TCP/IP Guide

TFTP Detailed Operation and Messaging

You saw earlier that TFTP operation consists of three general steps: initial connection, data transfer, and connection termination. All operations are performed through the exchange of specific TFTP messages. Let's take a more detailed look now at these three phases of operation and the specifics of TFTP messaging.

Initial Message Exchange

The first message sent by the client to initiate TFTP is either a read request (RRQ) message or a write request (WRQ) message. This message serves implicitly to establish the logical TFTP connection and to indicate whether the file is to be sent from the server to the client (read request) or the client to the server (write request). The message also specifies the type of ...