Multicast Communication Information object properties

We can set attributes for Multicast communication information objects.

The following tables list the attributes that we can set:

For each attribute, there is a brief description of when you might need to configure the attribute. The tables also give the equivalent MQSC parameter for the ALTER COMMINFO and DISPLAY COMMINFO commands. For more information about MQSC commands, see The MQSC Commands in the IBM MQ online product documentation.


General page

The following table lists the attributes that we can set on the General page of the communication information object properties dialog.

Attribute Meaning MQSC parameter
Communication Information Read only after it has been defined. The name of the communications information object. The name must not be the same as any other communications information object name currently defined on this queue manager. For more information, see Rules for naming IBM MQ objects in the IBM MQ online product documentation. COMMINFO
Type Read only after it has been defined. The type of the communications information object. The only type supported is MULTICAST. TYPE
Description Plain text comment. The description provides descriptive information about the communication information object when an operator issues the DISPLAY COMMINFO command. For more information, see DISPLAY COMMINFO in the IBM MQ online product documentation.

The description must contain only displayable characters. The maximum length is 64 characters. In a DBCS installation, it can contain DBCS characters (subject to a maximum length of 64 bytes).

Note: If characters are used that are not in the coded character set identifier (CCSID) for this queue manager, they might be translated incorrectly if the information is sent to another queue manager. 		DESCR
Group address The group IP address or DNS name. It is the administrator's responsibility to manage the group addresses.

It is possible for all multicast clients to use the same group address for every topic; only the messages that match outstanding subscriptions on the client are delivered.

Use the same group address can be inefficient because every client must examine and process every multicast packet in the network. It is more efficient to allocate different IP group addresses to different topics or sets of topics, but this requires careful management, especially if other non-MQ multicast applications are in use on the network. The default value is 239.0.0.0.

 GRPADDR
Port The port number to transmit on. The default port number is 1414 PORT
Message history The maximum message history is the amount of message history that is kept by the system to handle retransmissions in the case of NACKs (negative acknowledgments).

A value of 0 gives the least level of reliability. The default value is 100 messages.

 MSGHIST
Coded character set ID The coded character set identifier that messages are transmitted on. Specify a value in the range 1 through 65535, or set it to As published which is the default value.

The CCSID must specify a value that is defined for use on your platform, and use a character set that is appropriate to the platform. If we use this parameter to change the CCSID, applications that are running when the change is applied continue to use the original CCSID. Because of this, you must stop and restart all running applications before you continue. This includes the command server and channel programs.

To do this, stop and restart the queue manager after making the change. This parameter is valid only on AIX , HP Integrity NonStop Server, HP-UX, Linux , IBM i, Solaris, and Windows. For details of the supported CCSIDs for each platform, see Code page conversion in the IBM MQ online product documentation.

 CCSID
Encoding The encoding that the messages are transmitted in.

  • As published. This is the default value.
  • Reversed
  • Normal
  • S390
  • TNS
  • encoding
ENCODING
New subscriber history The new subscriber history controls whether a subscriber joining a publication stream receives as much data as is currently available, or receives only publications made from the time of the subscription.

  • None. A value of None causes the transmitter to transmit only publication made from the time of the subscription. This is the default value.
  • ALL. A value of ALL causes the transmitter to retransmit as much history of the topic as is known. In some circumstances, this can give a similar behavior to retained publications.
NSUBHIST
Monitor interval (milliseconds) How frequently, in seconds, that monitoring information is updated. If events messages are enabled, this parameter also controls how frequently event messages about the status of the Multicast handles created using this COMMINFO object are generated.

A value of 0 means that there is no monitoring. The default value is 60.

 MONINT
Communication events Controls whether event messages are generated for Multicast handles that are created using this COMMINFO object. Events will only be generated if they are enabled using the MONINT parameter. The three possible values are:

  • Disabled. Publications from applications not using Multicast are not bridged to applications that do use Multicast. This is the default value.
  • Enabled. Publications from applications not using Multicast are bridged to applications that do use Multicast.
  • Exception. Event messages are written if the message reliability is below the reliability threshold. The reliability threshold is set to 90.
COMMEV
Multicast bridge Controls whether publications from applications not using Multicast are bridged to applications using Multicast. Bridging does not apply to topics that are marked as MCAST(ONLY). As these topics can only be Multicast traffic, it is not applicable to bridge to the queue publish/subscribe domain. The two possible values are:

  • Disabled. Publications from applications not using Multicast are not bridged to applications that do use Multicast. This is the default for i5/OS.
  • Enabled. Publications from applications not using Multicast are bridged to applications that do use Multicast. This is the default for platforms other than i5/OS.
BRIDGE
Multicast heartbeat interval (milliseconds) The heartbeat interval is measured in milliseconds, and specifies the frequency at which the transmitter notifies any receivers that there is no further data available. The default value is 2000 milliseconds. MCHBINT
Multicast property control The multicast properties control how many of the MQMD properties and user properties flow with the message.

  • All. All user properties and all the fields of the MQMD are transported. This is the default value.
  • Reply. Only user properties, and MQMD fields that deal with replying to the messages, are transmitted. These properties are:

    • MsgType
    • MessageId
    • CorrelId
    • ReplyToQ
    • ReplyToQmgr
  • User. Only the user properties are transmitted.
  • None. No user properties or MQMD fields are transmitted.
  • Compatible. This value causes the transmission of the message to be done in a compatible mode to RMM. This allows some inter-operation with the current XMS applications and Broker RMM applications.
MCPROP


Statistics page

The following table lists the attributes that we can set on the Statistics page of the Communication Information properties dialog. The Statistics page displays information about the history of the communication information object. We cannot edit any of these attributes.

Attribute Meaning MQSC parameter
Alteration date Read-only. This is the date on which the communication information object's attributes were last altered. ALTDATE
Alteration time Read-only. This is the time at which the communication information object's attributes were last altered. ALTTIME