WCF Timeouts Explained

An explanation of where and why to use the WCF Timeout configurations:

Client side:

• SendTimeout is used to initialize the OperationTimeout, which governs the whole interaction for sending a message (including receiving a reply message in a request-reply case). This timeout also applies when sending reply messages from a CallbackContract method.
• OpenTimeout and CloseTimeout are used when opening and closing channels (when no explicit timeout value is passed).
• ReceiveTimeout is not used.

Server side:

• Send, Open, and Close Timeout same as on client (for Callbacks).
• ReceiveTimeout is used by ServiceFramework layer to initialize the session-idle timeout.

Source: http://social.msdn.microsoft.com/Forums/en-US/wcf/thread/84551e45-19a2-4d0d-bcc0-516a4041943d/