Measuring Network Throughput - Higher-level Protocols

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 — 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 (IP), defined by RFC 791. This imposes its own overheads.

Again, few systems simply copy the contents of files into IP packets, but use yet another protocol that manages the connection between two systems — TCP (Transmission Control Protocol), defined by RFC 1812. This adds its own overhead.

Finally, a final protocol layer manages the actual data transfer process. A commonly used protocol for this is the "file transfer protocol" (FTP), defined by RFC 959.