Final answer:
A Load balancer is the solution associated with a device used to shift a load from one device to another, which improves efficiency and reliability of services.
Step-by-step explanation:
The solution that can be implemented as a software or hardware solution and is usually associated with a device -- such as a router, a firewall, or a Network Address Translation (NAT) system -- used to shift a load from one device to another is known as a Load balancer. A load balancer distributes network or application traffic across a number of servers. This improves the efficiency, reliability, and scalability of applications, websites, databases, and other services by ensuring that no single server carries too much of the load. In contrast, a Proxy serves as an intermediary for requests from clients seeking resources from other servers. A Hub is a basic networking device that connects multiple devices together, while a Switch connects devices and manages node-to-node communication within a network, ensuring that packets of data go to the correct destination.
For example, in a web application, a load balancer can distribute user requests across multiple web servers, allowing the system to handle more concurrent users and deliver a better user experience. It can also perform health checks on servers and automatically redirect traffic from failed servers to healthy ones.
Load balancers can be implemented at different levels of the network stack, such as application, transport, or network layer. They use various algorithms to determine how to distribute the traffic, including round-robin, least connection, and IP hashing.