3-4Configure the Adapter for Your EtherNet/IP Network

IP addresses are written as four decimal integers (0 to 255) separated by periods where each integer gives the value of one byte of the IP address.

EXAMPLE

For example, the 32-bit IP address:

10000000 00000001 00000000 00000001 is written as 128.1.0.1

Gateway Address

This section applies to multi-network systems. If you have a single network system, refer to the next section.

The Gateway Address is the default address of a network. It provides a single domain name and point of entry to the site. Gateways connect 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 figure shows gateway G connecting Network 1 with Network 2.

A

128.1.0.1

Network 1

128.1.0.2

G

B

128.2.0.1

C

128.2.0.2

128.2.0.3

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 into a hardware address (MAC address) and communicate with C directly.

When host B communicates with host A, it knows from A’s IP address that A is on another network (the net IDs are different). In order to send data to A, B must have the IP address of the gateway connecting the two networks. In this example, the gateway’s IP address on Network 2 is 128.2.0.3.

Publication 1734-UM011C-EN-P - January 2006

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Bradley Smoker 1734-AENT manual Gateway Address