What is the primary function of TCP?

The primary function of TCP, or Transmission Control Protocol, is to ensure the reliable delivery of information across a network. It operates at the transport layer of the Internet Protocol Suite and is responsible for establishing a connection between two devices, ensuring that data packets are transmitted in the correct order, and managing retransmission of lost packets.

When data is sent over a network using TCP, it divides the data into smaller packets, sequences them, and adds error-checking information. This ensures that each packet can be verified upon arrival, and if any packets are missing or out of order, TCP will request that they be resent. This mechanism is crucial for applications where data integrity and order are essential, such as file transfers, web browsing, and streaming media.

The other options refer to different functions not specifically handled by TCP. For instance, encryption is typically managed by protocols like TLS/SSL, routing is the responsibility of protocols like IP, and user access management to websites is handled by application protocols such as HTTP/S. Therefore, TCP’s role in ensuring reliable delivery underscores its importance in network communications.