Network Hardware

2026 Syllabus Objectives

By the end of this topic, you should be able to:

  1. Understand that a computer needs a network interface card (NIC) to access a network
  2. Understand what is meant by, and the purpose of, a media access control (MAC) address, including its structure
  3. Understand what is meant by, and the purpose of, an internet protocol (IP) address, and that there are different types of IP address
  4. Describe the role of a router in a network

1. Network Interface Card (NIC)

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What is a Network Interface Card?

A Network Interface Card (NIC) is a piece of hardware (a physical component) that a computer needs to connect to a network. Think of it as a "network connector" built into or added to your device.

Key points about NICs:

  • Every computer that wants to join a network must have a NIC
  • A NIC can be wired (connects using cables, like an Ethernet cable) or wireless (connects using Wi-Fi signals)
  • The NIC allows your computer to send data to other devices on the network and receive data from them
  • Without a NIC, a computer cannot communicate with other devices on a network at all

Real-world example: When you connect your laptop to your home Wi-Fi, you're using a wireless NIC. When you plug an Ethernet cable into your computer, you're using a wired NIC.

2. Media Access Control (MAC) Address

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What is a MAC Address?

A MAC address (Media Access Control address) is a unique identification number that is permanently assigned to a device's network interface card. It's like a serial number that identifies your specific device on a network.

Important facts about MAC addresses:

  • Every NIC is given a MAC address at the point of manufacture (when it's made in the factory)
  • MAC addresses are static, which means they never change throughout the device's lifetime
  • Even if you move your device to a completely different network, the MAC address stays the same
  • MAC addresses are used mainly on local area networks (LANs) to identify devices
  • The MAC address makes it possible for network switches to send data to the correct device

Structure of a MAC Address

MAC addresses are written using hexadecimal (base-16) numbers. This is a number system that uses 16 digits: 0-9 and A-F.

Format: A MAC address is made up of 48 bits (6 bytes) of data, which is displayed as 12 hexadecimal digits grouped into 6 pairs, separated by hyphens or colons.

Example: 00-1C-B3-4F-25-FE

The Two Parts of a MAC Address

Every MAC address has two parts:

1. Manufacturer Identity Number (First 3 pairs)

  • The first three pairs of hexadecimal digits identify who manufactured the device
  • This is also called the Organisationally Unique Identifier (OUI)
  • Different companies have different manufacturer codes

2. Serial Number (Last 3 pairs)

  • The last three pairs are the serial number of the specific network interface card
  • This makes each device unique, even if they're made by the same manufacturer

Example breakdown:

MAC Address: 00-1C-B3-4F-25-FE

  • Manufacturer ID: 00-1C-B3 (this code belongs to Apple Corporation)
  • Device Serial Number: 4F-25-FE (this identifies this specific device)

Other manufacturer examples:

  • 00-14-22 = Dell
  • 00-40-96 = Cisco
  • 00-A0-C9 = Intel

Why MAC Addresses Use Hexadecimal

Hexadecimal is used because:

  • It's much shorter and easier to read than binary
  • There are enough possible MAC addresses for approximately 281 trillion devices
  • It makes it easier for network engineers to work with addresses

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