TCP flow control (sliding window) in Computer Networks - Mini Project: Build & Apply

Understanding TCP Flow Control with Sliding Window

📖 Scenario: You are learning how computers manage data transmission over the internet using TCP (Transmission Control Protocol). TCP uses a method called sliding window to control the flow of data packets between sender and receiver, ensuring that the receiver is not overwhelmed.

🎯 Goal: Build a simple step-by-step model that represents the TCP sliding window mechanism. You will create data structures to represent the window size, the packets sent, and the acknowledgement process.

📋 What You'll Learn

Create a list of data packets numbered 1 to 10

Define a window size variable to control how many packets can be sent before waiting for acknowledgement

Simulate sending packets within the window using a loop

Update the window to slide forward after receiving acknowledgements

💡 Why This Matters

🌍 Real World

TCP sliding window is used in internet communication to ensure reliable and efficient data transfer without overwhelming the receiver.

💼 Career

Understanding TCP flow control is important for network engineers, software developers working on network applications, and cybersecurity professionals.

1

Create the list of data packets

Create a list called packets containing integers from 1 to 10 representing data packets.

Computer Networks

# Create the list of packets from 1 to 10
# Your code here

Need a hint?

Use the range function to create numbers from 1 to 10 and convert it to a list.

2

Define the window size

Create a variable called window_size and set it to 4 to represent the number of packets that can be sent before waiting for acknowledgement.

Computer Networks

packets = list(range(1, 11))
# Define the window size as 4
# Your code here

Need a hint?

Set window_size to 4 as an integer.

3

Simulate sending packets within the window

Use a for loop with variable i to iterate over the first window_size packets in packets and create a list called sent_packets containing these packets.

Computer Networks

packets = list(range(1, 11))
window_size = 4
# Use a for loop to send packets within the window
# Your code here

Need a hint?

Loop from 0 to window_size - 1 and add each packet to sent_packets.

4

Slide the window after acknowledgement

Create a variable called acknowledged and set it to 2 representing the number of packets acknowledged by the receiver. Then create a list called next_window containing the next set of packets after sliding the window by acknowledged positions.

Computer Networks

packets = list(range(1, 11))
window_size = 4
sent_packets = []
for i in range(window_size):
    sent_packets.append(packets[i])
# Set acknowledged to 2 and create next_window after sliding
# Your code here

Need a hint?

Set acknowledged to 2. Then loop from acknowledged to acknowledged + window_size - 1 to get the next packets.