TCP Segmentation

TCP is often called a "connection-oriented" protocol because it ensures the successful delivery of data to the receiving host. Figure 2-1 shows how the TCP protocol receives the stream from the rlogin command. TCP divides the data received from the application layer into segments and attaches a header to each segment.

Segment headers contain sender and recipient ports, segment ordering information, and a data field known as a checksum. The TCP protocols on both hosts use the checksum data to determine whether data has transferred without error.