F5CAB2 Exam Dumps - BIG-IP Administration Data Plane Concepts (F5CAB2) exam

In the F5 BIG-IP system, virtual servers are categorized based on their destination address and mask. The system distinguishes between three primary destination scopes:

Host Virtual Server: A virtual server that has a specific IP address (e.g., 10.10.10.50) and a /32 mask.

Network Virtual Server: A virtual server that has a destination address representing a subnet (e.g., 192.168.10.0) and a specific mask (e.g., /24).

Wildcard Virtual Server: A virtual server that has a destination address of 0.0.0.0 (or :: for IPv6) and a mask of 0.0.0.0 (or /0).

While a "Forwarding (IP)" virtual server (Option D) is the Type (behavioral configuration) often used to route traffic without load balancing, the term Wildcard (Option C) is the specific administrative term used to define the "type" of virtual server based on the 0.0.0.0 destination address.

A common architectural use case is to create a Wildcard Virtual Server that listens only on an internal VLAN to act as a default gateway for outbound traffic (Internet access) for back-end servers. This ensures the BIG-IP system can process and forward traffic that does not match any other specific virtual server configuration.

With Least Connections (member), BIG-IP attempts to send new connections to the pool member with the fewest current connections. In a perfectly “stateless” scenario (no affinity), this often trends toward a fairly even distribution over time.

However, persistence overrides load balancing:

When a persistence profile is applied, BIG-IP will continue sending a client (or client group) to the same pool member based on the persistence record (cookie / source address / SSL session ID, etc.).

This means even if another pool member has fewer connections, BIG-IP may still select the persisted member to honor session affinity.

The result can be uneven active connection counts, even though the configured load balancing method is Least Connections.

Why the other options are not the best cause:

A. Priority Group Activation is disabledPriority Group Activation only affects selection when priority groups are configured; disabling it does not inherently create uneven distribution under Least Connections.

B. SSL Profile Server is appliedA server-side SSL profile affects encryption to pool members, but it does not by itself cause skewed selection across pool members. (Skew could happen indirectly if members have different performance/latency, but that’s not the primary, expected exam answer.)

D. Incorrect load balancing methodLeast Connections is a valid method and does not itself explain unevenness unless something is overriding it (like persistence) or pool members are not all eligible.

Conclusion:

A persistence profile is the most common and expected reason that active connections become unevenly distributed, because persistence takes precedence over the Least Connections load-balancing decision.

In a BIG-IP high availability (HA) configuration, Auto-Sync is a device trust feature that automatically synchronizes configuration changes from the Active device to the Standby device within a Sync-Failover device group.

Key principles from BIG-IP Administration Data Plane Concepts:

The Active device is always the authoritative source of configuration

Configuration changes are intended to be made only on the Active device

With Auto-Sync enabled, any time the Active device configuration changes, the system automatically pushes the configuration to all Standby members of the device group

Configuration changes made directly on a Standby device are not preserved

In this scenario:

The administrator modifies a Virtual Server on the Standby device

That change is local only and does not alter the device group’s synchronized configuration

When Auto-Sync next runs (triggered by a change on the Active device or an internal sync event), the Active device configuration overwrites the Standby configuration

As a result, the configuration change made on the Standby device is undone.

Why the Other Options Are Incorrect:

A – The change is not undone only when another change is made; it is undone during the next Auto-Sync operation

B – Changes made on the Standby device are never propagated to the Active device

D – Auto-Sync does not merge or promote Standby changes into the HA pair configuration

Best Practice Reinforced:

Always perform configuration changes on the Active BIG-IP device when Auto-Sync is enabled to ensure consistent and predictable HA behavior.

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