TCP/IP connections

TCP/IP can be used for the connections between the IMS™ TM resource adapter and IMS Connect in both distributed and z/OS® environments.

When your application is on a distributed platform, the connection between the IMS TM resource adapter and IMS Connect must be a TCP/IP connection. For example, if the IMS TM resource adapter is installed on WebSphere® Application Server on Windows®, AIX®, Solaris, Linux®, Linux for z/OS, or HP-UX, the IMS TM resource adapter must connect with IMS Connect using TCP/IP connections. You can also optionally use TCP/IP connections if the IMS TM resource adapter is installed on WebSphere Application Server for z/OS.

TCP/IP connections to IMS Connect are associated with an indentifier called the client ID. IMS Connect ensures the uniqueness of these client IDs for all of the socket connections to it.

There are two types of TCP/IP connections to IMS Connect: The client ID is determined differently for the two types of socket connections.

Dedicated persistent socket connections

In the case of dedicated persistent socket connections, the client ID value is provided by the application. Typically, a dedicated persistent socket connection is used (or re-used) serially by a single application. However, a dedicated persistent socket connection can also be used serially by multiple applications that obtain the socket using the same client ID. If different applications attempt to use a dedicated persistent socket connection using the same client ID at the same time, the attempt by the first application will succeed but subsequent attempts by other applications while the first application is still using its connection will receive duplicate client errors (DUPCLNT) from IMS Connect.

A duplicate client error can also occur when an application that obtains a dedicated persistent socket connection using a given clientID runs in an environment in which dedicated persistent socket connections can originate from multiple WebSphere Application Server instances. For example, an environment that has multiple WebSphere Application Server instances managed by a workload manager might encounter duplicate client errors. It is strongly recommended that your application not be deployed to this type of environment if it uses a dedicated persistent socket connection.

Dedicated persistent socket connections are intended to be:
  • Serially re-usedby applications
  • Used in an environment where a single instance of WebSphere Application Server is connected to a single IMS Connect. There are some situations where a single instance of WebSphere Application Server can be connected to multiple instances of IMS Connect. In this configuration, if Sysplex Distributor is being used between WebSphere Application Server and IMS Connect the following interactions are not supported:
    • 2 phase commit recovery
    • IMS conversational transactions
    In addition, you may not be able to retrieve all available output messages using SYNC_RECEIVE_ASYNCOUTPUT_SINGLE_NOWAITinteractions when using multiple IMS systems without Super Member. For more information please refer to the IMS OTMA User Guide and Reference.

Shareable persistent socket connections

Shareable persistent socket connections use client IDs that are generated by IMS Connector for Java™. These client IDs are not visible to the application that is using the shareable socket. Shareable persistent socket connections can be used serially by multiple applications and do not have the limitations described above for dedicated persistent socket connections.

Establishing dedicated persistent socket connections

To establish dedicated persistent socket connections:

Establishing shareable persistent socket connections

To establish shareable persistent socket connections:


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