Change, Copy, and Create Communication Information Object on Multiplatforms
The Change Communication Information Object command changes existing communication information object definitions. The Copy and Create Communication Information Object commands create new communication information object definitions - the Copy command uses attribute values of an existing communication information object definition.
The Change communication information (MQCMD_CHANGE_COMM_INFO) command changes the specified attributes of an existing IBM MQ communication information object definition. For any optional parameters that are omitted, the value does not change.
The Copy communication information (MQCMD_COPY_COMM_INFO) command creates an IBM MQ communication information object definition, using, for attributes not specified in the command, the attribute values of an existing communication information definition.
The Create communication information (MQCMD_CREATE_COMM_INFO) command creates an IBM MQ communication information object definition. Any attributes that are not defined explicitly are set to the default values on the destination queue manager.
Required parameter (Change communication information)
- ComminfoName (MQCFST)
- The name of the communication information definition to be changed (parameter identifier:
MQCA_COMM_INFO_NAME).
The maximum length of the string is MQ_COMM_INFO_NAME_LENGTH.
Required parameters (Copy communication information)
- FromComminfoName (MQCFST)
- The name of the communication information object definition to be copied from (parameter
identifier: MQCACF_FROM_COMM_INFO_NAME).
The maximum length of the string is MQ_COMM_INFO_NAME_LENGTH.
- ToComminfoName (MQCFST)
- The name of the communication information definition to copy to (parameter identifier:
MQCACF_TO_COMM_INFO_NAME).
The maximum length of the string is MQ_COMM_INFO_NAME_LENGTH.
Required parameters (Create communication information)
- ComminfoName (MQCFST)
- The name of the communication information definition to be created (parameter identifier:
MQCA_COMM_INFO_NAME).
The maximum length of the string is MQ_COMM_INFO_NAME_LENGTH.
Optional parameters (Change, Copy, and Create communication information)
- Bridge (MQCFIN)
- Controls whether publications from applications not using Multicast are bridged to applications
using multicast (parameter identifier: MQIA_MCAST_BRIDGE).
Bridging does not apply to topics that are marked as MCAST(ONLY). As these topics can only have multicast traffic, it is not applicable to bridge to the non-multicast publish/subscribe domain.
- MQMCB_DISABLED
- Publications from applications not using multicast are not bridged to applications that do use Multicast. This is the default for IBM i.
- MQMCB_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. This value is not valid on IBM i.
- CCSID (MQCFIN)
- The coded character set identifier that messages are transmitted on (parameter identifier:
MQIA_CODED_CHAR_SET_ID).
Specify a value in the range 1 to 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.
- CommEvent (MQCFIN)
- Controls whether event messages are generated for multicast handles that are created using this
COMMINFO object (parameter identifier: MQIA_COMM_EVENT).
Events are only generated if monitoring is also enabled using the MonitorInterval parameter.
- MQEVR_DISABLED
- Publications from applications not using multicast are not bridged to applications that do use multicast. This is the default value.
- MQEVR_ENABLED
- Publications from applications not using multicast are bridged to applications that do use multicast.
- MQEVR_EXCEPTION
- Event messages are written if the message reliability is below the reliability threshold The reliability threshold is set to 90 by default.
- Description (MQCFST)
- Plain-text comment that provides descriptive information about the communication information
object (parameter identifier: MQCA_COMM_INFO_DESC).
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).
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.
The maximum length is MQ_COMM_INFO_DESC_LENGTH.
- Encoding (MQCFIN)
- The encoding that the messages are transmitted in (parameter identifier: MQIACF_ENCODING).
- MQENC_AS_PUBLISHED
- The encoding of the message is taken from the one that is supplied in the published message. This is the default value.
- MQENC_NORMAL
- MQENC_REVERSED
- MQENC_S390
- MQENC_TNS
- GrpAddress (MQCFST)
- The group IP address or DNS name (parameter identifier: MQCACH_GROUP_ADDRESS).
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.
The maximum length is MQ_GROUP_ADDRESS_LENGTH.
- MonitorInterval (MQCFIN)
- How frequently monitoring information is updated and event messages are generated (parameter
identifier: MQIA_MONITOR_INTERVAL).
The value is specified as a number of seconds in the range 0 to 999 999. A value of 0 indicates that no monitoring is required.
If a non-zero value is specified, monitoring is enabled. Monitoring information is updated and event messages (if enabled using CommEvent, are generated about the status of the multicast handles created using this communication information object.
- MsgHistory (MQCFIN)
- This value is the amount of message history in kilobytes that is kept by the system to handle
retransmissions in the case of NACKs (parameter identifier: MQIACH_MSG_HISTORY).
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.
- MulticastHeartbeat (MQCFIN)
- 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 (parameter identifier:
MQIACH_MC_HB_INTERVAL).
The value is in the range 0 to 999 999. The default value is 2000 milliseconds.
- MulticastPropControl (MQCFIN)
- The multicast properties control how many of the MQMD properties and user properties flow with
the message (parameter identifier: MQIACH_MULTICAST_PROPERTIES).
- MQMCP_ALL
- All user properties and all the fields of the MQMD are transported. This is the default value.
- MQMCP_REPLY
- Only user properties, and MQMD fields that deal with replying to the messages, are transmitted.
These properties are:
- MsgType
- MessageId
- CorrelId
- ReplyToQ
- ReplyToQmgr
- MQMCP_USER
- Only the user properties are transmitted.
- MQMCP_NONE
- No user properties or MQMD fields are transmitted.
- MQMCP_COMPAT
- Properties are transmitted in a format compatible with previous MQ multicast clients.
- NewSubHistory (MQCFIN)
- 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 (parameter identifier: MQIACH_NEW_SUBSCRIBER_HISTORY).
- MQNSH_NONE
- A value of NONE causes the transmitter to transmit only publication made from the time of the subscription. This is the default value.
- MQNSH_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.
Use the value of MQNSH_ALL might have a detrimental effect on performance if there is a large topic history because all the topic history is retransmitted.
- PortNumber (MQCFIN)
- The port number to transmit on (parameter identifier: MQIACH_PORT).
The default port number is 1414.
- Type (MQCFIN)
- The type of the communications information object (parameter identifier: MQIA_COMM_INFO_TYPE).
The only type supported is MQCIT_MULTICAST.
Parent topic: Definitions of the Programmable Command Formats