What is Trivial File Transfer Protocol (TFTP)

Trivial File Transfer Protocol


Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol, with the functionality of the basic form of FTP. TFTP is used to transfer files from remote computer such as diskless workstations. Disk-less workstation do not have their own storage disk and boot from a network host or server. The disk-less workstation when they startup, they are unable to read whole TCP/IP implementation from hard disk. The diskless workstation start with built software. It obtains the configuration information from a server and then downloads the rest of their software from another computer.

TFTP Communication between Client and Server


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Communication and messaging in TFTP is very different than it is in FTP because of the different transport layer protocol used by each such as stream data orientation (Send data byte by byte) and reliable delivery of data. TFTP makes used of the User Datagram protocol (UDP). UDP packages the data into individual message. The protocol information and the data are sent in different packets. TFTP must also take care of timing of the transmission to detect the lost datagrams and then re-transmitting the lost datagram packets as needed. TFTP perform send and receive operation, the TFTP servers allow connections from TFTP clients. A Separate TFTP server module is executed by many hosts that run FTP servers. By starting a TFTP client program, TFTP used initiates connections. the process of transferring a file consist of three main phases.

  1. Initial Connection – The TFTP client send an initial request to the server to establish the connection. The server sends the response to the client to open the connection.
  2. Data Transfer – After creating the connection, data transfer is initiated between the client and the server. They both exchange TFTP messages. The client sends data and the server sends acknowledgement vice versa.
  3. Connection Termination – The connection is terminated when the last TFTP message containing connection has been sent and acknowledged.

Trivial File Transfer Protocol

(Trivial File Transfer Protocol) TFTP uses the connection-less UDP for communication. In TFTP the client and server exchange TFTP messages. The UDP port number is 69 is reserved for TFTP. By using this Port. the TFTP server listen continuously request. A temporary port number is chosen by the client for its initial communication. This port number identifies the data transfer and called a TID (Transfer Identifier). The server selects a temporary TID to server response back to the client. The server does not port number 69. 

In TFTP communication, the client and server exchange data and acknowledgement message. Once device sends data messages and wait for acknowledgements, the other sends acknowledgement wait for data messages. This form of communication less efficient. As TFTP uses UDP there is no assume that the messages sent will reach at the destination. For the reliability, It uses timers to detect the lost transmission and resend them. The sending device will resend the message if it does not receive an acknowledgement reasonable period of time, and the process is same with the acknowledgement section. 

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Rakesh Kumar
Rakesh Kumar is a Network engineer and a Blogger. He is crazy for learn and write about Technology , Tech and Computer Tips and Tricks Blog.

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