Overlapping IP Address Ranges
IMPORTANT:
Overlapping IP address ranges only applies when the controller operates in Dual-IP mode.
The IP address and subnet mask values that you assign to an Ethernet port establish an IP address range for the port. The subnet mask value is used to establish the network part of the IP address.
Overlapping IP address ranges occurs when any IP address from one range is also present in the other IP address range. When a controller uses Dual-IP mode, the network parts cannot overlap between the Ethernet ports.
The following examples describe conditions in which IP address ranges that overlap or do not overlap.
IMPORTANT:
With
ControlLogix®
5590 controllers, the Ethernet ports on the controller itself are labeled 1 and 2. In programming and communication software, the ports are described as A1 and A2.The key difference between the port configurations in the examples is the Subnet Mask/Network Mask value for port 1. In the first example, the value is 255.255.255.0. In the second example, the value 255.255.252.0.
Example - IP Address Ranges That Do Not Overlap
The following table describes port 1 and port 2 configurations that use IP address ranges that do not overlap.
None of the IP addresses in either port's address range exists in the IP address range for the other port.
Port Number | IP Address | Subnet Mask/Network Mask | IP Address Range (Low to High) |
|---|---|---|---|
1 | 192.168.1.5 | 255.255.255.0 | 192.168.1.1…192.168.1.254 |
2 | 192.168.2.1 | 255.255.255.0 | 192.168.2.1…192.168.2.254 |
Example - IP Address Ranges That Do Overlap
The table describes port 1 and port 2 configurations that use IP address ranges that do overlap.
All IP addresses in the port 2 address range are in the port 1 address range.
Port Number | IP Address | Subnet Mask/Network Mask | IP Address Range (Low to High) |
|---|---|---|---|
1 | 192.168.1.5 | 255.255.252.0 | 192.168.0.1…192.168.3.254 |
2 | 192.168.2.1 | 255.255.255.0 | 192.168.2.1…192.168.2.254 |
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