Subnet Mask Assignment
Like an IP address, a subnet mask is most commonly expressed in a 32-bit dotted-decimal format. Unlike an IP address, though, a subnet mask performs just one function: It defines which parts of the IP address refer to the network address and which refer to the node address. Each of the classes of IP address used for address assignment has a standard subnet mask associated with it. The default subnet masks are listed in Table 3.
|
Address Class |
Default Subnet Mask |
|---|---|
|
A |
255.0.0.0 |
|
B |
255.255.0.0 |
|
C |
255.255.255.0 |