Which protocol is utilized for ensuring reliable delivery of data packets?

The protocol utilized for ensuring reliable delivery of data packets is TCP, or Transmission Control Protocol. TCP is designed to provide a reliable, ordered, and error-checked delivery of data between applications that communicate over a network. It accomplishes this through various mechanisms, such as acknowledgment packets, which confirm receipt of data, and retransmission of lost packets, ensuring that all data sent from the sender arrives correctly at the receiver.

Additionally, TCP establishes a connection between the client and server before any data transfer begins, which is a part of its reliable communication process. It also manages flow control and congestion control, which helps optimize the data transmission process and prevents network overloads.

Other protocols mentioned may serve different purposes, with UDP, for instance, focusing on speed and efficiency over reliability, as it does not provide mechanisms for acknowledgment of receipt, making it suitable for applications where speed is critical. FTP (File Transfer Protocol) is primarily used for transferring files and can operate over TCP for reliable delivery, while HTTP (Hypertext Transfer Protocol) is used for transferring web pages and relies on TCP for the underlying reliable communication. Therefore, TCP is the protocol specifically designed for ensuring reliable delivery of data packets.