Assignment 2
The Trivial File Transfer Protocol (TFTP) is an Internet software utility for transferring files
that is simpler to use than the File Transfer Protocol (FTP) but less capable. It is used
where user authentication and directo
ry visibility are not required. For example, it is used by Cisco routers and switches to
transfer images of the operating system from/to the devices.
NOTE: TFTP’s port is 69 (a system/OS port). This is below 1024 and therefore you
cannot bind a Socket to it unless you have administrative access rights on the machine
you are working. To avoid any complications you can use any port > 1024 to bind server
sockets.
Task 1: Implementation of the Trivial File Transfer
Protocol (TFTP)
For this task you need to implement (in Java) the Trivial File Transfer Protocol (TFTP) as
specified in RFC 1350. You will submit source code for a client and server application
that ‘speak’ the TFTP protocol. You will built your protocol on top of UDP. Compared to
the specifications in the RFC, you will implement a slightly simplified version:
• Support for octet mode only. The files should be transferred as a raw sequence of
bytes. Do not read, write or transfer files as characters.
• Support only for error handling when the server is unable to satisfy the request
because the file cannot be found.
• No support for error handling when data duplication occurs.
The client and server applications should be simple Java console applications. The
server should operate (i.e. read and write files) in the directory where it is started from.
The server should support simultaneous file transfers to and from multiple clients. The
client should just read command line arguments (or have a very simple console-based
menu – e.g. “press 1 to store file, press 2 to retrieve file”) and execute user commands
(i.e. reading or writing a file).
Hint: the simplest way to implement timeouts is by calling the setSoTimeout() method on
the DatagramSocket objects (assuming that you are using blocking I/O). If the timeout
expires, a java.net.SocketTimeoutException is raised, though the DatagramSocket is still
valid.
https://www.ietf.org/rfc/rfc1350.txt
Task 2: Implementation of an even simpler version
of TFTP on top of TCP
For this task you will use TCP sockets to implement a protocol that operates like TFTP
(i.e. supports only read and write operations). Given that TCP supports in-order, reliable
data transport, you should not implement the relevant mechanisms described in RFC
1350 (ACKs, retransmissions). The client and server applications should be equally
simple, as in Task 1. The server must be able to handle multiple file transfers.