What is TCP?

What is TCP? It stands for transmission control protocol and it is one of the main protocols used in the TCP/IP network. The transmission control protocol is responsible for establishing reliable communication between two computers in a network and ensures that the data is received correctly in the right order. TCP is also responsible for delivering data. If a data packet is not received by the receiver computer, it will resends the data packet to the receiver computer.

Without TCP, the data transmitted between two computers in a network may be missing data or will receive data in out of order. For example, if you do not use this protocol, you will load a web page with missing images, backward or out of order texts. Also, when you download a file, you might not receive the entire file, instead, you could get error messages such as “error in file downloading” or “incomplete download” etc.

3-way Handshake in TCP

Now that you know what is TCP, here’s a couple of interesting details about it. By being a connection-oriented protocol, it will first acknowledge a session between two computers that are trying to communicate with each other. Before any communication takes place, the two computers first verify and establish a connection between them using a mechanism called a 3-way handshake.

In a 3-way handshake, the sender computer sends a message to the receiver computer. Upon receiving the message, the receiver computer sends an acknowledgment message to the sender computer to confirm that it has received the first message. When the sender computer receives the acknowledgment message, it sends another message back to the receiver computer to establish the connectivity between the two computers. Once the connection is established, the two computers can communicate with each other.