A repeater is a network device that operates at the physical layer of the OSI model and is used to regenerate or amplify an incoming signal before retransmitting it. Its primary function is to extend the distance of a network by increasing the strength and quality of signals over long distances or through dense blocks. Repeaters are often used in LANs and WANs to improve the performance and reliability of the network. They can help prevent data loss, reduce errors, and ensure that the signal arrives at its intended destination with sufficient strength and quality. Repeaters can be classified into two categories based on the types of signals they regenerate: analog repeaters and digital repeaters. They can also be categorized based on the types of networks they connect: wired repeaters and wireless repeaters. Repeaters are simple to install, cost-effective, and do not require any processing overhead. Some advantages of repeaters include their ability to extend the length or coverage area of networks and their ability to amplify attenuated signals and reconstruct signals distorted by transmission loss.