In this illustration, a desktop computer labeled "Client host" and a server labeled "Server host" are positioned side-by-side. Each has a dotted line extending vertically below it, representing the passage of time. The interaction between them begins at the topmost portion of the client host's timeline, at a point labeled "Connection request." A blue arrow, labeled "SYN=1, seq=client_isn," extends diagonally downward and to the right, where it intersects with the server host's timeline at a point labeled "Connection granted." An arrow labeled "SYN=1, seq=server_isn, ack=client_isn+1" extends diagonally leftward and intersects with the client host's timeline, at a point labeled "ACK." An arrow labeled "SYN=0, seq=client_isn+1, ack=server_isn+1" extends diagonally rightward and intersects with the server host's timeline.