Which statement best describes the role of TCP in network communications?

The statement that TCP ensures reliable data transmission accurately captures the primary function of the Transmission Control Protocol. TCP is designed to provide a reliable, ordered, and error-checked delivery of data between applications running on hosts communicating over an IP network. It achieves this by establishing a connection-oriented communication session before data transfer begins, ensuring that all packets are delivered accurately and in the correct sequence.

TCP incorporates various mechanisms such as error detection, correction, and retransmission of lost packets, which enhance its reliability. Each data segment sent is acknowledged by the receiving end, and if an acknowledgment isn't received within a specified timeframe, TCP retransmits the data. This makes TCP especially important for applications where data integrity and order are critical, such as web browsing, file transfers, and email.

Other statements do not reflect the core functions of TCP. For example, TCP does not exclusively focus on establishing secure connections; that role is typically fulfilled by protocols like TLS or SSL, which can work in conjunction with TCP. Additionally, TCP does not handle routing or address assignment; these tasks are managed by the Internet Protocol (IP). Lastly, while domains and their connectivity rely on multiple protocols and systems, TCP's primary function is not to manage the connection between different internet domains. Instead, it