1. Refer to the exhibit. Router R1, the DCE device, has just
been configured for PPP encapsulation with authentication. What series of
commands will allow another router, the DTE device, to communicate over its
serial 0/0/0 interface to router R1?
Router(config)# hostname R3
R3(config)# username R1 password Cisco
R3(config)# interface Serial 0/0/0
R3(config-if)# encapsulation ppp
R3(config-if)# ip address 172.16.3.3 255.255.255.0
R3(config-if)# ppp authentication chap
2. Which serial communications DTE/DCE interface standard is
used to provide high-speed connectivity of up to 52 Mbps between LANs and is
found on many high-end Cisco routers?
EIA/TIA-612/613 (HSSI)
3. Which three statements are true regarding LCP? (Choose
three.)
It is responsible for negotiating link establishment.
It terminates the link upon user request or the expiration
of an inactivity timer.
It can test the link to determine if link quality is
sufficient to bring up the link.
4. Refer to the exhibit. On the basis of the show interface
Serial0/0 output, how many NCP sessions have been established?
Two
5. Which two statements are true about time-division
multiplexing (TDM)? (Choose two.)
Multiple channels can transmit over a single link.
Original data streams must be reconstructed at the
destination.
6. Which authentication protocol can be spoofed to allow
playback attacks?
PAP
7. Refer to the exhibit. What can be concluded about the
function of the Serial 0/0/0 interface on the router after the commands are entered?
The serial link will be closed if the number of received
packets at the destination node falls below 90 percent of the packets that are
sent.
8. Which three statements are correct about HDLC
encapsulation? (Choose three.)
HDLC implementation in Cisco routers is proprietary.
HDLC is the default serial interface encapsulation on Cisco
routers.
HDLC uses frame delimiters to mark the beginnings and ends
of frames.
9. What function do Network Control Protocols provide for a
PPP connection?
To allow multiple Layer 3 protocols to operate over the same
physical link
10. What advantage does PPP have over HDLC for serial
communications?
It supports authentication
11. Refer to the exhibit. What statement is true regarding
the output shown?
Data is able to flow across this link.
12. Refer to the exhibit. What statement is true regarding
the output shown?
One router has suggested PAP authentication, and the other
has accepted authentication but suggested CHAP authentication.
13. Which three statements correctly describe PPP
authentication? (Choose three.)
PAP sends passwords in clear text.
CHAP uses a challenge/response that is based on the MD5 hash
algorithm.
CHAP uses repeated challenges for verification.
14. Refer to the exhibit. While troubleshooting a serial
interface, a technician enters the command show interface serial 0/0/0 . If the
interface is in DCE mode, what two problems are likely to cause the indicated
problem? (Choose two.)
The remote CSU or DSU has failed.
A timing problem has occurred on the cable.
15. Why are serial connections preferred over parallel
connections for long transmission lengths?
Parallel connections are subject to clock skew and to
crosstalk between wires.
16. Refer to the exhibit. Which two statements are true
regarding the output shown? (Choose two.)
The router has agreed on IP parameters.
The router has negotiated LCP successfully.
17. What does the demarcation point represent in data
communication physical circuits?
Physical point at which the public network ends and the
private customer network begins
18. Refer to the exhibit. Which statement is true about PPP
operation?
Both the link-establishment and network-layer phase
completed successfully.
19. Which two options can LCP negotiate? (Choose two.)
Link quality
Authentication
20. Which PPP configuration option can be used to establish
load balancing over the interfaces of a router?
Multilink
21. Refer to the exhibit. Router R1 is not able to
communicate with a neighbor router that is directly connected to serial 0/0/0.
What is the reason for this?
The interface has been administratively shutdown with the
shutdown command.
CCNA 4 Chapter 2 Answers |
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