Introduction to Networking

Subnetting and Its Types

  • Subnetting is a process in which a single network is divided into multiple sub-networks.
  • The sub-networks are also called subnets.

Example

The following figure shows the sub-networks of a large single network into 4 smaller sub-networks

Subnet ID

  • Each sub-network has its unique network ID known as its Subnet ID.
  • The subnet ID is created by borrowing some bits from the part of the Host ID.
  • The number of bits borrowed from hosts depends on the number of subnets created.

Types of Subnetting

Subnetting of a network can be achieved through the following methods

1. Fixed Length Subnetting

Fixed-length subnetting is also called classful subnetting. Fixed-length subnetting holds the following properties.

  • The sizes of all sub-networks are the same.
  • Subnets of all subnetworks are the same.
  • All the sub-networks have an equal number of hosts.

2. Variable Length Subnetting

Variable length subnetting is also called classless subnetting. Variable length subnetting holds the following properties.

  • The sizes of all sub-networks are not the same.
  • Subnets of all subnetworks are not the same.
  • None of the sub-networks have an equal number of hosts.

Advantages of Subnetting

Subnetting improves security because the administration and maintenance of sub-networks is easy.

In simple words, the management and maintenance of the entire university is tough as compared to its different departments.

Disadvantages of Subnetting

Point-01:

Subnetting leads to the loss of IP Addresses. Two IP Addresses are always wasted for every sub-network (subnet).In subnetting, One IP Address is wasted for its network address and another for its direct broadcasting address.

Point-02:

Subnetting leads to a more complicated communication process than communication without subnetting.

After subnetting, the communication is done through the following 4 steps

  • First, Identifying the network
  • Second, Identifying the sub-network
  • Third, Identifying the host
  • And in the last, Identifying the process