Subnetting Concept

Subnetting makes it possible to divide a large network IP address space into several smaller,more manageable "subnets."

The example on the slide shows a subnetted /16 network. Without subnetting, the 128.1.0.0/16 network would have 65 thousand hosts on the same physical network, which could easily lead to excessive collisions

This network, however, has been subdivided into 254 subnets. Each of these subnets could potentially have up to 254 hosts.

Subnet Addresses
----------------
128.1.1.0
128.1.2.0
...
128.1.253.0
128.1.254.0

Subnets are separated from one another by routers, which overcome both the collision and topological issues discussed on the previous slide.

Subnetting also makes it easy for the network administrator to delegate authority for
portions of the IP network address space to other entities within the organization. Simply assign each department a separate subnet. Each network administrator then becomes responsible for a subnet within the larger corporate network