There are no boot system commands in a router configuration in NVRAM.What is the fallback sequence that router will use to find an ios during reload?（）

单项选择题Which command shows your active Telnet connections?（）

A. show session
B. show cdp neighbors
C. show users
D. show queue

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?（）

A. 10
B. 40
C. 30
D. 20

单项选择题Which dose the frame-relay interface-dlci command configure?（）

A. remote DLCI on the main interface
B. local DLCI on the main interface
C. local DLCI on the subinterface
D. remote DLCI on the subinterface

单项选择题Which command can be a router to verify the layer 3 path to a host?（）

A. traceroute address
B. tracert address
C. ssh address
D. telnet address