IP addresses are divided into classes based on their first octet. The three main classes are A, B, and C. Each class has a different range of possible values for the first octet and is used for different types of networks.
IP Classes:
- Class A:
- First Octet Range: 1-126
- Example: 10.0.0.1
- Default Subnet Mask: 255.0.0.0
- Reserved for very large networks
- Class B:
- First Octet Range: 128-191
- Example: 172.16.0.1
- Default Subnet Mask: 255.255.0.0
- Suitable for medium-sized networks
- Class C:
- First Octet Range: 192-223
- Example: 192.168.0.1
- Default Subnet Mask: 255.255.255.0
- Used for small networks
Public and Private IP Addresses:
- Public IP Address: These are routable on the Internet. They are unique and can be used to identify a device on the global network.
- Private IP Address: These are reserved for use within private networks and are not routable on the Internet. They are used for internal communication within a network.
Commonly used private IP address ranges:
- Class A: 10.0.0.0 to 10.255.255.255
- Class B: 172.16.0.0 to 172.31.255.255
- Class C: 192.168.0.0 to 192.168.255.255
Calculating IP Range:
When calculating the IP range for a subnet, you need to consider the network address, the usable IP addresses, and the broadcast address. Here’s a basic formula:
- Network Address: This is the base address of the subnet, obtained by setting all host bits to zero.
- Usable IP Addresses: All addresses between the network address and the broadcast address, excluding both.
- Broadcast Address: This is the last address in the subnet, obtained by setting all host bits to one.
Example:
- IP Address: 192.168.1.0
- Subnet Mask: 255.255.255.0
- Network Address: 192.168.1.0
- Usable IP Range: 192.168.1.1 to 192.168.1.254
- Broadcast Address: 192.168.1.255
Remember, these calculations may vary if you are using subnetting. Subnetting involves dividing a larger network into smaller sub-networks, allowing for better organization and utilization of IP addresses.