Computer Science (0478) | Network hardware

Welcome to Network Hardware!

Have you ever wondered how your phone connects to Wi-Fi, or how your computer sends a request to a server thousands of kilometers away? It all relies on specialized pieces of physical equipment—the network hardware.
In this chapter, we will look at the essential components that allow your computer to communicate: the Network Interface Card (NIC), the two types of addresses (MAC and IP), and the vital role of the router.

Don't worry if networking concepts seem complicated; we'll break them down using simple analogies! By the end of this section, you will understand the hardware working behind the scenes every time you connect online.

1. The Network Interface Card (NIC)

What is a NIC and why is it needed? (3.4.1)

The first step for any device to join a network is having the right equipment to physically connect. This equipment is the Network Interface Card (NIC).

• A NIC is a piece of hardware that allows a computer to access a network, whether that network uses cables (Ethernet) or radio waves (Wi-Fi).
• Every computer, laptop, tablet, or server that connects to a network must have a NIC.
• It converts the data the computer understands into the signals that can travel over the network medium (like copper wires or radio frequencies).

Key Takeaway: The NIC is the essential physical gateway that makes network access possible.

2. Network Addresses: Identity and Location

To send and receive data correctly, every device on a network needs an address. Actually, it needs two different addresses that serve different purposes: the MAC address and the IP address.

2.1 Media Access Control (MAC) Address (3.4.2)

The MAC address is the device's unique, permanent, physical identity.

Purpose of the MAC Address:

• It is used to identify devices within a local network (LAN).
• It is essential for ensuring data packets reach the correct hardware interface once they arrive at the local area network.

Characteristics and Structure:

• It is assigned to the NIC at the point of manufacture. This means it cannot be changed (it's hard-coded).
• MAC addresses are typically written in hexadecimal format (base 16).
• A MAC address is usually split into two parts:
  1. The first part is the Manufacturer Code (unique to the company that made the NIC).
  2. The second part is the Serial Code (unique serial number for that specific device).
• Example: 00-1A-C2-7B-00-47 (The first three pairs identify the manufacturer).

2.2 Internet Protocol (IP) Address (3.4.3)

The IP address is the logical address used for routing data between different networks, especially across the internet.

Purpose of the IP Address:

• It identifies a device's current location on a network, allowing routers to direct data correctly across the globe.
• Unlike the MAC address, the IP address is allocated by the network (usually by the router).

Types of IP Addresses:

• Static IP Address: An address that is manually set and never changes. This is often used for servers or printers.
• Dynamic IP Address: An address that is assigned temporarily when the device connects to the network. This is the most common type for laptops and phones.

IPv4 versus IPv6

There are currently two main standards for IP addresses:

Key Takeaway: MAC addresses identify the physical device locally; IP addresses identify the device's logical location globally for routing.

3. The Router: The Network Traffic Controller

You might have a router sitting in your house, but do you know what crucial roles it performs? The router is arguably the most important piece of network hardware for managing connections.

Roles of the Router in a Network (3.4.4)

A router has three primary jobs:

1. Connecting Networks (Gateway to the Internet)

A router acts as the bridge between your internal Local Area Network (LAN) and the wider Internet (WAN).

• It connects your local devices (laptops, phones) to the rest of the world via your Internet Service Provider (ISP).

2. Routing Data to Specific Destinations

The router is responsible for examining the destination IP address contained in every data packet.

Step-by-Step Routing Process:

1. A device wants to send a data packet (e.g., requesting a webpage).
2. The packet includes the recipient's IP address.
3. The router receives the packet.
4. The router consults its internal routing table to determine the most efficient path for that packet to reach its specific destination.
5. It forwards the packet along that determined route.

3. Assigning IP Addresses (DHCP Server)

Most home and small office networks use Dynamic IP addresses.

• The router typically functions as a Dynamic Host Configuration Protocol (DHCP) server.
• When a new device connects, the router automatically assigns it a unique, temporary IP address, making network management easy.

Key Takeaway: The router connects the local network to the internet and directs data packets using IP addresses to ensure they reach their correct global destination.

Quick Review: Network Hardware Essentials

You now have a solid understanding of the fundamental hardware needed to build and manage a network! Keep practicing these concepts—they form the basis of all modern communication.