When you configure the ESXi SNMP agent for SNMPv3, the agent supports sending notifications (traps and informs) and receiving GET, GETBULK, and GETNEXT requests. SNMPv3 also provides stronger security than SNMPv1 or SNMPv2c, including key authentication and encryption.

Inform is a notification that the sender resends up to three times or until the receiver acknowledges the notification.