Reliable Messaging

Reliable Messaging in Web services helps applications to send and receive messages in an efficient and secure manner amidst application, platform, or network failures. The WS-Reliable Messaging specification (WS-RM) defines a protocol and a set of mechanisms to ensure that messages are delivered reliably between two endpoints. WS-RM handles both simple and complex scenarios arising in message transmission.

Reliable Messaging capability is provided by the Reliable Messaging Core/UI features in the WSO2 feature repository, which are currently bundled by default in the Service Management feature. These features provides a Reliable Messaging tool that is used to enable WS-RM to services at global-level and service-level.

• Global-Level : Engages reliable messaging to all services. For information, see Configuring the sandesha2 Module.
• Service-Level : If you activate reliable messaging for a particular service, your configurations apply to that service only.

Service-level reliable messaging 

Follow the steps below to enable and manage reliable messaging on a service-level. 

1. Log in to the management console and click Services > List under the Main menu.
2. In the Deployed Services page that appears, click on the service to which you want to activate reliable messaging.
3. The service's dashboard opens. Click Reliable Messaging from the Quality of Service Configuration panel. 
4. Enable reliable messaging to the service by selecting Yes.
5. Change the default Reliable Messaging Sequence Configuration settings as you need.The options of the above window are as follows:

   WS-RM defines a one-way sequence. The sender (source) is called the RMS (reliable messaging source) and the receiver (destination) is called the RMD (reliable messaging destination). Therefore, for in-out operations, the RM uses two sequences. The server acts as the RMD for request messages and RMS for response messages.

   • Inactivity Timeout Interval : The maximum inactive time for any RM session. After the sequence timeout, the RM session is terminated.
   • Inactivity Timeout Measure : The unit in which the inactivity timeout interval is specified.
   • Sequence Removal Timeout : Shows the interval. If the sequence is inactive during this time period, the sequence is removed from the storage.
   • Sequence Removal Timeout Measure : The unit, in which the sequence removal timeout interval is specified.
   • Acknowledgment Interval : The time interval that the RMD uses to send the acknowledgments.
   • Retransmission Interval : The time interval, after which the RMS retransmits the message if it does not get an acknowledgment.
   • ExponentialBackoff : Whether RMS exponentially increases the retransmission time or not.
   • Maximum Retransmission Count : The maximum number of retransmits the RMS sends.

6. Click Finish after the config is done.

   The rest of the function of buttons on this window are as follows:

   • Finish : Submits the current data
   • Reset : Loads the last submitted configuration
   • Default : Loads the default RM configuration. (Click Finish to submit)
   • Clear : Clears he text boxes
   • Cancel : Goes to the main page