15.1 Introduction

TFTP is the Trivial File Transfer Protocol. It is intended to be used when bootstrapping diskless systems (normally workstations or X terminals). Unlike the File Transfer Protocol (FTP), which we describe in Chapter 27 and which uses TCP, TFTP was designed to use UDP, to make it simple and small. Implementations of TFTP (and its required UDP, IP, and a device driver) can fit in read-only memory.

This chapter provides an overview of TFTP because we'll encounter it in the next chapter with the Bootstrap Protocol. We also encountered TFTP in Figure 5.1 when we bootstrapped the host sun from the network. It issued a TFTP request after obtaining its IP address using RARP.

RFC 1350 [Sollins 1992] is the official specification of version 2 of TFTP. Chapter 12 of [Stevens 1990] provides a complete source code implementation of a TFTP client and server, and describes some of the programming techniques used with TFTP.