Sample Network with RFC 1577 Configuration
device on the ATM network, maintains the Logical IP Subnetwork (LIS) as explained in the CIP over ATM section of Chapter 4.
Ethernet traffic for Broadmore 1750 #1 goes through the gateway directly to Broadmore 1750 #1. Ethernet traffic for Broadmore 1750 #2 and Broadmore 1750 #3 is routed by the gateway to Broadmore 1750 #1. The server uses LIS data to convert the IP address to an ATM address; the traffic is then sent over the ATM to the destination Broadmore 1750 where it is interpreted and acted upon as required.
Broadmore 1750 #2 has no Ethernet connection and its gateway is set to null. This Broadmore 1750 sends all Ethernet traffic over the ATM (to Broadmore 1750 #1) by default. Broadmore 1750 #1 then forwards the traffic to the gateway and ultimately to the appropriate Ethernet address.
Broadmore 1750 #3 has an Ethernet gateway (local control station in example diagram on next page). However, traffic to the master control station will not be delivered since the local control station has no Ethernet route to the master control station. A static route is added to Broadmore 1750 #3. This static route sends the response to all traffic from the master control station back to it via a static route using LIS conversion.
This use of CIP over ATM provides inband control of remote Broadmore 1750s. After initial setup, this configuration is essentially transparent to the master control station.
The master control station addresses:
Broadmore 1750 #1 by IP address,
Broadmore 1750 #2 by CIP address,
Broadmore 1750 #3 by CIP address.
Broadmore 1750 - Release 4.6 |
