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Why does my Cisco System Health sensor report out of threshold voltages?



When monitoring currents and voltages on my Nexus 7000 switch with the SNMP Cisco System Health sensor, particular channels of this sensor show an error status. PRTG encounters that these channels are below the error limit (the monitored value is zero) and sets the whole sensor into a down status.

cisco error n7k nexus-7000-series prtg system-health system-health-currents threshold

Created on Jan 8, 2014 3:34:55 PM by  Gerald Schoch [Paessler Support]

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This article applies to PRTG Network Monitor 13.4.8 or later

Cisco System Health Voltage: Low Threshold Error

If you encounter low threshold voltage warnings because of 0.00 voltage measured in a channel when monitoring switches of the Nexus 7000 series and, thus, the corresponding SNMP Cisco System Health sensor goes into Down status, the reason might be a bug in NX-OS, the network operating system of Cisco’s Nexus-series switches.

When monitoring the N7K, this bug results in an incorrect alert due to a low threshold warning. According to Cisco’s bug report, this only occurs with a certain transceiver type (CISCO-FINISAR) when the low threshold is 0.00 Volts.

Please see Cisco’s bug details here.


Unfortunately, there is not really a workaround for this issue. In order to avoid the incorrect alerts in PRTG, please disable the error limit manually.

  1. Open the Settings of the affected channel.
  2. Choose Disable Limits in section Limits.

You can alternatively remove the affected interface from monitoring. Furthermore, remove the SNMP voltage threshold trap from your N7K device.

Created on Jan 8, 2014 3:37:39 PM by  Gerald Schoch [Paessler Support]

Last change on Jan 8, 2014 4:40:07 PM by  Gerald Schoch [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.