Extron Electronics MAV Plus Series - Manual (Page 177)

Ethernet Connection, cont’d
CrossPoint 450 Plus and MAV Plus Switchers • Ethernet Connection A-6
Subnetting — A Primer
It is not the purpose of this manual to describe TCP/IP protocol in detail.
However, some understanding of TCP/IP subnetting (a subnet is a subset of a
net
work — a set of IP devices that have portions of their IP addresses in common)
is necessary in order to understand the interaction of the CrossPoint 450 Plus or
MAV Plus switcher and the mail server gateway. To understand subnetting at the
level required to install and operate the CrossPoint 450 Plus or MAV Plus switcher,
you must understand the concepts of a gateway, local and remote devices, IP
addresses and octets, and subnet masks and octets.
Gateways
The CrossPoint 450 Plus or MAV Plus switcher can communicate with the e-mail
server that the switcher uses for e-mail notification directly (if they are on the same
subnet) or the communication can be routed via a gateway (a computer that
provides a link between different subnets).
Local and remote devices
The local and remote devices are defined from the point of view of the function
being described. In this manual, subnetting is an issue when you are using the
controlling PC to set TCP/IP and e-mail values in the CrossPoint 450 Plus or
MAV Plus switcher (see “IP Settings/Options window” in chapter 5, “Matrix
Software” and “Email Settings page” in chapter 6, “HTML Operation”). When you
are setting up the variables for e-mail notification, which may include subnetting,
the matrix switcher is the local device and the e-mail server is the remote device.
IP addresses and octets
Valid IP addresses consist of four 1-, 2-, or 3-digit numeric subfields, properly called
octets, separated by dots (periods) (figure A-4). Each octet can be numbered from
000 through 255. Leading zeroes, up to 3 digits total per octet, are optional. Values
of 256 and above are invalid.
192.168.254.254 Typical IP Address:
Octets
Figure A-4 — IP address and octets
Subnet masks and octets
The subnet mask (figure A-5) is used to determine whether the local and remote
devices are on the same subnet or different subnets. The subnet mask consists of
four numeric octets separated by dots. Each octet can be numbered from
000 through 255. Leading zeroes, up to 3 digits total per octet, are optional. Each
octet typically contains either 255 or 0. The octets determine whether or not the
same octets of two IP addresses will be compared when determining if two devices
are on the same subnet.
255.255.0.0 Typical Subnet Mask:
Octets
255 indicates that this octet will be
compared between two IP addresses.
0 indicates that this octet will not be
compared between two IP addresses.
Figure A-5 — Subnet mask and octets