MuonCalibStreamInputSvc Node1 MuonCalibStreamInputSvc + MuonCalibStreamInputSvc() + ~MuonCalibStreamInputSvc() + nextEvent() + currentEvent() Node2 AthService - AthService() - AthService() - operator=() Node2->Node1 Node3 AthCommonMsg< Service > + msg() + msg() + msgLvl() Node3->Node2 Node4 Service Node4->Node3