Which TCP protocol ensures the reliable transmission of data packets across a network?

The Transmission Control Protocol (TCP) is responsible for ensuring reliable transmission of data packets across a network. It achieves this reliability through a variety of mechanisms, such as establishing a connection-oriented session between the sender and receiver through a process known as three-way handshake. This process confirms that both ends are ready for communication and helps prevent data loss.

TCP provides error-checking and guarantees data delivery by implementing methods such as acknowledgment packets. When a data packet is sent, the receiver must acknowledge receipt; if the sender does not receive this acknowledgment within a specific timeframe, it will retransmit the packet. Additionally, TCP manages flow control and congestion control, which allows it to adapt the rate of data transmission based on the current network conditions and the receiver's capability to process the data.

In contrast, other protocols mentioned, such as User Datagram Protocol (UDP), HTTP, and FTP, do not inherently provide the same level of reliability as TCP. UDP, for instance, is a connectionless protocol that sends packets without establishing a reliable connection, making it faster but prone to potential packet loss. HTTP is an application layer protocol that depends on TCP for reliable data transmission, and FTP, while capable of reliable transfers, is built on top of TCP rather than being responsible for reliability