CPE 401/601 Computer Network Systems

Spring 2015

Assignment 3: IoT Interaction

Due on Monday, Mar 27, at 1:00 pm


In this assignment, we will develop a simple proxy for IoT devices that will allow them to communicate with each other within the LAN and other devices at WAN.

The code that you develop in this part will serve as a basis for the following programming assignments. You must create a pair of programs (client and server). The server (a PC) will act as a central repository where clients (a Raspberry PI) will post and access messages. All communications happen through the server. Clients establish a TCP session with the server when they become online and open a UDP port to be able to communicate with other devices. Clients also notify the server when they terminate.

The server code should be started with a parameter of port-number. Similarly, client code should be started with parameters of user-ID, server-IP, and server-port (all separated with spaces).

For this part of the assignment you need to implement multi threaded communication with devices and the server. Each client will register with the server and be able to communicate with each other simultaneously. Server will also be able to serve multiple clients simultaneously. You will need to use synchronization among threads and rely on mutexes to work with shared resources.

As measurement, we will run ping and traceroute from each client to a website and exchange the results with other clients. That is, once ping/traceroute is completed, it will be sent to other peers using UDP and all devices will record all data in a file.

Message Formats

Following are the application level messages sent from/to the server using TCP sockets:

Following are the application level messages sent between IoT devices using UDP sockets:


Report all major actions as the program communicates with other server/users in a file named Activity.log.

We assume device-IDs to be at most 32 characters without any white space characters.

When a malformed message is received report it in a log file named Error.log.

You may utilize localhost ( or actual IP address) to test your program by running multiple users on the same machine but within different folders (with different port numbers).

If testing on multiple machines, be sure that the machines are not behind a NAT (or within the same subnet).

You might get TCP messages in multiple segments even one byte at a time. Hence, you must check whether you have read all the message when parsing them (TCP streams).


You must submit all the source code in Python with sufficient comments to help understand the code.

You must include in your submission a file named Readme.txt that includes your name and a brief description of your submission, including the name of each file submitted along with a one line description of what is in the file.

If your code is not complete, tell us what works and what doesn't in Readme.txt file. If you are submitting code that does not compile, please tell us that as well. If you borrow code from someone else, you are required to tell us about it (this must also be documented in the code itself).

Finally, feel free to include a description of any problems you had or anything else you think might be helpful to us.


You should work individually.

Your project will be tested to make sure it works properly.

Your grade will depend on the functionality and the code quality. Hence, please pay careful attention to clean, modular and extensible design as you implement the project.

There will be bonus grades for extra functionality (such as a well designed GUI) not required by the project (optional and at the discretion of the instructor).

There will be bonus for students that point to major issues or add to program structure.


This document will evolve as we discuss the project and determine communication protocols and messaging formats.

Don't wait till the last minute to start this phase!

Last updated on Mar 6, 2017