vmwVpxdOldStatus and vmwVpxdNewStatus are shown as "Unset" in SNMP traps for certain vCenter Server alarms

Products

• VMware vCenter Server

Issue/Introduction

• You see notification types of vmwVpxdOldStatus and vmwVpxdNewStatus that are set as "Unset" in the SNMP trap which was sent from vCenter Server.
  Example of an SNMP trap received from vCenter Server:

enterprise:        .1.3.6.1.4.1.6876.4.3
generic-trap:      6
specific-trap:     203
UpTime:    #########
Uptime:    ## days, ##:##:##.##
community: public
IPaddress: ###.###.###.###
PeerIPaddress:     ###.###.###.###
ReceivedPort:      162
ReceivedTime:      #########
Protocol:  UDP
SNMP_Version:      1
iso.org.dod.internet.private.enterprises.vmware.vmwProductSpecific.vmwVC.vmwVpxdTargetObjType.0:       4
iso.org.dod.internet.private.enterprises.vmware.vmwProductSpecific.vmwVC.vmwVpxdOldStatus.0:       Unset
iso.org.dod.internet.private.enterprises.vmware.vmwProductSpecific.vmwVC.vmwVpxdNewStatus.0:       Unset

Environment

vCenter Server 7.x
vCenter Server 8.x

Cause

vCenter Server has preconfigured vSphere alarms, some of which are called stateless alarms.
These alarms do not store data, calculate status, or display their status.
Due to the nature of the stateless alarm, vmwVpxdOldStatus and vmwVpxdNewStatus are set as "Unset" by vCenter Server.

Resolution

This is expected behavior as the alarm is stateless.

Additional Information

Preconfigured vSphere Alarms