When connected to the internet, every device is assigned a unique IP address. A network is more efficient as a delivery service when a message travels with as few hops as possible. When data packets travel between networks, they will be routed by subnets so that the data packets take an efficient route to their final destination. An IP address determines the address of the data packet, whether it be at the source or destination. 

Every Ip address has two parts and the first part indicates the network the address belongs to, and the second shows the device in the network. However, the first part of an IP address can change based on its network class. So if an IP address makes it simple for the internet router to find the right network for data to route into, why do we need Subnetting?

A million devices could be connected to a particular network. It could take several hops and significant time for the data to reach the correct address, which is where subnetting comes in handy. Subnetting trims down the IP addresses to practice within a range of devices. 

Subnetting helps in organizing the network to overcome network congestion. When network traffic increases within parts of the network, it groups these parts into one section so that the traffic does not unnecessarily hop across the entire network. Subnetting also efficiently designates IP addresses and prevents a vast number of IP addresses from going unused. 

How do we use subnetting? 

IP addresses are divided into three classes: A, B, and C.

• Class A: IP addresses lie between 0.0.0.0 and 127.255.255.255.

• Class B: IP addresses lie between 128.0.0.0 and 191.255.255.255.

• Class C: IP addresses lie between 192.0.0.0 and 223.255.255.255.

These IP address classes help formulate subnet masking. Based on classes A, B, C, here are the default masks:

• Class A: 255.0.0.0

• Class B: 255.255.0.0

• Class C: 255.255.255.0

Subnetting creates several logical networks that live within a single class network. When a major network is separated into smaller subnets, it establishes an interconnecting subnetwork. 

For example:

With the three bits from the original portion, it creates eight subnets. With the remaining five host ID bits, each subnet can have up to 32 host addresses, 30 of which can be assigned to a device as hosts ids of all zeros or all ones are not allowed.

The more bits one uses in the subnet, the more subnets there will be available.