156-315.81.20 Gateway Deployment and Upgrades Practice Question
A security administrator is deploying a new R81.20 Security Gateway in a high-traffic data center. The gateway has four physical interfaces: eth0 (management), eth1, eth2, and eth3 (all 10 Gbps). To optimize throughput and CPU utilization, the administrator wants to combine eth1, eth2, and eth3 into a single logical interface using 802.3ad Link Aggregation (LACP). After configuring the bond interface in Gaia, the administrator notices that traffic is not being distributed evenly across the member interfaces and overall throughput is lower than expected. Which of the following is the most likely cause?
⚠ Common exam trap
The trap here is assuming that configuring the bond on the gateway alone is sufficient, without verifying the switch-side LACP configuration.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The switch ports connected to eth1, eth2, and eth3 are not configured as an LACP port-channel.
The correct answer is that the switch ports must be configured as an LACP port-channel. Link Aggregation requires both ends to be configured for LACP; otherwise, the bond will not operate correctly, leading to uneven traffic distribution. The other options are either incorrect or less likely given the scenario. Ensuring proper LACP configuration on both the gateway and switch is essential for optimal throughput.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The gateway's CPU is not configured for multi-queue support, limiting the bond's throughput.
Why it's wrong here
While multi-queue support can improve performance, it is not required for basic LACP functionality. The scenario focuses on uneven traffic distribution across member interfaces, which points to a Layer 2/LACP negotiation issue rather than CPU queue configuration. Multi-queue is an optimization, not a prerequisite for even distribution.
- ✓
The switch ports connected to eth1, eth2, and eth3 are not configured as an LACP port-channel.
Why this is correct
For 802.3ad Link Aggregation to function, both the gateway and the switch must be configured for LACP. If the switch ports are not in an LACP port-channel, the bond will not form correctly, leading to uneven traffic distribution or failure. This is the most likely cause because the scenario implies the bond is configured on the gateway but does not mention switch configuration.
- ✗
The bond interface was configured with an IP address, but member interfaces should not have IP addresses.
Why it's wrong here
Member interfaces in a bond should not have IP addresses; only the bond interface should. If member interfaces had IP addresses, it could cause routing issues, but the scenario does not indicate that. This is not the most likely cause of uneven traffic distribution, as the primary issue is typically LACP negotiation with the switch.
- ✗
The bond interface was configured with a Layer 2 hash algorithm, but the network uses IP-based load balancing.
Why it's wrong here
A Layer 2 hash algorithm distributes traffic based on source and destination MAC addresses. In a typical data center with a router upstream, the MAC addresses remain constant, causing all traffic to hash to a single member. However, this is not the most likely cause because LACP typically uses Layer 3+4 hashing by default in Gaia, and the scenario does not specify the hash algorithm. The issue is more likely due to a missing configuration step.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Check Point exam blueprint
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