Determining Whether Devices Are on the Same Subnet
To determine the subnet, the IP address of the local device is compared to the IP address
of the remote device (see figure 76). The octets of each address are compared or not
compared, depending on the value in the related subnet mask octet.
If a subnet mask octet contains the value 255, the related octets of the IP addresses of
•
the local device and the remote device are unmasked.
Unmasked octets are compared (indicated by
If the subnet mask octet contains the value 0, the related octets of the IP addresses of
•
the local device and remote device are masked.
Masked octets are not compared (indicated by
If the unmasked octets of the two IP addresses match (indicated by
the two addresses are on the same subnet.
If the two unmasked fields do not match (indicated by
example 3), the addresses are not on the same subnet.
Local IP Address:
Subnet Mask:
Remote IP Address:
Figure 76.
Example 1
192.168.254.254
255.255.0.0 (?.?.X.X)
192.168.2.25
Match?:
=.=.X.X
—
Match
(Same
subnet)
Comparing the IP Addresses of the Local and Remote Devices
FOX Matrix 3200 and 7200 Switchers • Ethernet Connection
?
in figure 76).
X
in figure 76).
=
in figure 76, example 1),
≠
in figure 76, example 2 and
Example 2
Example 3
192.168.254.254
192.168.254.254
255.255.0.0 (?.?.X.X)
255.255.0.0 (?.?.X.X)
190.190.2.25
192.190.2.25
≠.≠.X.X
—
No match
=.≠.X.X
(Different
subnet)
(Different
—
No match
subnet)
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