Classful IP Addressing

Limitations of classful networking

can waste IP addresses

benefits of subnetting

upgrade infrastructure, subnet the network, reduces computers per subnet, and reduces broadcast traffic

CIDR components

network, subnet, and host

network portion

identifies the classful networksubnet

subnet portion

identifies specific subnet

host portion

identifies host addresses within subnet

CIDR step 1

calculate the mask for required subnets

CIDR step 2

calculate mask for required hosts

CIDR Step 3

Determine subnet boundaries

CIDR step 4

indetify valid IP addresses

Block Size 

value of the far right binary -1 bit subnet mask and is used to find the network IDsF

Finding Network IDs

• first network ID - classful netwirk address

• next network ID - previous network ID + block size

finding broadcast address

next network id -1

Variable Length Subnet Masking

Using subnet masks of varying lengths in network design to minimize IP Address waste