1. [单选题]After working all night and successfully configuring a Cisco router for the Ezonexam network you save your changes on the startup config, reboot the router, and go out for a cigarette. When you return, none of your changes are active and the router boots to the initial configuration mode! Which of the choices below indicates the source of your problem?
A. Hardware failure in NVRAM prevents the router from loading the config
B. Startup-config in flash is corrupt and cannot be analyzed
C. Router configuration-register set to bypass startup configuration
D. Startup-config in NVRAM is corrupt and cannot be analyzed
E. None of the above
2. [单选题]The Ezonexam LAN is upgrading all devices to operate in full duplex. Which statement is true about full-duplex Ethernet in comparison to half-duplex Ethernet?
A. Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receive
B. Full-duplex Ethernet consists of a shared cable segment. Half-duplex Ethernet provides a point-to-point link
C. Full-duplex Ethernet can provide higher throughout than can half-duplex Ethernet of the same bandwidth
D. Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex ethernet uses a jam signal
E. None of the above
3. [多选题]Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two answer choices.)
A. Full-duplex Ethernet uses CSMA/CD to prevent collisions.
B. Half-duplex Ethernet uses a loopback circuit to detect collisions.
C. A full-duplex Ethernet card allows 20Mbps for data transmission.
D. Full-duplex Ethernet makes use of two pairs of wires for data.
E. An Ethernet hub can operate both half and full duplex simultaneously.
