Editing Measuring network throughput (section)

==Higher-level protocols==

Few systems transfer files and data by simply copying the contents of the file into the 'Data' field of HDLC or PPP frames &mdash; another protocol layer is used to format the data inside the 'Data' field of the HDLC or PPP frame. The most commonly used such protocol is [[Internet Protocol]]<nowiki> (IP), defined by RFC 791. This imposes its own overheads.</nowiki>

Again, few systems simply copy the contents of files into IP packets, but use yet another protocol that manages the connection between two systems &mdash; TCP ([[Transmission Control Protocol]]<nowiki>), defined by RFC 1812. This adds its own overhead.</nowiki>

Finally, a final protocol layer manages the actual data transfer process. A commonly used protocol for this is the "[[file transfer protocol]]<ref>Lydia Parziale, D. T. (2006). TCP/IP TUTORIAL AND TECHNICAL OVERVIEW</ref>