although many current applications understand XML documents, many others do not. Therefore, BizTalk Server needs to provide a way to convert other formats to and from XML. Other processing services can also be required, such as authenticating the sender of a message.

To handle these tasks in a modular way, several stages are combined to form a pipeline. Each stage contains one or more Microsoft .NET or COM components, and each component handles a particular part of message processing. The BizTalk Server 2004 engine provides several standard components that address the most common cases. Developers can also create custom components for both receive and send pipelines.

BizTalk Server 2004 provides some default pipelines, including a simple receive/send pair that you can use for handling messages that are already expressed in XML. You can also use the Pipeline Designer tool to create custom pipelines. This tool, which runs inside Microsoft Visual Studio® .NET, provides a graphical interface that enables you to drag components to create receive and send pipelines with the required behavior.

This section contains:

• Receive Pipelines
• Send Pipelines