TCP_Protocol | Elijah Gaohan Ye

By the collaboration of Elijah Ye and Ananya Kommalapati
UIUC CS438 FA23 | September 2023 ~ October 2023

We used UDP to implement our own version of TCP. We are able to tolerate packet drops, allow other concurrent connections a fair chance, and it is not overly nice to other connections (should not give up the entire bandwidth to other connections).

Running the Program

In order to run the program, you need to have two VM instances. In our case, we used VirtualBox and fired up two Linux VM instances on our local machine. For more information, please check the original github repository.

Client

$ make
$ ./reliable_receiver

Server

$ make
$ ./reliable_sender [hostname] [port] [filename] [bytesToTransfer]

To run program with customized speed and drop rate

If your network interface inside the VM is eth0, then run (from inside the VM) the following command:

$ sudo tc qdisc del dev eth0 root 2>/dev/null

to delete existing tc rules. Then use,

$ sudo tc qdisc add dev eth0 root handle 1:0 netem delay 20ms loss 5%

followed by

$ sudo tc qdisc add dev eth0 parent 1:1 handle 10: tbf rate 20Mbit burst 10mb latency 1ms

will give you a 20Mbit, 20ms RTT link where every packet sent has a 5% chance to get dropped. Simply omit the loss n% part to get a channel without artifcial drops. (You can run these commands just on the sender; running them on the receiver as well won’t make much of a difference, although you’ll get a 20ms RTT if you don’t adjust the delay to account for the fact that it gets applied twice.)

Academic Integrity

Please review the University of Illinois Student Code, particularly all subsections of Article 1, Part 4 - Academic Integrity Policy and Procedure.

Legal Notice

This work is protected under the GNU General Public License v3.0.
Copyright (c) 2024 Elijah Gaohan Ye, Ananya Kommalapati, Romit Roy Choudhury

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose, without fee, and without written agreement
is hereby granted, provided that the following two paragraphs appear
in all copies of this software.

IN NO EVENT SHALL THE AUTHOR OR THE UNIVERSITY OF ILLINOIS BE LIABLE TO
ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,
EVEN IF THE AUTHOR AND/OR THE UNIVERSITY OF ILLINOIS HAS BEEN ADVISED
OF THE POSSIBILITY OF SUCH DAMAGE.

THE AUTHOR AND THE UNIVERSITY OF ILLINOIS SPECIFICALLY DISCLAIM ANY
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND NEITHER THE AUTHOR NOR
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