The Transmission Control Protocol (TCP) is crucial to the Internet's operation. It ensures that data sent between applications over a network is delivered reliably, in the right order, and without errors. One important aspect of TCP is its three-way handshake, which sets up a connection between a client and a server before any data is actually sent.

Today we will explore how the TCP Handshake is performed.

What is the TCP Handshake?

The TCP handshake is a simple three-step process that helps set up a reliable connection between two devices on a network. It ensures that both the client and the server are ready to chat and agree on key details, like the sequence numbers for sending data.

The Process

The three-way handshake is performed in the following way.

1. To begin the communication, the client node sends a SYN packet containing a connection request to the server.

2. If the receiving node (server) is listening on the port, The receiving node responds with a SYN-ACK, confirming that it has heard the requesting node.

3. The client node returns an ACK packet to the server, to let them know that, the nodes are good to send each other information.

Now, the connection is established and the data can be transmitted through the network.

Visual Representation

Consider the following figure to understand the three-way handshake.

Conclusion

The TCP three-way handshake is a key part of making sure communication is reliable in today's networks. This concept is very important for DevOps and Network Engineers to design or troubleshoot a network system. Learning his process is also important for Software Engineers.