A load balancer is the best answer because it sits in the traffic path and distributes client requests across multiple backend servers. Since a load balancer tracks sessions, health checks, connection states, and response timers, incorrect timeout values or overloaded backend systems can cause client sessions to expire before the server responds. When that happens, packets or connections may be dropped, reset, or redirected, creating symptoms that appear as packet loss or failed application communication.

The CompTIA Network+ N10-009 objectives include availability concepts, load balancing, traffic management, and network performance troubleshooting. Load balancers are useful for improving scalability and fault tolerance, but they also introduce another decision point in the traffic path. If persistence, health checks, or timeout settings are misconfigured, application traffic can be interrupted.

An IDS is usually passive and monitors copied traffic, so it is less likely to directly cause packet loss. A CDN generally reduces latency and improves delivery by serving content closer to users. QoS is designed to prioritize important traffic and reduce delay, jitter, and packet loss for sensitive applications such as VoIP. Therefore, the most likely technology to increase packet loss due to timeout is a load balancer.