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intermediate systems | internet protocol stack | data transmission | network vs transport layer | encapsulation |

Data Transmission

HyperText Transfer Protocol (HTTP), the Web's application-layer protocol uses TCP for reliable data transfer. Thus, a TCP connection must be established and maintained between client and server.

This application shows how a Web-Client initiates TCP connection establishment which involves a 3-way handshake. After completing the first two parts of the handshake, the client sends the HTTP request message combined with the third part (ACK message) of the 3-way handshake.

HTTP uses persistent connections in its default mode. The server leaves the TCP connection open after sending a response. Therefore subsequent requests between the same client and server can be sent over the same TCP connection.