Overview

This NQE addresses an issue with Juniper switches where the Layer 2 learning subsystem can fail during MAC table collection, preventing the retrieval of MAC table data. To solve this, an NQE verification check was created to detect when a switch experiences this error. The check automatically flags a violation, notifying the user when the error occurs. This allows the customer to quickly identify affected switches and take corrective action, such as rebooting the device, ensuring continuous network operation and reducing downtime.

Benefits:

• Proactive error detection: Automatically flags switches experiencing the Layer 2 learning subsystem error, enabling users to address issues before they impact network performance.
• Reduced downtime: Quickly identifies affected switches, allowing for immediate corrective action, such as rebooting, to restore normal operation and minimize disruptions.
• Streamlined network management: Automates the monitoring process, eliminating the need for manual checks and ensuring ongoing awareness of device health.

How it works

This query checks device state error responses against retrieval of the MAC table data from Juniper switches. This error indicates an issue with switching core processes that may require a switch reboot. 

foreach device in network.devices
where device.platform.vendor == Vendor.JUNIPER
foreach command in device.outputs.commands
where command.commandType == CommandType.MAC_TABLE
let violation = matches(command.response, "*error: the l2-learning subsystem is not responding to management requests*")
select {
violation,
device: device.name,
output: command.response
}