单项选择题
A.The hello dead timer expires.
B.The restart duration timer expires.
C.The restarting router sets the down bit.
D.The restart helper sends out three CSNPs.
单项选择题 WhatisthemaximummetricvaluethatcanbereportedinanarrowmetricTLV？（）
单项选择题 AccordingtoJUNOSsoftwarerouteselectionalgorithm，whichIS-ISroutetypeismostpreferred？（）
单项选择题 AnIS-ISrouterisadjacenttoandpassingtrafficwithaneighbor.Youperformashowis interfacedetailcommandandnoticethatforsomeinterfacesyouhaveacircuittypeof3.WhichIS-ISlevel（s）isenabledontheseinterfaces？（）