What does the Transmission Control Protocol (TCP) add to each segment's header?

The Transmission Control Protocol (TCP) adds sequence numbers to each segment's header to ensure that data is transmitted in the correct order. Sequence numbers play a crucial role in enabling reliable communication over the network. They allow the receiving side to identify the order of segments and reassemble them properly if they arrive out of sequence. This is essential for maintaining data integrity and ensuring that applications receive the information as intended.

Sequence numbers also facilitate error detection and recovery processes. If packets are lost during transmission, TCP can use the sequence numbers to request retransmission of specific segments, thus ensuring that the communication is reliable and complete.

While error-checking bits and IP addresses are also important components of data transmission, they serve different purposes. Error-checking bits are primarily used for detecting errors in the data payload, while IP addresses are relevant at the network layer for routing packets rather than at the transport layer where TCP operates. Transmission rate information is not part of the TCP header but is typically managed by higher-level protocols and flow control mechanisms.