There may be a situation where a higher level interface (l2vlan in this case), is set to generate port status alarms however the alarm is being suppressed on this interface. Below is an explanation as to why this happens.
In the scenario below, the Gi0/0.1 interface is a part of a Global Collection of which Spectrum Policy Manager is setting a Live Pipes policy. Users may expect the suppressed interface to alarm.
Release : All
Component : Spectrum Alarm & Event Management
In this case, the Sim33112_Gi0/0 interface was also down. Due to this, fault isolation was run and the Sim33112_Gi0/0.1 was placed into a suppressed state.
The Sim33112_Gi0/0 is not in the "Interfaces for Monitoring" Global Collection, therefore no alarm was generated on this interface either even though this was the true root cause.
If the physical interface also has the "generatePortStatusAlarms" set to true, then users will see the following:
When a monitored higher layer port goes down (l2vlan in this case), Spectrum will query the statuses of all lower layer interfaces before any alarms are generated. If the lower layer interface is down, then Spectrum will suppress the higher layer interface alarm. This behavior is outlined in the docs linked below: