What is one main reason cidr is helpful in modern networking?

CIDR (Classless Inter-Domain Routing) is helpful in modern networking because it allows for more efficient use of IP addresses.

Before CIDR, IP addresses were divided into classes (Class A, B, C) which dictated the size of the network and the number of hosts that could be connected to it. This led to the inefficient allocation of IP addresses, as organizations were often assigned more addresses than they needed or had too few addresses for their requirements.

CIDR allows for the flexible allocation of IP addresses by using variable length subnet masking (VLSM) to divide IP address ranges into smaller, more granular subnets. This means that organizations can request the exact number of IP addresses they need, leading to a more efficient use of address space and reducing the overall waste of IP addresses.

In addition, CIDR enables route aggregation, where multiple smaller IP address blocks can be combined into a single, larger block. This reduces the size of routing tables and the complexity of routing protocols, leading to faster and more efficient routing in large networks.

Overall, CIDR plays a key role in modern networking by enabling efficient allocation of IP addresses, reducing waste, and improving the scalability and performance of networks.