Description

The objective of this MP0 is to create a simple network application. It contains two tasks described as follows.
Task1 is to implement an event logger that receives messages from multiple network nodes and stores them in a centralized log. The logger should be able to receive messages from the network nodes using the Python script generator.py, which generates messages for random events. The rate of generated events/messages can be controlled using two input arguments. The logger should also allow other network nodes to send their messages to it using TCP protocol on a specified port. The logger should then write the messages and node information into a log file, including the node name, connection time, messages, and disconnection time.
Task2 is to do an evaluation for this network. The log file produced by the network system can be evaluated to track two metrics: (1) the delay between event generation and recording in the log file, and (2) the network bandwidth used by the logger. The logger can use the current time when writing messages to the log file and count the number of bytes received from all network nodes over time. The metric values can be stored directly by the logger into a separate file or sent to standard output and redirected into a file by the shell.
Design Choices
To complete this machine problem, I developed two functions: logger.py and node.py. The logger.py function acts as a web server, collecting messages sent by the node.py function, which serves as a web client. The messages are generated by generator.py, including a timestamp and a random message. The communication between logger.py and node.py
functions is established through a TCP connection, allowing the transmission of messages between the two functions.
Prerequisites
Python 3.0+
socket, sys, time, threading, matplotlib. pyplot and numpy module in Python3
Usage
To do task1:
Start one terminal and run: python3 logger.py
Start any number of terminals (up to 24), and run: python3 -u generator.py 1 100 | python node.py (#Nodename) 127.0.0.1 1234
Start To do task2:
Three Nodes run parallel:
Logger: python logger.py 1234 2
Nodes Command: python3 -u generator.py RA(from 0.1-1) 100 | python3 node.py A 127.0.0.1 1234 &
python3 -u generator.py 1 100 | python3 node.py B 127.0.0.1 1234 & python3 -u generator.py 2 100 | python3 node.py C 127.0.0.1 1234
Data Analysis
In Task2, we define the delay and bandwidth as follows:
Delay:

Bandwidth:

Plots and Conclusion

As the sending rate of Node A increases, the delay decreases on the whole, while bandwidth is on the rise.
Bugs Encountered
Bug 1: sticky packet problem
Symptom: Sometimes, the logger can not split node_name with the first message, so the node_name is not correct, and the first message is missing.
Cause: The node send node_name and first message together, a typical TCP sticky packet problem (although TCP do not send packet).
Solution: Add a time.sleep() function after sending node_name
Authors
Zhanhao He 3190110713 Zhanhao.19@intl.zju.edu.cn
Bo Pang 3190110669 Bo.19@intl.zju.edu.cn