Network Hardware (Copy)

Network Interface Card (NIC)

• Definition:
  • A Network Interface Card (NIC) is a hardware component that allows a computer or device to connect to a network (wired or wireless).
  • It may be integrated into the motherboard or added as an expansion card.
• Functions:
  • Provides the physical interface between the device and the network medium (Ethernet cable or wireless signal).
  • Handles data link layer protocols (e.g., Ethernet, Wi-Fi) for communication.
  • Converts data from the computer into signals suitable for transmission over the network and vice versa.
• Key Points:
  • Without an NIC, a computer cannot access a network.
  • Modern devices often have both wired (Ethernet) and wireless (Wi-Fi) NICs.
  • NICs have a unique MAC address burned into them at manufacture.

Media Access Control (MAC) Address

• Definition:
  • A MAC address is a unique identifier assigned to a NIC by the manufacturer.
  • It operates at the data link layer of the OSI model.
• Structure:
  • Format: 48 bits (6 bytes), usually expressed in hexadecimal.
  • Written as six pairs of hexadecimal digits separated by colons (:) or hyphens (−).
    • Example: 00:1A:2B:3C:4D:5E.
• Components:
  • First 24 bits: Organisationally Unique Identifier (OUI) – identifies the manufacturer.
  • Last 24 bits: Device-specific serial number.
• Purpose:
  • Used for identifying devices within a local area network (LAN).
  • Essential in Ethernet switching for directing frames to the correct device.
  • Cannot be changed permanently (burned into hardware), but can be spoofed temporarily by software.
• Example in Use:
  • When you connect to Wi-Fi, the router uses the MAC address to recognise your device.

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Internet Protocol (IP) Address

• Definition:
  • An IP address is a logical address assigned to a device so it can communicate over a network using the Internet Protocol.
• Purpose:
  • Identifies the device’s location on a network.
  • Allows communication between devices over LAN, WAN, or the Internet.
• Types of IP Address:
  1. Static IP Address:
     • Manually assigned, does not change.
     • Suitable for servers and network devices needing a constant address.
  2. Dynamic IP Address:
     • Assigned automatically by a DHCP server.
     • Changes periodically, ideal for most users.
• Versions:
  • IPv4:
    • 32-bit address, written in dotted decimal notation (e.g., 192.168.0.1).
    • Around 4.3 billion possible addresses.
  • IPv6:
    • 128-bit address, written in hexadecimal separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).
    • Provides an almost unlimited number of addresses.
• Differences between IPv4 and IPv6:

Role of a Router in a Network

• Definition:
  • A router is a networking device that forwards data packets between computer networks.
• Functions:
  • Determines the best path for data to travel from source to destination.
  • Uses IP addresses to route data between devices across LANs, WANs, and the Internet.
  • Can connect a local network to the Internet.
• Key Features:
  • Assigns IP addresses using DHCP (Dynamic Host Configuration Protocol).
  • Maintains a routing table to decide how to forward data packets.
  • Provides Network Address Translation (NAT) to allow multiple devices to share a single public IP address.
• Example in Use:
  • In a home network, the router directs incoming and outgoing traffic between your devices and your Internet Service Provider (ISP).

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Summary Table of Components

Exam Tips

• Always remember:
  • MAC = Physical address, permanent (unless spoofed).
  • IP = Logical address, can be static or dynamic.
  • NIC = Needed for any network connection.
  • Router = Forwards packets, assigns IPs, connects networks.
• Be able to compare IPv4 and IPv6 in an exam.
• Know how to identify MAC vs IP addresses in a given question.

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course