TCP stands for Transmission Control Protocol, which is a connection standard that specifies how different applications exchange information with each other. TCP, along with the Internet Protocol (IP), define how devices send data packets over the Internet.
TCP is in charge of establishing and maintaining the connection until the application programs have finished exchanging information. This includes everything from the initial opening of the connection to how the application data is broken into packets for delivery, and further steps, all the way up to the final acknowledgement received upon successful data transmission.
When the browser wants to fetch a resource from your server, it opens a TCP connection to send the HTTP request.
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