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Subnetting — a primer, Gateways, Local and remote devices – Extron Electronics MPX Plus 866 A Rev. B User Manual

Page 194: Ip addresses and octets, Subnet masks and octets, Preliminar y, Ethernet connection, cont’d

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Ethernet Connection, cont’d

MPX Plus 866 A Media Presentation Matrix Switcher • Ethernet Connection

A-6

PRELIMINAR

Y

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 network — a

set of IP devices that have portions of their IP addresses in common) is necessary in

order to understand the interaction of the switcher and the mail server gateway. To

understand subnetting at the level required to install and operate the switcher, you

must understand the concepts of a gateway, local and remote devices, IP addresses

and octets, and subnet masks and octets.

Gateways

The 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 values in the switcher (see “IP Settings/Options

window” in chapter 5, “Switcher Software”, and “System Settings page” in

chapter 6, “HTML Operation”).

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 three 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 three 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