Brocade SNMP Engine ID

Hi all

I am currently working on setting up SNMPv3 alerting on our Brocade SAN switches - after setting 
SNMP Informs Enabled to true i see there is an Engine ID field.

Is the Engine ID a unique identifier for each switch? Or can we use the same Engine ID for all switches? (type, model, FOS version, etc) - how do we know what to set the engine id to?

I can't seem to find much documentation online on how to configure this engine ID so any help or insight will be appreciated.

thanks!
Farhad