What is Subnetting ? | Classless and Classful Address | IP adressing

Subnetting is the process of dividing a large IP network into smaller subnetworks or subnets. It allows for efficient utilization of IP addresses, improved network management, and enhanced security. Subnetting is achieved by using subnet masks, which determine the network and host portions of an IP address.

Here are the key aspects of subnetting:

1. IP Address and Subnet Mask: Subnetting involves manipulating the subnet mask associated with an IP address. The subnet mask is a 32-bit binary value that determines the division between the network and host portions of an IP address. By modifying the subnet mask, you can create multiple subnets within a larger network.

2. Network Segmentation: Subnetting enables the division of a network into smaller logical subnets. Each subnet acts as an independent network, with its own range of IP addresses and subnet mask. This segmentation improves network performance, as traffic within a subnet remains local and does not need to traverse the entire network.

3. Subnet Identification: Each subnet within a network is identified by a unique subnet ID. The subnet ID is derived from the network address obtained by performing a logical AND operation between the IP address and the subnet mask. The subnet ID helps routers determine the appropriate path for forwarding packets within the network.

4. Subnet Size: The size of a subnet is determined by the number of host addresses it can accommodate. The subnet mask defines the number of bits allocated to the network and host portions. A smaller subnet mask (more bits allocated to the host portion) allows for more host addresses within the subnet, while a larger subnet mask (more bits allocated to the network portion) results in fewer available host addresses.

5. CIDR Notation: Classless Inter-Domain Routing (CIDR) notation is commonly used to represent subnets. CIDR notation combines the IP address and the number of network bits in the subnet mask. For example, an IP address of 192.168.1.0 with a subnet mask of 255.255.255.0 can be represented as 192.168.1.0/24 in CIDR notation, indicating that the first 24 bits represent the network portion.

6. Subnetting Benefits: Subnetting offers several advantages, including efficient use of IP addresses, improved network performance through localized traffic, enhanced security through isolated subnets, and easier network management by dividing a large network into smaller, manageable units.

When subnetting, it's important to plan the subnets carefully to ensure sufficient addresses are available for hosts in each subnet and to account for future growth. Network administrators must consider factors such as the number of hosts per subnet, scalability, network topology, and routing requirements.

Subnetting is a fundamental concept in IP networking that enables efficient allocation of IP addresses and facilitates the organization and management of complex networks.