Subnetting is a method used in computer networking to divide a larger network into smaller, more manageable sections called subnets. This process helps improve network performance and security by limiting broadcast traffic and isolating network issues. Each subnet can have its own set of IP addresses, making it easier to organize and manage devices within a network. By using subnet masks, network administrators can determine which portion of an IP address identifies the network and which part identifies the specific device. This allows for efficient use of IP addresses and helps in optimizing the overall network structure, ensuring that data flows smoothly between devices.