This is the private address ranges for use by NON-routable segments. 
These private address ranges can be internally routed but will not 
   be routed accross the core of the internet. 

For more information see RFC 1918

Class Private Address Range 
A	10.0.0.0 ... 10.255.255.255 
B 	172.16.0.0 ... 172.31.255.255 
C	192.168.0.0 ... 192.168.255.255