Decision engine in service request rule policy

Hi, experts!

There is an action 'Route to decision engine', which I can choose while creating a rule in rule policy for service requests. The context is 'SERVICEREQUEST'. And I can't understand, what is this decision engine? In the action of the rule I need to specify the decision engine id, but I have no idea where I can configure it? Couldn't you write some explanations or link for documentation for these two questions please.

I work with SAP CRM EHP3, Patch level 5.

Thanks for help in advance.

Regards, Andrey.