Rockwell Automation Ethernet Design Considerations Reference Manual User Manual
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Rockwell Automation Publication ENET-RM002C-EN-P - May 2013
Chapter 1
EtherNet/IP Overview
Each node on the same physical network must have an IP address of the same
class and must have the same network ID. Each node on the same network must
have a different local address (host ID), thus giving it a unique IP address.
IP addresses are written as four-decimal integers (0...255) separated by periods
where each integer gives the value of one byte of the IP address.
For example, the following 32-bit IP address is written as 130.0.0.1:
10000010 00000000 00000000 00000001
Public IP addresses are for computers and devices connected to the Internet.
Devices on industrial networks are not connected to the Internet, but they
communicate with each other over an EtherNet/IP network. These devices use
private IP addresses that are not routed on the Internet.
Private IP addresses typically start with 10, 172, or 192 as the first part of the
address. Private IP addresses are typically connected to the Internet through a
Network Address Translation (NAT) device.
For more information about NAT, see
Class
Leftmost Bits
Start Address
Finish Address
A
0xxx
0.0.0.
127.255.255.255
B
10xx
128.0.0.0
191.255.255.255
C
110x
192.0.0.0
223.255.255.255
D
1110
224.0.0.0
239.255.255.255