Certainly, let's continue to delve into the concept of CIDR (Classless Inter-Domain Routing) and its benefits:

Address Classes and Subnetting:

• Address classes (A, B, C) were an initial attempt to organize the global Internet IP space.
• Traditional subnetting with address classes was limited by fixed network ID lengths (8, 16, or 24 bits).
• Class C networks (24-bit) allowed for many individual networks, but with limited host addresses.
• Class B networks (16-bit) offered more host addresses but often too many for smaller networks.

CIDR: Classless Inter-Domain Routing:

• CIDR was introduced as a more flexible and efficient approach.
• CIDR abandons the concept of address classes and focuses on network mask-based demarcation.
• CIDR eliminates the need for rigid class-based distinctions and focuses on efficient subnet allocation.
• Demarcation point: The point where one network or system ends and another begins.

CIDR Notation:

• CIDR introduces shorthand slash notation, also known as CIDR notation.
• Example: Instead of writing out 9.100.100.100 with a subnet mask of 255.255.255.0, you can use 9.100.100.100/24.
• CIDR notation specifies the number of bits set to 1 in the subnet mask (i.e., the length of the network portion).

Simplification and Flexibility:

• CIDR combines network ID and subnet ID into a single concept.
• Routers and network devices no longer need to distinguish between classes; they focus on subnet masks.