Extron electronic 450 Plus, MAV Plus manual Determining whether devices are on the same subnet

Determining whether devices are on the same subnet

To determine the subnet, the local device’s IP address is compared to the remote device’s IP address (figure A-6). Each address’s octets 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 local device’s address and the remote device’s IP address 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 local device’s and remote device’s IP addresses 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.

	Example 1	Example 2	Example 3
Local IP Address:	192.168.254.254	192.168.254.254	192.168.254.254
Subnet Mask:	255.255.0.0 (?.?.X.X)	255.255.0.0 (?.?.X.X)	255.255.0.0 (?.?.X.X)
Remote IP Address:	192.168.2.25	190.190.2.25	192.190.2.25
Match?:	=.=.X.X — Match	≠.≠.X.X — No match	=.≠.X.X — No match
	(Same subnet)	(Different subnet)	(Different subnet)

Figure A-6 — Comparing the IP addresses

Ethernet Connection • Reference Information A-7