EFTP
EFTP is a very simple, basic file transfer protocol, a data network application (the name notwithstanding) used to transfer files to or from a server host system, in the PUP protocol suite.
Unlike many current protocols, it is not run over a reliable byte stream protocol; instead, it is built directly on the un-reliable datagram service provided by PUP. EFTP includes its own acknowledgements, timeouts, and re-transmissions, and uses the checksums and sequence numbers provided by the underlying PUP layer.
This approach is a result of its creation in the very early stage of data networking work, when many computers were simpler, and reliable byte stream protocol were often not available in them; EFTP provides file transfer functionality from a small amount of code, suitable for uses such as bootstrapping a machine with no secondary storage over the network.
