Data Movement and Types of Networks

Project Introduction

This project was focused on understanding how a LAN works, how data travels between devices on a LAN, and introducing binary, decimal, and hexadecimal numbers and their uses in networking applications.

• Planning and Design
• Technical Development
• Testing and Evaluation
• Reflection

Planning and Design

The main objectives for this project were to explore how Local Area Networks (LANs) enable communication between devices that are in the same environment (house, school, building, etc.), showcase how IP and MAC addresses are used to identify devices (as well as learning about their differences), and to learn to use ICMP tools to test connections and find details about devices on the LAN.

Components of a LAN and Representing them as Parts of a City

Important LAN Terms

Diagram of My House's LAN

In my house, almost everything is connected via Wi-Fi, except for the switch and Home Assistant Server that handles all of the smart home tasks in my house. Everything is directly connected to the router, which communicates with the internet and cloud services.

OSI Model - The Seven Layers of Networking

Networks are often represented by the OSI model, which consists of seven categories that encompass all networking-related tasks. They are:

OSI Cards Diagram

The following images showcase an activity about understanding how real-world examples are categorized into the OSI layers:

First Attempt

First attempt at matching OSI cards with example and ordering them correctly.

Correct Organization

Correct organization of OSI cards with their examples.

OSI vs TCP/IP Model

Representing Numbers with Different Bases

To demonstrate how number bases work, cards representing base-10 (decimal), base-2 (binary), and base-5 were provided. The task was to represent different numerical values with the different bases.

Base 10

501 = 5 * 10² + 0 * 10¹ + 1 * 10⁰ = 500 + 0 + 1 = 401

473 = 4 * 10² + 7 * 10¹ + 3 * 10⁰ = 400 + 70 + 3 = 473

324 = 3 * 10² + 2 * 10¹ + 4 * 10⁰ = 300 + 20 + 4 = 324

Base 5

84 (Decimal) = 3 * 5² + 1 * 5¹ + 4 * 5⁰ = 300 + 50 + 4 = 314 (Base-5) = 84 (Base-10)

37 (Decimal) = 1 * 5² + 2 * 5¹ + 2 * 5⁰ = 25 + 10 + 2 = 122 (Base-5) = 37 (Base-10)

Technical Development

In this section of the project, an Ubuntu VM was used to apply and verify networking concepts in the CLI.

Using Ubuntu to Convert Between Binary and Decimal

Converting between binary and decimal by hand is very difficult and tedious. Thankfully, the bc CLI tool can be used to perform the conversion.

To convert from binary to decimal, the command echo "obase=10; ibase=2; [Insert Binary Number]" | bc and echo "obase=2; 45" | bc can be used to convert from binary to decimal and from decimal to binary, respectively. Below is a breakdown of these commands:

Below is what these commands look like in the Ubuntu CLI:

Representing Network Information as Hexadecimal and Binary

Although decimal is easily readable by humans, computers process information in binary. Any time a computer works with decimal numbers, it first has to convert it to binary in order to do any operations with it. To see Ubuntu's IP address in binary, ipcalc must be installed with sudo apt install ipcalc -y. After installing it, run ipcalc [IP address] to display network information in binary.

Since hexadecimal can represent up to the number 15 in each character, it can store more information in less space when compared with decimal and especially compared to binary. To view network information in hexadecimal form in Ubuntu, the command printf '%02X%02X%02X%02X\n' 192 168 64 2, where 192, 168, 64, and 2 should be replaced with the digits from your IP address (found with ifconfig).

The output was C0A84002. Breaking this down:

• C0 = 192
• A8 = 168
• 40 = 64
• 02 = 2

MAC addresses are also written in hexadecimal form; each pair of characters represents a byte of the device's hardware address. To find the MAC address in Ubuntu, run ip addr show.

Exploring LAN Components through Ubuntu

Information about the LAN can be identified in Ubuntu through CLI commands such as ifconfig, ping, and traceroute. These three commands are essential for finding information about the LAN as well as troubleshooting.

What Each Command Does

Before running any of these commands, they had to be installed on the computer with sudo apt install net-tools -y to install ifconfig, sudo apt install iputils-ping -y to install ping, and sudo apt install traceroute -y to install traceroute.

ifconfig is mainly used to display information relating how a computer connects to the LAN. It outputs information such as inet, the IP address assigned to the computer, netmask, which defines the portion of the IP address identifies the network and device, and broadcast, which is used to send messages to all devices on the same LAN.

In the image above, inet, netmask, and broadcast are all outlined in red. Inet is the IP address of the computer (192.168.64.2). Netmask (255.255.255.0) defines which part of the IP address identifies the network, and which part identifies the device. When translated to binary, the netmask is 11111111.11111111.11111111.00000000. Each 1 means "network", and each 0 means "host", meaning that 192.168.64 identifies the network, and 2 identifies the device on the network. The range of valid IP addresses in the network would be anywhere from 192.168.64.1 - 192.168.64.254 (since 192.168.64.255 is the broadcast).

ping is mainly used to test internet connection and DNS. Pinging a public DNS server, such as 8.8.8.8 (Google's public DNS server) and 1.1.1.1 (Cloudflare's public DNS server), is a simple way to ensure that a computer can reach the internet. Once internet connection is verified, pinging a domain such as google.com or cloudflare.com can test the DNS. If 8.8.8.8 is reachable but google.com isn't, that means that there is an issue with the DNS. To run these commands in Ubuntu and macOS, run ping -c 4 8.8.8.8 then ping google.com. In the image below, a ping was sent to google.com and other domains, but they didn't respond. So, the DNS was reset with sudo resolvectl flush-caches, which made google.com and cloudlfare.com reachable. After each ping, the system prints how long the data took to travel to the domain, which is a good indicator of internet speed.

traceroute is used to show the route data takes to reach a destination. To test it with google.com (any domain will work), run traceroute google.com. This command will return a list of "hops" that show the path the data takes across routers to reach Google's server. When it was tested, the data took 23 "hops" and 55.121 ms to reach google.com.

The data from traceroute can be confusing. Below is a table explaining what each part of the output means:

In the example above:

• Hop 1: *_gateway (192.168.64.1) is the local network gateway (what connects the LAN to the internet)
• Hop 2-10: Local or ISP routers
• Hop 11-20: Internet backbone routers (large, powerful routers moving data across regions or countries)
• Hop 23: Google's server (64.233.176.113)

Roadmap Representing OSI Layers

**Reflection:

This roadmap represents a data packet as a plane flying from an airport to another airport. It represents the different OSI layers as aspects of an airport, such as the runway being the physical layer. I think that the Transport layer is the most important since it ensures that everything arrives safely and in order. This project helped me understand how the TCP/IP model is a simplified version of the OSI model but both aim to describe how data is transferred.

Testing and Evaluation

Throughout the activity, many labs were performed involving many different commands. Below, a table summarizes all of the commands used and their purpose.

Reflection

By working through the various labs exploring data movement, I learned how exactly data is transferred between devices, both over a LAN and through the internet. Learning about the OSI and TCP/IP models helped simplify and understand how data communication works. Designing a roadmap to visualize data transfer helped me understand OSI layers even better. Additionally, converting between binary, decimal, and hexadecimal helped me understand the different number systems and showed the different advantages of each system. By using ipcalc, I learned how IP addresses are represented in binary. Using ping and traceroute demonstrated the path that data takes to transfer from one system to another and demonstrated a real world application of the OSI layers.