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Author's profile photo Christoph Claus

Enable Load Balancing for RFC Clients

Every year, a lot of solutions based on the RFC communication protocol are certified by the SAP Integration and Certification Center (SAP ICC). Companies that have an S-User can download the needed connectors to implement such an RFC integration from SAP Service Marketplace: The most popular connectors are SAP Java Connector, SAP Connector for Microsoft .NET and SAP NetWeaver RFC Library.

Using these connectors, RFC clients can connect with a dedicated SAP Application Server to call BAPIs and RFC modules, or to send an IDOC message. However, if this contacted Application Server is down for some reason, the RFC call would fail, even if several other Application Servers would be up and running.

RFC Clients can easily make use of the Load Balancing mechanism of SAP NetWeaver; it’s only a matter of configuration. You just have to fill different connection parameters. Therefore, SAP ICC highly recommends supporting the following two methods to connect an RFC client with an SAP System:

  1. Connect to an SAP System through Group Logon via an SAP Message Server:
    This should be the preferred method, if the SAP landscape runs an SAP Message Server. With that, load balancing takes place, and calls are routed automatically to a running Application Server.

    The following RFC connection parameters must be filled: MSHOST, MSSERV, SYSID, GROUP
  2. Connect to an SAP System using a specific Application Server:
    If SAP Message Server is not available, then you have to connect to a specific Application Server.
    The following RFC connection parameters must be filled: ASHOST, SYSNR

So please make sure, that your RFC connection configuration screen / dialog supports all the parameters of the 2 connection methods mentioned above. Your customer would then tell you the appropriate connection method and parameters.

More details can be found in the documentation of the respective SAP connector:

  • SAP Java Connector:
    Open the included javadoc-documentation of the interface “DestinationDataProvider”.
    Check details of “Load balancing connection to a group of SAP application servers via a message server” and “Direct connection to an SAP application
    server instance”.
    Here, the parameter SYSID is called R3NAME.
  • SAP Connector for Microsoft .NET:
    Open the documentation “NCo_30_ProgrammingGuide.pdf” on page 46.
    Check details of “Group Logon” and “Application Service Logon”.
  • SAP NetWeaver RFC Library:
    Open the documentation “NW_RFC_SDK_Guide.pdf” on page 16 and 20.
    Check details of “SAP System using Load Balancing” and “SAP System using a specific application server”.

If you have any questions or need further assistance, please contact your SAP ICC Integration Consultant at

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      Author's profile photo Former Member
      Former Member

      Christoph Claus,

      Thanks for sharing this document... This helps me to get the answers to many questions that I have on how to achive the load balancing.

      Kind Regards,