Rockwell Automation Ethernet Design Considerations Reference Manual - Manual (Page 15)

Rockwell Automation Publication ENET-RM002C-EN-P - May 2013 15
EtherNet/IP Overview Chapter 1
Configuration Requirements All devices on Ethernet communicate by using the Ethernet address for the
device. This address is sometimes referred to as the hardware address or Media
Access Controller (MAC) address. The hardware address is a unique, six-byte
address, which is embedded in the circuitry of every device on an Ethernet
network. Every vendor of Ethernet products obtains their own unique address
range.
For a device to communicate on an Ethernet network, you must configure its
IP address, gateway address, and subnet mask.
IP Address
The IP address identifies each node on the IP network or system of connected
networks. Each TCP/IP node on a network must have a unique IP address. The
IP address is 32 bits long and has a network ID part and a host ID part. Because
networks vary in size, there are four types of networks.
The network class determines how an IP address is formatted.
Network Type Application
Class A Large networks with many devices
Class B Medium-sized networks
Class C Small networks (fewer than 256 devices)
Most common for private, industrial networks
Class D Multicast addresses
Class A
Class B
Class C
Network (7 bits)
Network (14 bits)
Network (21 bits) Local Address (8 bits)
Local Address (16 bits)
Local Address (24 bits)
Class D Multicast Address (28 bits)
0
0
8
8
8
8
0
0
0
16
16
16
24
24
24
31
31
31
31
1 0
1 0 1
1 1 1 0
16 24