问答题 WhichOSPFnetworktypeisidealforpartiallymeshedNBMAnetworksbecauseitiseasytoconfigure（requiresnoconfigurationofneighborcommands），consumesonlyoneIPsubnet，andrequiresnodesignatedrouterelection？
问答题 WhichOSPFfeatureallowsaroutertocontinuetoforwardpacketswhileundergoingspecific，well-knownfailureconditions？
问答题 WhyareRegistermessagesneededinPIMSM？