Transfer-Protocol

Implementation of a transfer protocol without data loss for the course LINGI1341 – Réseaux informatiques, in 2016. Specifically, the protocol is intended to be used to transfer data between 2 computers.

It is built using UDP segments and uses IPv6. The data loss prevention is achieved thanks to CRC checksums, a go-back-n strategy and a selective repeat (on the receiver side). A graceful disconnect was also implemented to prevent losing the last segments.

Languages used:

• C
• Makefile (to automate compilations and test executions)
• bash (for the tests)

Collaborators

Even though this is a two people project, I made the code and report. My collaborator helped me at the time with the feature design, architecture and projects for other courses.

What I learned

• Interact with the network using C
• Find relevant information in C's manpages
• Implement and optimize communication protocols
• Automate command execution using makefiles
• Follow a (quite vague) protocol description close enough to make a protocol able of inter-operate with other protocols that follow the same guidelines

Files worth checking out

• The instructions (in French): consignes.pdf
• The report explaining what we made (in French): rapport.pdf
• The tests: tests/tests.sh
• Main functions of the receiver: src/receiver.c and src/receiverReadWriteLoop.c
• Main functions of the sender: src/sender.c and src/senderReadWriteLoop.c
• Packet definition: src/packets.c
• Network connections: src/createConnection.c

Compilation and execution

Compile the receiver on the first computer:

make receiver

Compile the sender on the second computer:

make sender

Run the receiver:

./receiver [<option>] <sender-IP> <port>

with -f <file-path> the path to the file where messages have to be taken from.

Run the sender:

./sender [<option>] <receiver-IP> <port>

with -f <file-path> the path to the file where messages have to be written to.

Run the tests:

make tests