Subnet Masking - D-Link DES-3250TG User Manual

is the first octet (10.x.x.x). The node part of the address is the
last three octets (x.42.73.210).
To specify the network address for a given IP address, the node
part is set to all "0"s. In our example, 10.0.0.0 specifies the
network address for 10.42.73.210. When the node part is set to
all "1"s, the address specifies a broadcast address. So,
10.255.255.255 is the broadcast address for the network
10.0.0.0.

Subnet Masking

A subnet mask can be applied to an IP address to identify the
network and the node parts of the address. A bitwise logical
AND operation between the IP address and the subnet mask
results in the Network Address.
For example:
00001010.00101010.01001001.11010010
11111111.00000000.00000000.00000000
00001010.00000000.00000000.00000000
The Default subnet masks are:
•
Class A – 11111111.00000000.00000000.00000000
255.0.0.0
•
Class B – 11111111.11111111.00000000.00000000
255.255.0.0
•
Class C – 1111111.11111111.11111111.00000000
255.255.255.0
Additional bits can be added to the default subnet mask for a
given Class to further subnet a network. When a bitwise logical
AND operation is performed between the subnet mask and the
IP address, the result defines the Subnet Address.
Some restrictions apply to subnet addresses. Addresses of all
"0"s and all "1"s are reserved for the local network (when a host
does not know it's network address) and for all hosts on the
DES-3250TG Layer 2 Fast Ethernet Switch User's Guide
10.42.73.210 Class A IP address
255.0.0.0
10.0.0.0
43
Class A Subnet Mask
Network Address