ByteStreamInputSvc Node1 ByteStreamInputSvc + ByteStreamInputSvc() + ~ByteStreamInputSvc() + nextEvent() + previousEvent() + setEvent() + currentEvent() + currentEventStatus() + getBlockIterator() + closeBlockIterator() + ready() + generateDataHeader() + positionInBlock() + validateEvent() + interfaceID() Node2 AthService - AthService() - AthService() - operator=() Node2->Node1 Node3 AthCommonMsg< Service > + msg() + msg() + msgLvl() Node3->Node2 Node4 Service Node4->Node3