Rockwell Automation 1761-NET-ENIW MicroLogix Ethernet Interface (ENI) User Manual - Manual (Page 136)

Publication 1761-UM006E-EN-P - August 2005
Glossary 2
IP (Internet Protocol)
IP specifies the format of packets and the addressing scheme. Most
networks combine IP with a higher-level protocol called Transport
Control Protocol (TCP), which establishes a virtual connection
between a destination and a source.
IP by itself is something like the postal system. It allows you to
address a package and drop it in the system, but there's no direct link
between you and the recipient. TCP/IP, on the other hand, establishes
a connection between two hosts so that they can send messages back
and forth for a period of time.
IP Address
A 32-bit address assigned to hosts that want to participate in a TCP/IP
internet. IP addresses are the abstraction of physical hardware
addresses, with a network and host partition which makes routing
efficient.
NetLinx Services
The NetLinx services occur over the well-known port 0xAF12 and
define a connection protocol that exists after a TCP/IP connection is
established. It also defines a set of services and packet formats to
support the protocol.
Network
A series of stations (nodes) connected by some type of
communication medium. A network may be made up of a single link
or multiple links.
Node
Also called a station. An address or software location on the network.
MTA (Mail Transfer Agent)
The software function responsible for delivering outgoing mail to its
final destination.
PCCC (Programmable Controller Communications Commands)
RS-232
An EIA standard that specifies electrical, mechanical, and functional
characteristics for serial binary communication circuits.