SNMP trap vs inform
The SNMP Inform Request feature supports sending inform requests. SNMP asynchronous notifications are usually sent as SNMP traps. Traps are less reliable than informs because an acknowledgment is not sent from the receiving end when a trap is received; however, an SNMP manager that receives an inform acknowledges the message with an SNMP response PDU. If the sender does not receive a response for an inform, the inform can be sent again.
Informs and traps can be configured for SNMPv1, v2, and v3.
Links:
https://forum.networklessons.com/t/how-to-configure-snmpv3-on-cisco-ios-router/1033/31?u=lagapides
https://forum.networklessons.com/t/how-to-configure-snmpv3-on-cisco-ios-router/1033/57?u=lagapides