What does TCP compute and compare to ensure data integrity?

The Transmission Control Protocol (TCP) computes and compares checksum values for ensuring data integrity. When TCP transmits data, it generates a checksum based on the contents of the TCP segment. This checksum is a form of redundancy check that allows the receiving end to verify that the data has not been altered during transmission.

When the receiver gets a TCP segment, it calculates the checksum for the received data and compares it with the checksum sent by the sender. If the two checksums match, it indicates that the data has likely maintained its integrity during transit. Conversely, if there is a discrepancy, the data may have been corrupted, which typically results in a request for retransmission.

The other options, while relevant to different aspects of networking and data transmission, do not directly pertain to the integrity of data as assessed by TCP. For instance, packet sizes deal with how large data packets are but do not confirm the accurate transmission of the content itself. Data types pertain to the format and categorization of data rather than its accuracy during transfer, and transmission speeds relate to how quickly data moves across the network but do not affect whether the data is received intact. Thus, checksum values are fundamental to the process of error-checking in TCP, making them the correct