Error control, what is it and why should you enable it?
Error control (EC) is the Quantellium program logic that tries to find the root-cause of a problem in case a device doesn’t respond to status requests anymore. EC helps keeping the “false positive” rate, and thus the number of alerts generated, to an absolute minimum!
EC tries, in case of a non responding device, to find out whether the problem is caused by a failure of the device itself OR by another device in the chain of devices (network paths) between the Quantellium host and the problem device! EC logic is based on the following information:
- Does a device switch or route traffic?
- To what other device(s) is a device connected? Who are its directly connected neighbors?
- Which station (host) runs Quantellium?
Error Control – disabled
The picture above shows the situation shortly after a failure of switch04-e. Not only switch04-e gets the “down” status but also all devices “behind” this switch are tagged “down”. 10 alerts are generated. 10 eMails or SMS messages are sent from which 90% is a “false positive”!
Error Control – enabled
Now, EC is enabled. Only switch04-e has the “down” status. Only 1 alert is generated and only 1 alert eMail or SMS message is sent!
The small “Q” below device “Cerium” indicates the host that runs Quantellium. Because switch04-e is “down”, Quantellium is unable to determine the status of the devices “behind” it. A blue tag on a device indicates “Status unknown”. EC supports multi-homing and redundant network paths provided that the network maps represent the actual situation.
How to enable Error Control
Enabling EC only takes the following steps:
- Add a device representing the host or server that runs Quantellium to a map.
- Open the Administration | Various system settings page and scroll to the Connection Utilization Coding (CUC) & Error Control (EC) pane.
- Use the control labelled “On which…” to select the Quantellium host and click the [Apply] button. A small “Q” (grayed out meaning inactive) icon appears below the device icon on the map.
- Verify the Switching/Routing settings of the classes used in your project!
- Add connections between devices conforming the actual situation. Adding connections that factually don’t exist, will not work.
- Within 100 seconds after you added the last connection, the small grayed out “Q” icon should become colored meaning that EC is activated.
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