Specifications

Niagara Release 2.3
Revised: May 22, 2002 Niagara Networking & Connectivity Guide
Chapter 3 Connecting on a LAN
Niagara Considerations
3–2
The Web Supervisor, on the other hand, has a public IP address assigned to it in the
firewall. It can be reached by the BUI user located across the Internet (the external
user) and also the internal BUI user. In this scenario, the Web Supervisor has been
engineered to include GxPages showing real-time information originating from the
JACEs. To accomplish this, the Niagara hosts use station-to-station (interstation)
links. In addition, the Web Supervisor functions as a supervisory station, archiving
other stations’ data logs, alarms, etc. This data is available to either BUI user.
The network site administrator chose to place the Web Supervisor outside the
enterprise LAN but just behind the firewall. This allows faster access by the external
BUI user because the network traffic between the external host and the Web
Supervisor does not come onto the customer’s enterprise LAN (which may be
congested).
Figure 3-1 Typical single site (LAN) architecture.
Router
JACE-5
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JACE-NP
Ethernet Hub or Switch
BUI
Field Controllers
Ethernet Hub or Switch
Browser User Interface (BUI)
Field Controllers
Internet
Firewall with Proxy
and NAT
Web Supervisor
External IP Address:
204.253.56.14
Inside IP Address:
192.168.125.3
NAT Addresses: 204.253.56.x
Network: 192.168.125.0
Subnet Mask: 255.255.255.1
Ethernet Hub or Switch
ABC Company
Router
Network: 192.168.1.0
Subnet Mask: 255.255.255.0
IP Address: 192.168.1.120
Subnet Mask: 255.255.255.0
IP Address: 192.168.1.125
Subnet Mask: 255.255.255.0
IP Address: DHCP assigned
Subnet Mask: 255.255.255.0