---

The purpose of this project

This project demonstrates two file transfer protocols:

• Reliable file transfer (RFT) with positive acknowledgement in the absence of errors
• Reliable file transfer (RFT) with positive acknowledgement and retransmission – an example of a PAR protocol

The RFT application comprises client and server applications. The server (rft_server) has to be ran in one terminal window and the client (rft_client) in another terminal window either on the same host (in which case the server address will be 127.0.0.1) or a different host (in which case the server address will be for an external IP interface).

---

Ways to run the project

The following two shell scripts are provided as convenient ways to run the applications:

• run-server.sh to compile and run the rft_server (which also compiles the rft_client)

• run-client.sh to compile and run the rft-client

By default, the run-server.sh script will compile the applications and start the server on port 20333, and the run-client.sh script will start the client and attempt to send the file in660.txt to the server for output on the server side in the file ./out/out.txt. The normal transfer protocol is used by default.

That is, if you do:

./run-server.sh 

in one terminal window, and:

./run-client.sh

in another terminal window on the same host, then the client will transfer the file in660.txt to the server using the send_file_normal function.

Both scripts have options to allow you to specify a different port and/or server address and to transfer different files using either the normal transfer protocol without retransmission or the protocol with timeout and retransmission.

To see the server script help and usage message, enter the command:

./run-server.sh -h

To see the client script help and usage message, enter the command:

./run-client.sh -h

Also, you do not have to use the shell scripts. You can run the rft applications directly. To do this, to build the application enter the command:

make 

Then, assuming compilation succeeds, enter the command:

./rft_server 

to see the options for running the server application.

And to see the options for running the client application enter:

./rft_client

---

Ways to test the project

A test program is provided to test a subset of the rft_client_util library in isolation. The test program is test_rft_client_util. This does not test communication between client and server. It just tests some of the functions of the rft_client_util library.

The simplest way to build and run the test program is to enter the following command:

    make test

this will compile the test program and run it. It uses the same test framework as was used for assignment 1 and output is similar. Currently, tests are provided for init_protocol, init_segment and set_udp_socket functions.

---

An overview of input files

The following are the provided input files:

• in0.txt
• in1.txt
• in17.txt
• in34.txt
• in35.txt
• in36.txt
• in350.txt
• in660.txt

The number that follows "in" in the filename is the size of the file in bytes. The sizes have been chosen deliberately to test the following file transfer conditions:

• zero sized file
• boundary condition file sizes, e.g. one more than zero and sizes one off the significant file data in a data segment payload
• multiples of significant file data size
• a larger file to test random data segment loss

---

An overview of example log output files

The following files provide examples of the log output from the rft_client and rft_server:

• README-client-normal-tfr-out.txt
  output from the client for successful execution of a normal transfer

• README-server-normal-tfr-out.txt
  output from the server for successful execution of a normal transfer

• README-client-normal-tfr-err.txt
  output from the client when there is an error in a normal transfer

• README-client-timeout-tfr-out.txt
  output from the client for successful execution of a transfer with timeout

• README-server-timeout-tfr-out.txt
  output from the server for successful execution of a normal transfer

• README-client-timeout-tfr-err.txt
  output from the client when there is an error in a transfer with timeout

---