单项选择题
Which commands is necessary to permit SSH or Telnet access to a cisco switch that is otherwise configured for these vty line protocols?（）
A. transport type all B. transport output all C. transport preferred all D. transport input all
单项选择题 What is the OSPF default frequency,in seconds,at which a cisco router sends hello packets on a multi-access network?（）
单项选择题 Which dose the frame-relay interface-dlci command configure?（）
单项选择题 Which command can be a router to verify the layer 3 path to a host?（）
