In BIG-IP architecture, link aggregation and redundancy at Layer 2 are implemented using Trunks , not virtual servers or pools.
According to BIG-IP Administration Data Plane Concepts:
Interfaces are the physical network ports on the BIG-IP device
A Trunk is a logical grouping of multiple interfaces
Trunks can be configured to use LACP (Link Aggregation Control Protocol) to:
Provide link redundancy
Increase aggregate bandwidth
Allow automatic detection of link failures
VLANs are then assigned to the trunk , not directly to individual interfaces, once aggregation is in place
Correct Design for the Scenario:
To connect BIG-IP to two upstream switches with LACP:
One physical interface from BIG-IP connects to Switch A
Another physical interface from BIG-IP connects to Switch B
Both interfaces are placed into the same trunk
LACP is enabled on the trunk and on the switches
This configuration allows:
Traffic to continue flowing if one interface or switch fails
Proper LACP negotiation between BIG-IP and the upstream switches
Clean separation of responsibilities (Layer 2 handled by trunking, Layer 4–7 by virtual servers)
Why Option D Is Correct:
A Trunk containing an interface connected to each switch is exactly how BIG-IP implements LACP-based interface binding
The trunk handles link state, load distribution, and failover at the data plane
Why the Other Options Are Incorrect:
A & B – Virtual servers operate at Layers 4–7 and have nothing to do with physical link aggregation or LACP
C – VLAN IDs and MAC addresses are not configured inside a trunk definition; trunks aggregate interfaces, and VLANs are applied to trunks
Key Data Plane Concept Reinforced:
On BIG-IP systems, LACP is always configured on a Trunk , which aggregates physical interfaces to provide Layer 2 resiliency and bandwidth aggregation . Virtual servers and pools are not involved in physical interface binding.
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