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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)                 9  TCP/IP General File Transfer Protocols (FTP and TFTP)                      9  Trivial File Transfer Protocol (TFTP)

TFTP Options and Option Negotiation 1 2 3 4 5 TCP/IP Electronic Mail System: Concepts and Protocols (RFC 822, MIME, SMTP, POP3, IMAP)

Read Request and Write Request Messages

These messages use a common message format, described in Table 235 and shown graphically in Figure 296.

Table 235: TFTP Read Request / Write Request Message Format

Field Name	Size (bytes)	Description
Opcode	2	Operation Code: Specifies the TFTP message type. A value of 1 indicates a Read Request message, while a value of 2 is a Write Request message.
Filename	Variable	Filename: The name of the file to be read or written.
Mode	Variable	Transfer Mode: The string “netascii” or “octet”, zero-terminated. (Why not just use one byte set to 0 for netascii and 1 for octet? Don't ask me! J)
Options	Variable

Figure 296: TFTP Read Request / Write Request Message Format

TFTP Options and Option Negotiation 1 2 3 4 5 TCP/IP Electronic Mail System: Concepts and Protocols (RFC 822, MIME, SMTP, POP3, IMAP)

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