Network diagram for TCP

About this network diagram for TCP

The TCP communication starts when a client decides to connect reliably with a server. The client sends a segment with a SYN flag. This flag requests synchronization of sequence numbers. This segment travels across the network and reaches the server. When the server gets the SYN request, it allocates resources and logs the attempt.

It then sends a SYN-ACK message. This reply confirms the client's sequence number. The server is ready when the client receives the SYN-ACK. The client then sends a final ACK message. After this, both sides have the same sequence numbers. The connection is fully established.

After the handshake, the client sends data segments. Each segment includes a sequence number. This number helps the receiver order the data. The server responds with acknowledgment numbers. These numbers show how much data it received.

This exchange goes on as both sides send and confirm data. If a segment is lost, duplicated, or out of order, TCP finds the problem. It requests missing segments again, ensuring reliable delivery. TCP adjusts its transmission speed using congestion control as data flows. It changes its sending window based on how quickly it receives acknowledgments.

During the session, the client and server hold buffers, timers, and state info. This helps them track progress. When communication ends, either side can start the connection termination sequence. This process makes sure all data is delivered before releasing resources. TCP clearly handles state transitions. It moves from connection setup to data transfer and then to closure. This ensures a controlled and reliable communication channel between endpoints.