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# What is Subnetting and How is it Calculated

Subnetting is a technique used in computer networking to divide a large network into smaller sub-networks, also known as subnets.

Subnetting is a technique used in computer networking to divide a large network into smaller sub-networks, also known as subnets. This is done to optimize network performance and manage IP address allocation efficiently. Each subnet has its own unique network address, which is used to identify and route data within that particular subnet.

In subnetting, a portion of the host bits in an IP address is used to create a network ID, leaving the remaining bits to identify the host within that network. The number of bits used for the network ID is determined by the subnet mask, which is a 32-bit value used to divide an IP address into network and host portions.

The most commonly used IP address classes are A, B, and C, and the subnetting process differs slightly for each of these classes.

## Class A subnetting:

Class A IP addresses have an 8-bit network ID and a 24-bit host ID. To subnet a Class A network, you can use the subnet mask 255.0.0.0. This means that the first 8 bits of the IP address represent the network ID, and the remaining 24 bits represent the host ID. By borrowing bits from the host ID portion, you can create smaller subnets with their own network IDs. For example, if you want to create 16 subnets from a Class A network, you would borrow 4 bits from the host ID portion, leaving 20 bits for the host ID and creating 16 subnets, each with 2^20 (1,048,576) possible host addresses.

## Class B subnetting:

Class B IP addresses have a 16-bit network ID and a 16-bit host ID. To subnet a Class B network, you can use the subnet mask 255.255.0.0. This means that the first 16 bits of the IP address represent the network ID, and the remaining 16 bits represent the host ID. By borrowing bits from the host ID portion, you can create smaller subnets with their own network IDs. For example, if you want to create 64 subnets from a Class B network, you would borrow 6 bits from the host ID portion, leaving 10 bits for the host ID and creating 64 subnets, each with 2^10 (1,024) possible host addresses.

## Class C subnetting:

Class C IP addresses have a 24-bit network ID and an 8-bit host ID. To subnet a Class C network, you can use the subnet mask 255.255.255.0. This means that the first 24 bits of the IP address represent the network ID, and the remaining 8 bits represent the host ID. By borrowing bits from the host ID portion, you can create smaller subnets with their own network IDs. For example, if you want to create 8 subnets from a Class C network, you would borrow 3 bits from the host ID portion, leaving 5 bits for the host ID and creating 8 subnets, each with 2^5 (32) possible host addresses.

In summary, subnetting is the process of dividing a large network into smaller subnets to optimize network performance and manage IP address allocation efficiently. The subnetting process differs slightly for Class A, B, and C IP addresses, and it involves borrowing bits from the host ID portion of the IP address to create smaller subnets with their own unique network IDs.

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# Dikky Ryan Pratama

61 posts | 14 followers

## 5658210956348350 March 20, 2024 at 5:39 pm

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# Dikky Ryan Pratama

61 posts | 14 followers

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