Listener ports running in non Application Server Facilities (non-ASF) mode

Listener ports running in non-ASF mode can be configured to monitor the queue destination and the topic destination using Server Sessions. Server sessions can have multiple conversations, the maximum number of which can be calculated in each case.

Listener ports can be configured to run in non-ASF mode which changes the way the listener ports monitor JMS destinations. Message-driven bean applications, using listener ports in non-ASF mode of operation, create a conversation for every server session used to run a message-driven bean instance to process messages. The listener port property maximum sessions specifies the maximum number of Server Sessions that can be active at any one time for a given listener port. The default value for this property is 10.

When running in non-ASF mode, a listener port monitoring a queue destination will automatically create the number of Server Sessions specified by the listener port property Maximum sessions. All of these Server Sessions make use of JMS Sessions taken from the session pool associated with the JMS Connection that the listener port is using, and continually monitor a JMS Destination for suitable messages.

If the listener port is configured to monitor a topic destination, the value of Maximum sessions is ignored and a single Server Session is used.

The Server Sessions used by a listener port running in non-ASF mode remain active until the listener port is stopped, at which point the JMS Sessions that were used are returned to the session pool Free Pool for the JMS Connection that the listener port was using.

For more information about how the session pool is used, and how the conversations between WebSphere Application Server and IBM MQ are managed, see JMS connection factories.

For more information about ASF and non-ASF mode of operation, and how to configure Listener Ports to use non-ASF mode, see the IBM Developer article When to use ASF and non-ASF modes to process messages in WebSphere Application Server.

Calculating the maximum number of conversations while monitoring a queue destination

The maximum number of conversations from a single listener port, running in non-ASF mode and monitoring a queue destination to IBM MQ can be calculated using the following formula:

Maximum number of conversations = Maximum sessions

The number of channel instances that will be created to allow this number of conversations to take place can be found by using the following calculation:

     Maximum number of channel instances =
        Maximum number of conversations / SHARECNV for the channel being used

Any remainder from this calculation can be rounded up. For a simple listener port running in non-ASF mode that is using the default value for the Maximum sessions property and monitoring a queue destination, the maximum number of conversations that can exist between WebSphere Application Server and IBM MQ for this listener port is:

Maximum number of conversations = Maximum sessions

For example:

     = 10

If this listener port is connecting to IBM MQ using a channel that has the SHARECNV property set to 10, then the number of channel instances that are created is calculated as:

     Maximum number of channel instances =
        Maximum number of conversations / SHARECNV for the channel being used

For example:

     = 10 / 10
     = 1

Calculating the maximum number of conversations while monitoring a topic destination

For a listener port running in non-ASF mode and configured to monitor a topic destination, the number of conversations from the listener port to IBM MQ is:

 Maximum number of conversations = 1

The number of channel instances that will be created to allow this number of conversations to take place can be found by using the following calculation:

     Maximum number of channel instances =
        Maximum number of conversations / SHARECNV for the channel being used

Any remainder from this calculation can be rounded up. For a simple listener port running in non-ASF mode that is using the default value for the Maximum sessions property and monitoring a topic destination, the maximum number of conversations that can exist between WebSphere Application Server and IBM MQ for this listener port is:

Maximum number of conversations = Maximum sessions

For example:

     = 10

If this listener port is connecting to IBM MQ using a channel that has the SHARECNV property set to 10, then the number of channel instances that are created is calculated as:

     Maximum number of channel instances =
        Maximum number of conversations / SHARECNV for the channel being used

For example:

     = 10 / 10
     = 1

Parent topic: Determining the number of TCP/IP connections that are created from WebSphere Application Server to IBM MQ