Issue
During extremely high levels of network traffic Ethernet controllers are going offline.
Product Line
Andover Continuum
Environment
The following controller versions and above:
- bCX1 Firmware V4.500065
- bCX1-INF Firmware V1.200021
- Netcontroller CX9900 V1.530026
- Netcontroller II V2.100027
- ACX57xx V1.100027
Cause
Although the above firmware versions (and higher) all contain a fix to stop the controllers resetting due to excessive traffic levels in a broadcast storm (LAN Errors), they can still be seen to go offline even though they no longer reset and lose their data.
Resolution
If a controller detects a broadcast storm and receive excessive data traffic that fills up its buffers, then the controller may turn off their receiver to protect themselves and ensure that they do not reset.
By doing this it allows the controller to continue controlling and running PE programs as well as retaining the data in the RAM memory.
When the storm stops or data traffic levels reduce enough for normal communication to continue, then the controllers will come back online and communicate again to the Workstations and other Ethernet level controllers.
Note: A broadcast storm can be generated by incorrect BBMD configuration, i.e. more than 1 device set as a BBMD in one subnet can cause a storm to occur.
