Client channel definition table
The client channel definition table (CCDT) determines the channel definitions and authentication information used by client applications to connect to the queue manager. On platforms other than z/OS® a CCDT is created automatically. You must then make it available to the client application.
The purpose of the client channel definition table (CCDT) is to determine the channel definitions used by client applications to connect to the queue manager. The channel definition also specifies the authentication information that applies to the connections.
The CCDT is a binary file. It is generated by a queue manager. The queue manager does not read the CCDT file.
On platforms other than z/OS, the CCDT is created when the queue manager is created. Client connection channels are added to the table when you use the DEFINE CHANNEL command, and their definitions altered when you issue the ALTER CHANNEL command.
You can use the CCDT to provide clients with the authentication information to check for SSL certificate revocation. Define a namelist containing authentication information objects and set the queue manager attribute SSLCRLNameList to the name of the namelist.
There are a number of ways for a client application to use a CCDT. The CCDT can be copied to the client computer. You can copy the CCDT to a location shared by more than one client. You can make the CCDT accessible to the client as a shared file, while it remains located on the server.
If you use FTP to copy the file, use the bin
option to set binary mode; do not use the default ASCII
mode. Whichever method you choose to make the CCDT
available, the location must be secure to prevent unauthorized changes
to the channels.
Platforms other than z/OS
A default CCDT called AMQCLCHL.TAB is created when you create a queue manager.
- On UNIX and Linux® systems:
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./prefix/qmgrs/QUEUEMANAGERNAME/@ipcc
- On Windows:
MQ_INSTALLATION_PATH
\data\qmgrs\QUEUEMANAGERNAME\@ipcc
MQ_INSTALLATION_PATH
represents the high-level directory in which IBM® WebSphere® MQ is installed.However, you might have chosen to use a different directory for queue manager data. You can specify the parameter -md DataPath when you used the crtmqm command. If you do, AMQCLCHL.TAB is located in the @ipcc directory of the DataPath you specified.
The path to the CCDT can be changed by setting MQCHLLIB
. If you do set MQCHLLIB
, be aware,
if you have multiple queue managers on the same server, they share
the same CCDT location.
The CCDT is created when the queue manager is created. 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.
How to specify the location of the CCDT on the client
- Using the environment variables
MQCHLLIB
to specify the directory where the table is located, andMQCHLTAB
to specify the file name of the table. - Using the client configuration file. In the
CHANNELS
stanza, use the attributes ChannelDefinitionDirectory to specify the directory where the table is located, and ChannelDefinitionFile to specify the file name.