Hi [NAME],   Unfortunately, N3000 series are not fully supported in OME, reference OME support matrix for switches: [URL]   I've also checked the catalog file that OME uses for firmware comparison and updates, the switches are not listed, hence that is why OME will show unknown after a few moments.   I'm unable to find any info if the switches will be added into the supported list in the next updates, but it would be good that you can contact the support line to raise a feature request.
 I'm having trouble getting some Dell network switches to be detected properly in OME.  Since they're network switches, monitoring is done with SNMP.  I've created the Community String on the switch, and initial Discovery goes fine in OME.  However, within a few hours usually, the switch's Health Status changes to Unknown.  If I force a new Discovery, they'll be found and the health changes to OK, only go back to Unknown within a few hours. I have this occurring on over a dozen switches.  All are Dell (EMC) Networking N3024 switches, firmware is a mix of 6.2.6.6 and 6.5.4.18.  I also have a Dell EMN Networking N3018EP-ON and Dell EMC Networking N3024ET-ON, both at firmware 6.5.2.35, which are always detected fine in OME.  As far as I can tell, all switches' SNMP configuration is identical 9except for the Local Engine ID, of course). Any suggestions would be appreciated.  
OME Monitoring - Network Switches