15.5 Summary

TFTP is a simple protocol designed to fit into read-only memory and be used only during the bootstrap process of diskless systems. It uses only a few message formats and a stop-and-wait protocol.

To allow multiple clients to bootstrap at the same time, a TFTP server needs to provide some form of concurrency. Because UDP does not provide a unique connection between a client and server (as does TCP), the TFTP server provides concurrency by creating a new UDP port for each client. This allows different client input datagrams to be demultiplexed by the server's UDP module, based on destination port numbers , instead of doing this in the server itself.

The TFTP protocol provides no security features. Most implementations count on the system administrator of the TFTP server to restrict any client's access to the files necessary for bootstrapping only.

Chapter 27 covers the File Transfer Protocol (FTP), which is designed for general purpose, high-throughput file transfer.