Messaging layer is composed of channels. A channel is a component that processes a message in some way. Channels are the core abstraction for sending messages to and receiving messages from an Endpoint.
Message Structure:
WCF uses messages to pass data or exchange information from one point to another. All messages are SOAP messages. The basic structures of a SOAP message are made up of three components.
SOAP Envelope:
The SOAP envelope is a container for the two most important pieces of a SOAP message, the SOAP header and the SOAP body. A SOAP envelope contains several pieces of key information in the form of elements.
SOAP Header:
Using a SOAP header, we can pass useful information about the services to the outer world if needed; it's just for information sharing. Any child elements of the header element are called "header blocks". This provides a mechanism for grouping logical data together.
SOAP Body:
This element contains the actual SOAP message for communication with the SOAP receiver; a message can contain zero or more bodies. Any information intended to be exchanged when the message reaches the intended destination goes in the message body.
