A load balancer is used to spread requests across multiple servers to optimize resource use, maximize throughput, reduce response time, and avoid overload on any single server. By distributing the load, the load balancer helps ensure that the web application remains highly available and reliable to users. While a jump server provides secure administrative access to servers from a single point, an intrusion detection system monitors network traffic for malicious activities, a firewall controls incoming and outgoing traffic based on security rules, and a proxy server acts as an intermediary for requests. None of these devices specifically distribute network traffic among multiple servers like a load balancer does.