Specifications

Niagara Release 2.3
Niagara Networking & Connectivity Guide
GL-8
Glossary
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null modem cable A null modem cable is like a modem cable but is specially designed to hook two
computers together, rather than a computer and a modem. The cable attaches to male
serial (RS-232) ports on each computer.
O
OS Operating system. It is the base program installed on a computer. It is used to run
other programs, and is responsible for basic functions of the computer such as
accepting keyboard input, keeping track of files on the hard disk, and controlling
peripheral devices.
P
packet In IP networks, a packet contains a small bit of data along with information about the
source and destination IP addresses of the hosts sending and receiving the data.
Typically, many packets make up the complete data transmission from one host to
another. Packets are also known as datagrams.
patch cable An Ethernet cable used to connect a host and a hub.
platform Refers to the underlying hardware or software of a system. In this document, it is
most often used to differentiate between the models of controllers based on operating
system (the JACE-4/5 platform versus the JACE-NP platform). In some instances, it
is used to differentiate between two models within the OS group (Embedded NT
platform versus the Full NT platform).
port In TCP/IP networking, ports are used for long term conversations between two hosts
(such as a client accessing a web page on a server). A port is a communication
channel that allows different applications (such as FTP, HTTP, and SMTP) on the
same computer to use network resources without interfering with each other.
private IP address A range of IP numbers set aside by the designers of the Internet for use in private
networks. They allow organizations to implement IP addressing without having to
apply to an ISP for unique global (public) IP addresses for every host. Hosts using
these private addresses cannot be reached directly from the Internet (nor can they
communicate to the Internet). See also public IP address.
protocol A set of standards that define how computers (or processes) talk to one another. In
order for the computers to talk, both must implement the same protocol.
proxy server A device usually implemented to provide connection sharing at a company. This
means the company can have fewer public IP addresses used by many more hosts
with private IP addresses. See also application proxy.