DEFINE COMMINFO on Multiplatforms

Use the MQSC command DEFINE COMMINFO to define a new communication information object. These objects contain the definitions required for Multicast messaging.

Use MQSC commands

For information on how we use MQSC commands, see Performing local administration tasks using MQSC commands.

Syntax diagram
Parameter descriptions for DEFINE COMMINFO

Synonym: DEF COMMINFO

Values shown above the main line in the railroad diagram are the defaults supplied with IBM MQ, but your installation might have changed them. See Syntax diagrams.

DEFINE COMMINFO

Notes:

¹ Default for platforms other than IBM i.
² Default for IBM i.

Parameter descriptions for DEFINE COMMINFO

(comminfo name)

Name of the communications information object. This is required.

The name must not be the same as any other communications information object name currently defined on this queue manager. See Rules for naming IBM MQ objects.

TYPE

The type of the communications information object. The only type supported is 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's publish/subscribe domain.

DISABLED: Publications from applications not using Multicast are not bridged to applications that do use Multicast.
This is the default for IBM i.
ENABLED: Publications from applications not using Multicast are bridged to applications that do use Multicast. This is the default for platforms other than IBM i.

CCSID( integer )

The coded character set identifier that messages are transmitted on. Specify a value in the range 1 through 65535.

The CCSID must specify a value that is defined for use on the 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.

The default value is ASPUB which means that the coded character set is taken from the one that is supplied in the published message.

COMMEV

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.

DISABLED: Event messages are not generated for Multicast handles that are created using the COMMINFO object. This is the default value.
ENABLED: Event messages are generated for Multicast handles that are created using the COMMINFO object.
EXCEPTION: Event messages are written if the message reliability is below the reliability threshold The reliability threshold is set to 90 by default.

DESCR( string )

Plain-text comment. It provides descriptive information about the communication information object when an operator issues the DISPLAY COMMINFO command (see DISPLAY COMMINFO on Multiplatforms ).

It 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.

ENCODING

The encoding that the messages are transmitted in.

ASPUB: The encoding of the message is taken from the one that is supplied in the published message. This is the default value.
REVERSED
NORMAL
S390
TNS
encoding

GRPADDR

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. Using 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.

MCHBINT

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 value is in the range 0 to 999 999. The default value is 2000 milliseconds.

MCPROP

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.

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.

COMPAT

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.

XMS .NET Multicast messaging (using RMM) is deprecated from Version 9.2 and will be removed in a future release of XMS .NET.

MONINT( integer )

How frequently, in seconds, that monitoring information is updated. If events messages are enabled, this parameter also controls how frequently event messages are generated about the status of the Multicast handles created using this COMMINFO object.

A value of 0 means that there is no monitoring.

The default value is 60.

MSGHIST

This value is the amount of message history in kilobytes that is kept by the system to handle retransmissions in the case of NACKs (negative acknowledgments).

The value is in the range 0 to 999 999 999. A value of 0 gives the least level of reliability. The default value is 100.

NSUBHIST

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. Note: Using the value of ALL might have a detrimental effect on performance if there is a large topic history because all the topic history is retransmitted.

PORT( integer )

The port number to transmit on. The default port number is 1414.

LIKE( authinfo-name )

The name of a communication information object, with parameters that are used to model this definition.

If this field is not complete, and we do not complete the parameter fields related to the command, the values are taken from the default definition for an object of this type.

This default communication information object definition can be altered by the installation to the default values required.

REPLACE and NOREPLACE

Whether the existing definition is to be replaced with this one. This is optional. The default is NOREPLACE. Any object with a different disposition is not changed.

REPLACE: The definition replaces an existing definition of the same name. If a definition does not exist, one is created.
NOREPLACE: The definition does not replace an existing definition of the same name.

Parent topic: MQSC commands

Related information

Getting started with multicast