A subnetwork, often referred to as a subnet, is a smaller network within a larger network. It allows for better organization and management of IP addresses, improving network performance and security. By dividing a larger network into subnets, administrators can control traffic flow and isolate issues more effectively. Subnetworking is commonly used in Internet Protocol (IP) networks, where each subnet can have its own range of IP addresses. This division helps in optimizing resource usage and enhances security by limiting access to certain parts of the network. Subnetting is essential for efficient network design and operation.