User manual

220 Publication ENET-UM001I-EN-P - January 2010
Appendix D EtherNet/IP Network 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 intege
rs (0...255) separated by periods
where each integer gives the value of one byte of the IP address.
For example, the 32-bit IP address:
10000010 00000000 00000000 00000001 is written as 130.0.0.1.
Gateways
A gateway connects individual physical networks into a system of networks.
When a node needs to communicate with a node on another network, a
gateway transfers the data between the two networks. The following figure
shows gateway G connecting Network 1 with Network 2.
When host B with IP address 128.2.0.1 communicates
with host C, it knows
from C’s IP address that C is on the same network. In an Ethernet
environment, B can then resolve C’s IP address to a MAC address and
communicate with C directly.
IP Address Class
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
128.1.0.1
128.2.0.1 128.2.0.2
128.2.0.3
128.1.0.2
A
B
C
G
Network 1
Network 2