Implementing RoutingAgent Agents
The RoutingAgentFactory and RoutingAgent classes are the base classes for transport agents that are designed to run on a Microsoft Exchange Server 2010 computer that is running the Hub Transport server role. The RoutingAgent class provides the following two events for which you may implement handlers in your Hub Transport agent:
OnSubmittedMessage This event occurs after the message is taken off of the submit queue. Use the OnSubmittedMessage event if your Hub Transport agent does not require content conversion.
OnRoutedMessage This event occurs after the server routes the message to the next hop and performs content conversion, if required. The server may use a greater amount of resources to process each message in the OnRoutedMessage event than the OnSubmittedMessage event because the server will perform any necessary content conversion and determine the next hop in the route for the message before it executes the code in the OnRoutedMessage event handler.