Determining whether devices are on the same subnet, Preliminar y – Extron Electronics Matrix 12800 Series User Guide User Manual

Page 128

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A-7

Matrix 12800 Switchers • Ethernet Connection

PRELIMINAR

Y

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 (figure A-6). Each 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

address of the local and remote devices addresses are unmasked.

Unmasked octets are compared (indicated by ? in figure A-6).

If the subnet mask octet contains the value 0, the related octets of the IP

addresses of the local and remote devices are masked.

Masked octets are not compared (indicated by X in figure A-6).
If the unmasked octets of the two IP addresses match (indicated by = in figure A-6)

(example 1), the two addresses are on the same subnet.
If the two unmasked fields do not match (indicated by ≠ in figure A-6) (example 2

and example 3), the addresses are not on the same subnet.

192.168.254.254
255.255.0.0 (?.?.X.X)
192.168.2.25
=.=.X.X

Match

(Same subnet)

(Different subnet)

(Different subnet)

Local IP Address:

Subnet Mask:

Remote IP Address:

Match?:

Example 1

Example 2

192.168.254.254
255.255.0.0 (?.?.X.X)
190.190.2.25

≠.≠.X.XNo match

Example 3

192.168.254.254
255.255.0.0 (?.?.X.X)
192.190.2.25

=.≠.X.XNo match

Figure A-6 Comparing the IP addresses

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