In this illustration we see a desktop computer labeled Host A, and a server labeled Host B positioned side-by-side. Each host has a dotted line extending vertically downward, representing the passage of time. A series of blue arrows extending from one side to the other represents the steps of communication in a TCP connection.

The connection begins at the topmost point on Host A's timeline. A blue arrow extends diagonally downward to the right to Host B's timeline. This arrow is labeled "one segment." A blue arrow extends from this point on Host B's timeline diagonally downward to Host A's timeline. The area on Host A's timeline between the two arrows is labeled as "RTT." At this point on Host A's timeline, two arrows extend diagonally downward to Host B's timeline. These are labeled "two segments." Two arrows extend from Host B's timeline back to Host A's timeline. In response, four arrows extend from Host A to Host B. These are labeled "four segments." In response, four arrows extend from Host B back to Host A.