单项选择题
A.Log
B.Log-input
C.Log-output
D.Logging
单项选择题 Whiledeployinganewswitch，youaccidentlyconnectports3/12and3/18together，creatingaloop.STPdetecteditandplacedport3/18inblockingmode.WhydidSTPnotplaceport3/12inblockingmodeinstead？（）
问答题 第二条rate-limit的作用是什么？
单项选择题 Youdeployednewfibersinyournetworktoreplacecopperspansthatweretoolong.Whilereconnectingthenetwork，youexperiencednetworkproblemsbecauseyoureconnectedwrongfiberstowrongports.Whatcouldyoudotopreventthistypeofprobleminthefuture，particularlywhenconnectingandreconnectingfiberpairs？（）