CLWLRANK channel attribute

The CLWLRANK channel attribute specifies the rank of channels for cluster workload distribution. The value must be in the range 0-9, where 0 is the lowest rank and 9 is the highest.

Use the CLWLRANK channel attribute if we want control over the final destination for messages sent to a queue manager in another cluster. Control the choice of final destination by setting the rank of the channels connecting a queue manager to the gateway queue managers at the intersection of the clusters.

When you set CLWLRANK, messages take a specified route through the interconnected clusters towards a higher ranked destination. For example, messages arrive at a gateway queue manager that can send them to either of two queue managers using channels ranked 1 and 2. They are automatically sent to the queue manager connected by a channel with the highest rank, in this case the channel to the queue manager ranked 2.

IBM MQ gets the rank of channels before checking channel status. Getting the rank before checking channel status means that even non-accessible channels are available for selection. It allows messages to be routed through the network even if the final destination is unavailable.

Notes:

• Specify this attribute on the cluster-receiver channel at the target queue manager. Any balancing you specify on the matching cluster-sender channel is likely to be ignored. See Cluster channels.
• If you also used the priority attribute CLWLPRTY, IBM MQ selects between available destinations. If a channel is not available to the destination with the highest rank, the message is held on the transmission queue. It is released when the channel becomes available. The message does not get sent to the next available destination in the rank order.

Parent topic: Workload balancing in clusters

Related concepts

• The cluster workload management algorithm

Related reference

• CLWLPRTY queue attribute
• CLWLRANK queue attribute
• CLWLUSEQ queue attribute
• CLWLUSEQ queue manager attribute
• CLWLMRUC queue manager attribute
• CLWLPRTY channel attribute
• CLWLWGHT channel attribute
• NETPRTY channel attribute