Federates have regulation disabled by default. A federate utilizes the RTIambassador member function enableTimeRegulation() to request that the federate be acknowledged as a regulating federate. The Local RTI Component (LRC) calls the FederateAmbassador callback timeRegulationEnabled() to inform a federate that the enableTimeRegulation() request has been granted and informs the federate of its (possibly new) logical time.

Constrained
Constrained federates are those who subject themselves to the time-coordination will of regulating federates.

Federates have constrained disabled by default. A federate utilizes the RTIambassador member function enableTimeConstrained() to request that the federate be acknowledged as a constrained federate. The timeConstrainedEnabled() callback informs a federate that the enableTimeConstrained() request has been granted. It is possible to change the constrained policy dynamically. The RTIambassador method disableTimeConstrained() is the counterpart to enableTimeConstrained().

Look-Ahead Value
Amount of time specified by the regulating federate as a guarantee for the minimum amount of time that it will issue a time-stamped event ahead of a constrained federates existing local time.

Time-Stepped Federates
Time-stepped federates will calculate values based on a point in time and then process all events that occur up to the next point in time (current time + time step).

Event-Based Federates
Event-based federates will calculate values based on each event received from the federation execution. After an event is processed, the federate may need to send new events to the federation execution. This implies that the events may not happen on set time intervals but the times of events will be based on the time of the received events.

Optimistic Federates
Optimistic federates do not want to be constrained by the time advancement of regulating federates but instead will proceed ahead of LBTS to calculate and send events in the future. These federates will want to receive all of the events that have been sent in the federation execution regardless of the time-stamp ordering.