TCP 3-way Handshake

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) both work in the transportation layer. TCP is a connection-oriented protocol, while UDP is considered as a connectionless protocol.

The connection-oriented feature for TCP is represented by the 3-way handshake procedure:

  1. When typing a URL in the web browser, the web browser will translate the request into a packet, with a SYN segment, and send it to the server.
  2. The server receives the packet, and replies with another packet with a SYN-ACK segment (ACK refers to Ackowledge).
  3. The web browser receives the SYN-ACK packet, and replies with a packet with an ACT segment. Hence the handshake completes and connection is built.