Ethernet Connection, cont’d
SMX System MultiMatrix Switchers
•
Ethernet Connection
A-8
Subnetting — A Primer
A subnet is a
sub
set of a
net
work — a set of IP devices that have portions of
their IP addresses in common. It is not the purpose of this manual to describe
TCP/IP protocol in detail. However, some understanding of TCP/IP subnetting
is necessary in order to understand the interaction of the SMX switcher and the
mail server gateway. To understand subnetting at the level required to install and
operate the SMX switcher, you must understand the concepts of a gateway, local
and remote devices, IP addresses and octets, and subnet masks and octets.
Gateways
The SMX switcher can communicate with the e-mail server that it 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 SMX switcher
” in chapter 5, “SMX Control Software,” and “
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
, which are separated by dots (periods) (figure A-5). Each octet can be
numbered from 000 through 255. Leading zeros, 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–5
—
IP address and octets
Subnet masks and octets
The subnet mask (figure A-6) is used to determine whether the local and
remote devices are on the same or different subnet. The subnet mask consists
of four numeric octets separated by dots. Each octet can be numbered from
000 through 255, up to 3 digits total per octet. Leading zeros are optional. 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–6
—
Subnet mask and octets
