Troubleshooting guide

TD 92735EN
15 May 2012 / Ver. G
Installation and Operation Manual
Unite Connectivity Manager
207
Appendix D: Network Monitoring in a Redundancy System
In a redundant system, both the primary Unite CM and the secondary Unite CM can check if
they have connection to the network by sending ICMP inquiries to an optional equipment in
the same network. It is recommended to use the equipment that is centrally installed in the
network, for example an IP-PBX. See the example below for more information.
If the active Unite CM loses the connection to the network, the standby Unite CM will
become active instead.
Figure 94. Illustration of using a centralized equipment as network reference
In figure 90, both the primary Unite CM and the secondary Unite CM are using the IP-PBX as
network reference since it is centrally installed in the network.
NOTE: The use of the network monitor function is optional
1
, but it is strongly recommended
to use when the modules are connected to different switches. If the function is
disabled and the modules cannot communicate with each other, both modules might
become active since they consider that the other module has failed. The result is that
the one part of the system will write data to the primary Unite CM, and the other part
will write data to the secondary Unite CM. This behaviour is called “split brain
behaviour”.
1.By setting the Network monitor IP address to 127.0.0.1 disables the function.
Primary Unite CM
Base Station
IP-PBX
Secondary Unite CM
Switch Switch