Lan Redundancy; Ip Addresses - GE D20MX Instruction Manual

CHAPTER 3: CONNECTING TO DEVICES AND NETWORKS

LAN redundancy

IP addresses

D20MX INSTRUCTION MANUAL
Both twisted-pair and fiber optic Ethernet options provide two LAN redundancy schemes
called redundant LAN and dual LAN.
The redundant LAN scheme provides automated fail over between two Ethernet network
connections (TX1/RX1 and TX2/RX2) that share a single MAC address.
When the primary port (that is, port 1) receives no signal, or detects a fault signal from the
remote link partner, the D20MX switches to the secondary port (that is, port 2) if it has a
valid link. The D20MX reverts to the primary port if the primary link is restored or no signal
is present on the secondary port.
With the dual LAN scheme, each port has a unique MAC, IP address and subnet. Each
remote device participating in a dual LAN scheme must have a primary IP address
reachable through the LAN A subnet of the D20MX and a secondary IP address reachable
through the LAN B subnet of the D20MX. D20MX client applications fail over to the remote
device's secondary IP address when they detect a failure to communicate with the remote
device's primary IP address. D20MX server applications accept communications from the
remote device's primary or secondary IP address.
To configure a system for redundant LAN operation, enable only LAN A in the device
properties of the D20MX. To configure a system for redundant LAN operation with an Alias
IP, enable both LAN A and LAN B in the device properties of the D20MX and set the
"Redundancy" field in the B119-1N LAN Redundancy Manager > LRM Configuration table
to "Redundant LAN". An Alias IP allows the D20MX to communicate with devices using the
dual LAN scheme and devices using the redundant LAN scheme, simultaneously.
To configure a system for dual LAN operation, enable both LAN A and LAN B in the device
properties of the D20MX and set the "Redundancy" field in B119-1N LAN Redundancy
Manager > LRM Configuration table to "Dual LAN". The D20MX device properties and the
B119-1N LAN Redundancy Manager configuration may be configured through SGConfig
8.1 and higher.
The D20MX assigns IP configuration to its LAN A and optionally LAN B interface according
to the rules defined in Table 17.
In a standalone system, the D20MX assigns the LAN A and LAN B IP addresses exactly as
you configured them in SGConfig.
In a redundant system, the D20MX assigns the LAN A and LAN B IP addresses of the Active
CCU exactly as you configured them in SGConfig.
However, in other modes, the CCU assigns derived IP addresses as indicated in Table 17.
For a description of the modes, refer to Table 19. The D20MX assigns the subnet mask of
the derived IP addresses as the subnet mask configured in the LAN A or LAN B
configuration.
Table 17: D20MX IP address assignment
CCU Redundant Mode
System
CCU A Standalone Active, Debug
or Disabled
CCU A Redundant Active
CCU B Redundant Active
LAN A IP Configuration
IP Address: LAN A IP
Address
Mask: LAN B Subnet Mask
(e.g 192.168.1.1 /
255.255.255.0)
GE INFORMATION
LAN B IP Configuration (If
Configured)
IP Address: LAN B IP
Address
Mask: Configured LAN B
Subnet Mask (e.g.
192.168.2.1 / 255.255.255.0)
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