Refer to the exhibit.

BIG-IP Priority Group Activation causes members in the highest-numbered priority group to receive traffic first. F5 defines the activation value as the minimum number of available members required before traffic can remain confined to the higher-priority group. If availability falls below that threshold, the system activates the next lower priority group.

Here, Priority Group 3 is the highest group. Of its three members, only 172.16.15.7:80 is available. Because one available member is less than the configured threshold of 2 , BIG-IP must activate Priority Group 2 as well.

In Priority Group 2, only 172.16.15.4:80 is available. Adding this member provides two available members across the currently activated priority groups: 172.16.15.7:80 and 172.16.15.4:80. The required availability threshold is therefore satisfied, so Priority Group 1 does not need to participate. F5 specifically documents that traffic expands into lower-priority groups when the required number of members is unavailable in the higher-priority set.

Because the configured load-balancing method is Round Robin , new connections are distributed across these two eligible members.

Study Guide References/Topics: Pools; Priority-Based Member Activation; Priority Groups; Pool Member Availability; Round Robin Load Balancing.