IP Address Classes and Subnetting

Classes of IP Address

Class A

• Range: 1.0.0.0 to 126.255.255.255
• Default Subnet Mask: 255.0.0.0 or /8
• Purpose: Large networks; suitable for very large organizations
• Number of Networks: 128 (0-127)
• Hosts per Network: Approximately 16 million (16,777,214 usable addresses)

Class B

• Range: 128.0.0.0 to 191.255.255.255
• Default Subnet Mask: 255.255.0.0 or /16
• Purpose: Medium to large networks; used by universities and large businesses
• Number of Networks: 16,384 (128-191)
• Hosts per Network: Approximately 65,000 (65,534 usable addresses)

Class C

• Range: 192.0.0.0 to 223.255.255.255
• Default Subnet Mask: 255.255.255.0 or /24
• Purpose: Small networks; common in small businesses and home networks
• Number of Networks: 2,097,152 (192-223)
• Hosts per Network: 254 usable addresses

Subnetting

• Definition: Dividing a larger network into smaller, more manageable subnetworks.
• Purpose:
  • Improves routing efficiency
  • Enhances security
  • Optimizes IP address usage
• Subnet Mask: Determines the network and host portions of an IP address.
• CIDR Notation: Example: /24 indicates 24 bits for the network part, leaving the rest for hosts.
• Benefits:
  • Reduces broadcast domains
  • Facilitates easier network management
• Methods:
  • Fixed-size subnetting
  • Variable-length subnet masking (VLSM)

Classes of IP Address

• Class A addresses are used for large networks, like those of very large organisations.
• Class B addresses are suitable for medium to large networks and are often used by universities and businesses that need larger networks.
• Class C addresses are typically used for small networks as they are commonly found in small businesses and home networks.
• Class A addresses have a range of 1.0.0.0 to 126.255.255.255 and a default subnet mask of 255.0.0.0, which is also represented as /8 in CIDR notation.
• Class B addresses have a range of 128.0.0.0 to 191.255.255.255 and a default subnet mask of 255.255.0.0 or /16.
• Class C addresses have a range of 192.0.0.0 to 223.255.255.255 and a default subnet mask of 255.255.255.0 or /24.
• There are 128 Class A networks, 16,384 Class B networks and 2,097,152 Class C networks.
• Each Class A network can accommodate approximately 16 million hosts (16,777,214 usable addresses), while Class B networks accommodate around 65,000 hosts (65,534 usable addresses).
• Class C networks can hold 254 usable addresses in total, while the remaining address is for network purposes.

Subnetting

• Subnetting is the process of dividing a larger network into smaller, more manageable subnetworks.
• It improves routing efficiency, enhances security, and optimizes IP address usage.
• The subnet mask determines the network and host parts of an IP address.
• CIDR notation, such as /24, represents the number of bits used for the network part, leaving the remaining bits for hosts.
• Subnetting reduces broadcast domains, making network management easier.
• Two main types of subnetting include:
  • Fixed-size subnetting
  • Variable-length subnet masking (VLSM)

This quiz covers different classes of IP addresses including Class A, B, and C, detailing their ranges, purposes, and subnet masks. Additionally, it introduces the concept of subnetting, which involves dividing larger networks into smaller, manageable parts. Test your knowledge on network classification and subnetting!