What is the primary function of Internet Protocol (IP) in a network?

• A. Routes messages between computers on a network
• B. Encrypts data during transmission
• C. Establishes user authentication
• D. Provides physical medium for transmission

Answer: (A)

IP's primary function is to route messages between computers on a network. It provides logical addressing with IP addresses, so each packet carries a source and destination. Routers read these addresses and forward packets toward their destination, using routing tables and network topology to decide the best path. This enables devices across different networks to communicate, including across the Internet, even though the data may pass through many intermediate devices. IP operates at the network layer and delivers best-effort, connectionless delivery—no guaranteed delivery, order, or security is built in.

Encryption, authentication, and the physical transmission medium are handled by other mechanisms or layers. Encryption is provided by protocols like TLS or IPsec, authentication by separate services or protocols, and the physical medium by the underlying hardware and data-link/physical layers.