Configure the .ini files for Multicast

Use this information to understand the IBM MQ Multicast fields in the .ini files.

Additional IBM MQ Multicast configuration can be made in an ini file. The specific ini file that you must use is dependent on the type of applications:

• Client: Configure the MQ_DATA_PATH /mqclient.ini file.
• Queue manager: Configure the MQ_DATA_PATH /qmgrs/QMNAME/qm.ini file.

where MQ_DATA_PATH is the location of the IBM MQ data directory ( /var/mqm/mqclient.ini ), and QMNAME is the name of the queue manager to which the .ini file applies.

The .ini file contains fields used to fine-tune the behavior of IBM MQ Multicast:

Multicast:
Protocol       = IP | UDP
IPVersion       = IPv4 | IPv6 | ANY | BOTH
LimitTransRate    = DISABLED | STATIC | DYNAMIC
TransRateLimit    = 100000
SocketTTL       = 1
Batch         = NO
Loop         = 1
Interface       = <IPaddress>
FeedbackMode     = ACK | NACK | WAIT1
HeartbeatTimeout   = 20000
HeartbeatInterval   = 2000

Protocol

UDP

In this mode, packets are sent using the UDP protocol. Network elements cannot provide assistance in the multicast distribution as they do in IP mode however. The packet format remains compatible with PGM. This is the default value.

IP

In this mode, the transmitter sends raw IP packets. Network elements with PGM support assist in the reliable multicast packet distribution. This mode is fully compatible with the PGM standard.

IPVersion

IPv4

Communicate using the IPv4 protocol only. This is the default value.

IPv6

Communicate using the IPv6 protocol only.

ANY

Communicate using IPv4, IPv6, or both, depending on which protocol is available.

BOTH

Supports communication using both IPv4 and IPv6.

LimitTransRate

DISABLED

There is no transmission rate control. This is the default value.

STATIC

Implements static transmission rate control. The transmitter would not transmit at a rate exceeding the rate specified by the TransRateLimit parameter.

DYNAMIC

The transmitter adapts its transmission rate according to the feedback it gets from the receivers. In this case the transmission rate limit cannot be more than the value specified by the TransRateLimit parameter. The transmitter tries to reach an optimal transmission rate.

TransRateLimit

The transmission rate limit in Kbps.

SocketTTL

The value of SocketTTL determines if the multicast traffic can pass through a router, or the number of routers it can pass through.

Batch

Controls whether messages are batched or sent immediately There are 2 possible values:

• NO The messages are not batched, they are sent immediately.
• YES The messages are batched.

Loop

Set the value to 1 to enable multicast loop. Multicast loop defines whether the data sent is looped back to the host or not.

Interface

The IP address of the interface on which multicast traffic flows. For more information and troubleshooting, see: Testing multicast applications on a non-multicast network and Set the appropriate network for multicast traffic

FeedbackMode

NACK

Feedback by negative acknowledgments. This is the default value.

ACK

Feedback by positive acknowledgments.

WAIT1

Feedback by positive acknowledgments where the transmitter waits for only 1 ACK from any of the receivers.

HeartbeatTimeout

The heartbeat timeout in milliseconds. A value of 0 indicates that the heartbeat timeout events are not raised by the receiver or receivers of the topic. The default value is 20000.

HeartbeatInterval

The heartbeat interval in milliseconds. A value of 0 indicates that no heartbeats are sent. The heartbeat interval must be considerably smaller than the HeartbeatTimeout value to avoid false heartbeat timeout events. The default value is 2000.