SSH is a TCP Layer 4 protocol. Applying an HTTP profile causes BIG-IP to expect HTTP headers, breaking SSH sessions. Removing the HTTP profile allows raw TCP forwarding.

The two load balancing methods that consider all connections between the BIG-IP and each backend node — not just connections to a specific pool member — are Least Connections (node) and Weighted Least Connections (node) .

The critical distinction here lies in the node-level scope of evaluation. A node represents the backend server ' s IP address, regardless of how many services or ports it may be serving. Therefore:

Least Connections (node) directs new connections to the node with the fewest total active connections across all services on that server, providing a holistic connection-count perspective.

Weighted Least Connections (node) operates identically but factors in an administrator-defined ratio weight, allowing servers with greater capacity to proportionally absorb more connections while still evaluating total node-level connection counts.

By contrast:

Ratio (member) distributes traffic based on a static weight ratio and does not dynamically evaluate current connection counts.

Round Robin distributes traffic sequentially in rotation, completely ignoring current connection states on any node or member.

The node-based methods are particularly valuable in environments where a single backend server hosts multiple pool members across different ports, ensuring the server ' s overall load — not just per-service load — governs balancing decisions.

The requirement states that load balancing decisions must be based on the number of active connections on each pool member. This directly maps to the Least Connections (member) load balancing method.

According to the BIG-IP Administration: Data Plane Configuration documentation:

Least Connections (member) selects the pool member with the fewest active connections at the time of the request.

This method dynamically adapts to real-time traffic patterns and ensures that more heavily loaded pool members receive fewer new connections.

It is especially effective for web servers where connection duration may vary and equal distribution of active sessions is desired.

Why the other options are incorrect:

B. Round RobinDistributes connections sequentially without considering current load or active connections.

C. Ratio (member)Distributes traffic based on static ratios, not real-time connection counts.

D. Ratio (node)Uses predefined ratios at the node level and does not account for active connection counts.

Correct Resolution:

Using Least Connections (member) ensures that new connections are directed to the pool member currently handling the fewest active connections, meeting the stated requirement.

The configuration provided utilizes Priority Group Activation in conjunction with the min_active_members setting. Priority groups allow an administrator to define primary servers and " backup " servers within the same pool. The BIG-IP prioritizes traffic based on the assigned priority number, with the highest number receiving traffic first.

In this specific configuration, the priority 3 group is the primary group. Therefore, connections are first distributed to all pool members with priority 3 as long as they are available. The system will continue to use only the priority 3 group unless the number of available members in that group falls below the min_active_members value, which is set to 2.

If the priority 3 group has fewer than two active members, the BIG-IP " activates " the next available priority group (priority 2) and distributes traffic among the remaining members of priority 3 and all members of priority 2. This cascading logic continues down the list. Consequently, if both the priority 3 group and the priority 2 group have fewer than two members available, traffic is directed to the priority 1 group. This ensures that even in a multi-server failure scenario, the system has a last-resort group of servers to handle the traffic.

Option D is incorrect because if only one member of priority 3 goes down, there are still two members active (10.12.10.8 and 10.12.10.9). Since 2 is not less than the min_active_members threshold of 2, the priority 2 group will not yet be activated. Option B is incorrect because traffic flows from high priority to low priority, not the other way around.