User manual

Publication ENET-UM001I-EN-P - January 2010 217
Appendix D
EtherNet/IP Network Overview
Introduction
This appendix defines some basic Ethernet network concepts and how the
EtherNet/IP protocol is used for control.
Ethernet Protocols
On the most basic level, Ethernet is a wire or cable that connects computers
and peripheral modules so that they can communicate. The actual wire used
for the network is referred to as the network medium. Beyond the physical
medium, all Ethernet networks support protocols that provide sophisticated
data transfer and network management capability.
Topic Page
Ethernet Protocols 217
Configuration Requirements 219
Manual Configuration on an Ethernet Switch 222
Change Ports on an Ethernet Switch 222
Additional Resources 222
Protocol Descriptions
Protocol Description
Transmission control
protocol/internet protoc
ol
(TCP/IP)
TCP/IP is a transport-layer protocol (TCP) and a network-layer protocol (IP) commonly used in business
environments for c
ommunication within networks and across internetworks. The EtherNet/IP
communication modules use TCP/IP for explicit messaging, that is, messages in which time is not a
critical factor, such as uploading or downloading programs.
User datagram
protocol/Internet proto
c
ol
(UDP/IP)
UDP is a much simpler transport protocol. It is connec
tionless and provides a simple means of sending
datagrams between two modules. UDP is used by applications that implement their own handshaking
between modules and only require minimal transport service. UDP is smaller, simpler, and faster than
TCP and can operate in unicast, multicast, or broadcast mode. The EtherNet/IP communication modules
use UDP/IP for real time I/O messaging.
CIP CIP applies a common application layer over an Ethernet network by encapsulating messages in
TCP/UDP/IP
. This common application layer
is the control and information protocol (CIP), which provides
interoperability and interchangeability of industrial automation and control modules on an Ethernet
network. EtherNet/IP supports both real-time I/O (implicit messaging) and explicit messaging.
See the EtherNet/IP Performance and Application Guide, publication ENET-AP001, for more information
on EtherNet/IP
.