Extron Electronics VN-MATRIX User Guide - Manual (Page 126)

Appendix A: Guide to IP Addressing VN-MATRIX User Guide
Page 126 I458GB issue 6
Choosing IP Addresses
If your VN-MATRIX units are connected via their own independent network, then follow the guidelines
below for choosing your IP Addresses.
However, if you intend connecting your VN-MATRIX units to an existing network, you will need to
advise the network administrator and ask them to allocate suitable addresses to you.
On an independent network you can (in theory) use just about any addresses you wish. However, it is
generally recommended that you use the Class C format (i.e. from 192.0.0.1 up to 223.255.255.253).
Remember that there are two rules for choosing IP Addresses:
• the network identifier must be the same for each address, and
• the host identifier must be unique for each address.
Applying these rules to Class C addresses, it can be seen that the first three decimal values of your IP
Addresses must all be the same, while the last value is used to uniquely identify each device.
The following is an example of a valid Class C addressing scheme:
Device IP Address
Device 1 208.132.180.41
Device 2 208.132.180.42
Device 3 208.132.180.43
NOTE: The host identifiers (e.g. 41, 42, and 43 in the above example) need not be sequential or in
any particular order. However, it is recommended that you group the numbers for simplicity.
The following is an example of an invalid Class C addressing scheme:
Device IP Address
Device 1 208.132.180.41
Device 2 192.157.180.42
Device 3 209.100.123.43
NOTE: These are invalid because the network identifier for each address is not the same, even
though each IP Address is unique.
You can use the Ping command from your computer to check that a device at a particular address is
responding correctly (see page 127).
Subnet Mask
The Subnet Mask is another 32-bit binary number that is used to ‘mask’ certain bits of the IP Address.
This provides a method of extending the number of network options for a given IP Address. It works
by allowing part of the host identifier to be used as a ‘subnet identifier’. Any further explanation of this
facility is not relevant here.
However, it is important that you set the correct value for the Subnet Mask. The basic values depend
on the class of IP Address being used:
Class Name Subnet Mask
Class A 255.0.0.0
Class B 255.255.0.0
Class C 255.255.255.0