The vCenter Server Appliance includes an SNMP agent that can send trap notifications and receive GET, GETBULK, and GETNEXT requests.
You can use the appliance shell API commands to enable and configure the vCenter Server Appliance SNMP agent. You configure the agent differently depending on whether you want to use SNMP v1/v2c or SNMP v3.
In vSphere 6.0 SNMP v3 informs are not supported. The vCenter Server Appliance supports only notifications such as v1 and v2c traps, as well as v3 traps with all security levels.