Unicast communication

Cluster Aware AIX® (CAA) uses multicast communications for heartbeat and other protocol messages, which might require an additional network setup at customer site. The unicast cluster provides a new capability to CAA to support clustering with simultaneous unicasting of CAA protocol messages, instead of multicasting. It is applied to all sites within the CAA cluster.

The communication mode of the cluster can be toggled at run time by using the clctrl -tune command and changing the value of the communication_mode tunable parameter, between u (for unicast) and m (for multicast). The CAA default value is m but it can vary depending on product. For example, VIOS SSP defaults to the unicast mode.