ICS 156: Networking Lab

Subnet Masks and Addresses 2/2

nNew Format for Subnet Masks:

–130.91.66.100/24, or 130.91.66.100/22

nIf we use 4 bits for subnetting how many subnets can we have?

–> 24=16. Note that this is true for the new Internet routing protocols (RIP II, OSPF, etc.) called classless routing algorithms. The old classfull routing algorithms did not allow all 1’s or all 0’s. New routing algortihms send subnet mask along with IP address, old algorithms relied on IP address class recognition (A, B, C, etc.)