If this object and the mgmdRouterInterfaceImmedtLeave object are set to 'true' and the mgmdRouterInterfaceQryBefImmdLv object is set to 'false', then the router tracks the set of hosts that have membership of each (*,G) or (S,G). The router will only leave immediately if there are no hosts remaining. If mgmdRouterInterfaceImmedtLeave is also set to 'true', then the router will only leave immediately if there are no hosts remaining. Explicit host tracking is only performed if all hosts are IGMPv3/MLDv2 or IGMPv2/MLDv1. Note that tracking will only operate correctly in the presence of IGMPv2/MLDv1 hosts if they do not suppress Reports. If this field is changed from 'true' to 'false' then all host state on the interface will be removed. If this field is changed from 'false' to 'true' then host state will be created as membership reports are received. Until full state has been learnt it is possible that there could be hosts on the interface that the router does not yet have state for, and so a leave request could result in forwarding state being removed immediately.