NOCHANGE, PUSH, TRUST

All of these flags are set only by the load balancer. Whether they appear or not depends upon whether the particular load balancer implementation supports them, and if they are configured in the load balancer. The z/OS® administrator has no control over the settings of these flags.

The NOCHANGE flag can affect the amount of data transferred between the load balancer and the Advisor. If this flag is set, only data that has changed since the last time data was sent to the load balancer is included. Consult the load balancer documentation to determine whether this setting is supported.

The PUSH flag can have an effect on how soon the load balancer is informed of certain events. If the PUSH flag is not on, the load balancer must poll the Advisor periodically for updates. If this flag is on, certain events can be communicated to the load balancer earlier than would be possible if polling were in effect. Those events include quicker notification of a target application being taken out of service, and quicker notification of when the member's IP address has been moved to another system in the sysplex (VIPA takeover) or removed entirely. When the PUSH flag is on, the Advisor also sends the load balancer updated information about weights and status at least every update interval, if new information is available. Consult the load balancer documentation to determine whether this setting is supported.

The TRUST flag indicates that the load balancer allows other system components besides itself to register members with the load balancer. The z/OS Load Balancing Advisor does not currently exploit this feature.

Line 5 of Figure 1 shows all of these flags. For more information on the NOCHANGE, PUSH, and TRUST flags, see z/OS Communications Server: IP System Administrator's Commands.