Configure a binary format CCDT

The client channel definition table (CCDT) determines the channel definitions and authentication information used by client applications to connect to the queue manager. On Multiplatforms, a binary CCDT containing default settings is created automatically when the queue manager is created. You use the runmqsc command to update a binary CCDT.


Before starting

From IBM MQ Version 9.1.2, we can also create a CCDT in JavaScript Object Notation (JSON) format, and using this alternative format has some advantages over using a binary CCDT. See Configure a JSON format CCDT.

Clients on all platforms can view and use CCDTs. However the binary CCDT can only be created and modified under IBM MQ for Multiplatforms.


About this task

On Multiplatforms:

  • A binary CCDT is created automatically in the @ipcc directory under the data directory for the queue manager.
  • As well as being created automatically, the binary CCDT associated with a queue manager is kept in sync with the object definitions. When you define, alter or delete a client channel object, both the queue manager object definition and the entry in the CCDT are updated as part of the same operation.Notes:

    • The design of the IBM MQ CCDT file, is that the CCDT file is shrunk, only after all client-connection channels defined by the user are actually defined. When a client-connection channel is deleted, it is just marked as deleted in the CCDT file, but it is not physically removed.
    • To force the CCDT file to shrink, after deleting one or more client-connection channels, issue the following command:
      rcrmqobj -m QM80 -t clchltab

  • You use the runmqsc command to change the location and contents of the binary CCDT.

Clients on all platforms can view and use a binary CCDT.


Procedure

  • Create a default binary CCDT.

    On Multiplatforms, a default binary CCDT called AMQCLCHL.TAB is created when you create a queue manager.

    By default, AMQCLCHL.TAB is located in the following directory on a server:

    • On IBM i, in the integrated file system: 
       /QIBM/UserData/mqm/qmgrs/QUEUEMANAGERNAME/&ipcc
    • On UNIX and Linux systems:

      /prefix/qmgrs/QUEUEMANAGERNAME/@ipcc

      The name of the directory referenced by QUEUEMANAGERNAME is case sensitive on UNIX and Linux systems. The directory name might not be the same as the queue manager name, if the queue manager name has special characters in it.
    • On Windows:

      MQ_INSTALLATION_PATH\data\qmgrs\QUEUEMANAGERNAME\@ipcc

      where MQ_INSTALLATION_PATH represents the high-level directory in which IBM MQ is installed.

    However, you might have chosen to use a different directory for queue manager data. We can specify the parameter -md DataPath when we used the crtmqm command. If you do, AMQCLCHL.TAB is located in the @ipcc directory of the DataPath you specified.

  • Locate the CCDT:

    • On the client computer
    • At a location shared by more than one client
    • On the server as a shared file

    See Locations for the CCDT.

    1. Create a binary CCDT directly on a client machine.

      • Use the runmqsc command with the -n parameter.
      • The CCDT is created in the location indicated by MQCHLLIB, and with the filename indicated by MQCHLTAB, which is AMQCLCHL.TAB by default.
      • Important: If you specify the -n parameter, we must not specify any other parameter.

    2. Change the location.

      We can change the path to the CCDT by setting MQCHLLIB. Bear in mind that, if you have multiple queue managers on the same server, they share the same CCDT location.

  • Access the CCDT We can access the CCDT:

    See Locations for the CCDT for various examples.

  • View or edit the CCDT contents. We can view the CCDT contents with the runmqsc command:
    1. Set the environment variables to Access the CCDT
    2. Run the command runmqsc -n
    3. Run the command DISPLAY CHANNEL(*), for example

    On Multiplatforms, we can also edit the binary CCDT contents using the runmqsc command. Each entry of a CCDT represents a client connection to a specific queue manager. A new entry is added when you define a client-connection channel using the DEFINE CHANNEL command, and the entry is updated when you alter the client-connection channels by using the ALTER CHANNEL command. See runmqsc for more examples of using the command.

  • Provide clients with the authentication information to check for TLS certificate revocation.
    1. Define a namelist containing authentication information objects.
    2. In the CCDT, set the queue manager attribute SSLCRLNameList to the name of the namelist.

Parent topic: Configure client channel definition tables


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