Orchestrations are the main entities that will house your BizTalk Server e-business solutions. They are graphically designed flowcharts with nodes of various shapes that allow you to listen for messages as well as receive, create, edit, and send them.
The simplest orchestrations are those that have one Receive and one Send shape and are bound to one receive port and one send port. You may add multiple shapes to the flowchart between, before, and after the Receive and Send shapes.
Orchestrations rely on ports to receive and send information to and from the BizTalk Messaging Engine.
The BizTalk Messaging Engine works by managing the flow of data to and from the various receive and send ports you have configured. Once you have configured and started the port (or the host instance in the case of an isolated receive port), BizTalk Server will pass the configuration to the appropriate adapter instance during run time. This configuration allows the adapter to determine how it will receive or send its particular data.
In order to have messages forwarded to an orchestration, you must bind the message's receive port to that orchestration. When a message comes in on the receive port it is forwarded to the orchestration where the BizTalk Server enacts your business process on it and sends the finalized message out through any send ports also bound to the orchestration.
Each receive port may be made up of multiple receive locations, each one with a different transport type allowing a single receive port to receive data from several locations at once. Send ports are unary, a single transport type sending to a single destination. However, BizTalk Server places no restrictions on the number of ports that may be used by a particular orchestration. If you wish to send a message to several data sources, all you need to do is bind multiple send ports to your orchestration.
You may wish to have a send port that transmits data received from a single receive location without modifying the data whatsoever. BizTalk Server lets you achieve this simple, receive/send model without creating an orchestration. To do so, the send port you wish to use must have a correlation or subscription to the message type you wish to send. This is done by adding a filter to the send port.
A filter can be added by opening the edit page for the selected adapter and selecting Filters & Maps and then Filters. Select BTS.InboundTransportLocation in the Property column and "==" in the Operator column. In the Value column, enter the receive location's address (URI) value.
Please refer to the Microsoft BizTalk Server documentation for more details on filters.