Classless IP addressing means that the IP address and the SUBNET mask of the device can belong to different classes.
There are three classes of IP addresses: A, B, and C. Each class covers a different of the range of the first octet of the IP Addresses:
Class A: 1-126
Class B: 128-191
Class C: 192-223
For example, 192.168.1.1 is a class C and 220.127.116.11 is class A IP address.
The classes for the Subnet mask is a little different. The classes are as follows:
Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0
It is possible to use a Subnet that is greater than the minimum values listed above. However, it would be inconsistent to use a Subnet lower than those values.
Below are examples of appropriate and inappropriate examples of IP/Subnet pairs:
Right: IP 10.168.68.10 Subnet 255.0.0.0
Right: IP 10.168.68.10 Subnet 255.255.248.0
Wrong: IP 192.168.1.1 Subnet 255.0.0.0
ION Meters support classless IP addressing.