TCP/IP (Transmission Control Protocol/Internet Protocol) is the suite of protocols used to transmit data over the internet and other networks that use IP.
It is the foundation of the internet, and it is responsible for how data is transmitted, routed, and received by devices on the network.
- When a user types a web address (URL) into their web browser, the browser generates an HTTP (Hypertext Transfer Protocol) request for the web page. This request is sent to the IP address associated with the domain name of the website.
- The request first goes to the client's computer's network interface card (NIC) and then to the data link layer, where the NIC's hardware address is added to the packet as the source address. Then the packet is sent to the network layer, where it gets the IP address of the destination machine.
- At the network layer, the IP protocol is responsible for routing the packet to the destination IP address. Routers on the network determine the best path for the packet to take, based on the destination IP address, and send the packet on its way.
- Once the packet reaches the destination server, the server's NIC receives the packet, and the data link layer removes the hardware address. The network layer then passes the packet to the transport layer, where the TCP protocol is responsible for ensuring that the data is received correctly and in the right order.
- The transport layer then sends the packet to the application layer, where the HTTP protocol is used to interpret the request, and an HTTP response is generated. This response is sent back to the client, following the same path in the reverse direction, and the browser interprets it to display the webpage to the user.
It's important to note that in addition to the steps described above, other protocols and technologies are also used to secure the connection, such as HTTPS, SSL, and TLS, to encrypt the data being sent and received, to authenticate the server and client, and to prevent eavesdropping.