江浙沪招生考试网

1. A router is set to boot from flash, but cannot find boot commands in the configuration. Also, valid files do not
exist in the default flash device. The router will:
A. Boot from ROM, since there are no valid sources
B. Try to boot from the network, using a default filename
C. Terminate the boot process with an error message
D. Try to boot from the network, then boot from ROM as a backup
Answer: D 
2. A network administrator is using debug commands to check the performance of a network. What steps can the
administrator take to ensure that the "debug" will not require too much CPU, or at least that she will not have to
reboot the router to disable debug? (multiple answer)
A. Make the debug command as specific as possible
B. Use the max-time parameter of the debug command
C. In configuration mode, enter scheduler interval 15
D. Configure a loopback to channel debug traffic
Answer: AC 
3. If there are two different headends with two different frequencies available sharing the same plant, what
frequency will the two groups of cable modems, which are brand new, and have never been on-line, lock on?
A. They will lock on the frequency configured on the linecard.
B. They will lock on the frequency configured on the upconverter.
C. They will lock on the first frequency they find.
D. They will lock on the lowest frequency.
E. They will lock on the last frequency remembered in ram.
Answer: C 
4. Which are HFC cable television forward path networks aligned to provide? (multiple answer)
A. For asymmetrical gain since the downstream and upstream bandwidths are also asymmetrical
B. For unity gain with a fixed input level and varying output levels adjusted by the selection of a fixed value
attenuator and equalizer at the output stage in each of the forward amplifiers in the network
C. For unity gain with a fixed output level and varying input levels adjusted by the selection of a fixed value
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attenuator & equalizer at the input stage of each of the forward amplifiers in the network
D. It is not necessary to align the forward path amplifiers since the CMTS will automatically compensate for
forward path gain discrepancies.
E. For unity gain and are level compensated by automatic gain and slope control systems utilizing RF pilot
reference carriers
Answer: CE 
5. HFC cable television return path networks are aligned to provide: (multiple answer)
A. Asymmetrical gain since the downstream and upstream bandwidths are also asymmetrical
B. Unity gain with a fixed input level and varying output levels adjusted by the selection of a fixed value
attenuator and equalizer at the output stage in each of the return amplifiers in the network
C. Unity gain with a fixed output level and varying input levels adjusted by the selection of a fixed value
attenuator and equalizer at the input stage of each of the return amplifiers in the network
D. Cable modems the ability to power range comfortably within their output power dynamic range
E. It is not necessary to align the return path amplifiers since the CMTS will automatically adjust the cable
modem transmit power levels.
Answer: BD 
6. Cisco recommends the use of a headend-grade coaxial cable or a quad-shield coaxial cable with a minimum of
60% + 40% braid and double foil insulation to connect the cable modem cards to the HFC network. The center
conductor must be straight and extend 1/8 inch (3.2 mm) beyond the end of the connector, and the connector
should be securely crimped to the cable. Select three recommended cable types that can be used to connect the
Cisco uBR7200 series universal broadband routers: (multiple answer)
A. RG 58
B. RG 59
C. RG 59/U
D. RG 6
E. RG 7
Answer: BCD 
7. Given a PAL HFC and 8 MHz channel lineup in the downstream, is it possible to utilize 6 MHz DOCSIS cable
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modems and signals on the network?
A. No, only 8 MHz channel spacing is available for Downstream data signals
B. Yes, as long as the 6 MHz DOCSIS signal is within a valid 8 MHz channel
C. Yes, as long as the DOCSIS signal is upconverted through a PAL upconverter
D. No, DOCSIS cannot be mixed with EuroDOCSIS in the Donwstream
E. DOCSIS must be used only in an EIA-542 channel plans
Answer: B 
8. In a cable HFC plant, which devices are modulators? (multiple answer)
A. CMTS line card
B. Upconverter
C. Diplex filter
D. Set top box
E. Fiber node
Answer: AD 
9. Unity gain is being used for alignment. The first amplifier from the node has 25 dB of gain and is 2000 feet
away with cable loss of 1 dB per 100 feet. The node has an output of 35 dBmV at 55.25 MHz. What is the input at
the amplifier?
A. 13dBmV
B. 3dBmV
C. 15dBmV
D. 27dBmV
Answer: C 
10. There are two different headends with two different frequencies available sharing the same plant. There is a
-10dB cable loss to the second active in the cascade. What is the required pad for balancing
A. A 0 pad
B. A 1 pad
C. A 2 pad
D. A 3 pad
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E. A 4 pad
F. A 5 pad
Answer: F 
11. A DOCSIS 2-way data system is being designedto limit upstream traffic. Unknown modems should be kept
from using precious Upstream bandwidth. Given these requirements, it should beensured that the DOCSIS
configuration file has what set?
A. Vendor-specific information field
B. Max-cpe should be set to 1
C. CMTS authentication field should be set
D. Network Access should be set to 0
E. Downstream frequency should be set above 450 MHz
Answer: D 
12. The name of the DOCSIS config file to download will be offered to the cable modem in what DHCP field?
A. giaddr
B. config-filename
C. packet-filename
D. siaddr
Answer: C 
13. Every time a typing mistake is made at the exec prompt of a router, the message from the router indicates a
lookup is being performed. Also, there is a waiting period of several seconds before the next command can be
typed. Can this behavior be changed?
A. No, this is a built in feature of Cisco IOS? software.
B. Yes, use the no ip domain-lookup command.
C. Yes, use the no ip helper-address command.
D. Yes, use the no ip multicast helper-map command.
E. Yes, use the no exec lookup command.
Answer: B 
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14. Upon deleting an IOS image file from flash, an execution of show flash shows the file still in flash, with a 'D'
preceding it (as shown in the exhibit). What step must be taken in order to remove the file completely? 
A. Erase the file from flash
B. Format the flash device
C. Replace the flash card - it is defective
D. Execute a squeeze command on the flash device
Answer: D 
15. What effect will this configuration command have?
line vty 0 4
no password vtypassword 
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A. All telnet connections to the router will be denied.
B. Only one telnet connection at the router will be allowed at a time.
C. Virtual terminal sessions will not be able to enter enable mode.
D. Virtual terminal sessions will not be asked a user-level password.
E. It will have no effect.
Answer: A 
16. For an OC-48 signal (2.5Gb/s), what is the BER (bit error rate) if there is 1 bit error every four days?
A. 10E-12
B. 10E-13
C. 10E-14
D. 10E-15
E. 10E-16
Answer: D 
17. For communications systems what describes the over-all health of the system?
A. Bit-Error-Rate (BER)
B. Synchronous Optical NETwork (SONET)
C. Optical Signal to Noise Ratio (OSNR)
D. None of the above
Answer: A 
18. What is NOT an ATM class of service?
A. CBR
B. VBR-t
C. ABR
D. UBR
E. CAR
Answer: E 
19. What describes a technique, used to encapsulate voice (NOT data) over ATM?
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A. RFC 1483
B. LANE
C. AAL-1
D. RFC 1577
Answer: C 
20. What is the purpose of rate decoupling for ATM transmission?
A. It provides transparency between SONET and SDH.
B. It converts higher-speed DS3/E3 to lower-speed optical rates.
C. It processess the packing and unpacking of frames into 53-octet cells.
D. It allows lower-speed traffic on an ATM facility without causing traffic gaps.
Answer: D 
21. The ATM reference model is composed of which ATM layers? (multiple answer)
A. ATM layer
B. Physical layer
C. Modular layer
D. ATM adaptation layer
Answer: ABD 
22. What mechanism should be employed to limit the "transmit rate" from Router A to Router C? 
A. Committed Access Rate
B. Traffic Shaping
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C. Weighted Fair Queuing
D. Packet Classifcation w/ Weighted Fair Queuing
E. None of the Above
Answer: B 
23. Router A has a 512K-access port into the frame relay cloud. Router B has 128K-access port into the frame
relay cloud. The two routers are connected with symmetrical PVCs that are configured for 64K committed
information rate (CIR). What Frame Relay Traffic Shaping map-class sub-command should be entered on Router
A to prevent workstation A from overrunning the access port on Router B? 
A. frame-relay traffic-rate 128000 512000
B. frame-relay traffic-rate 64000 512000
C. frame-relay traffic-rate 512000 64000
D. frame-relay traffic-rate 128000 64000
E. frame-relay traffic-rate 64000 128000
Answer: E 
24. The CLI command "show cable hop":(multiple answer)
A. Indicates corrected and uncorrected errors in the upstream.
B. Indicates power level and upstream SNR.
C. Identifies the upstream receiver port that is supporting the modems causing customer service calls.
D. Indicates that cable modem is at maximum power level.
E. Identifies manufacturer of the cable modem, and associated MAC address.
Answer: AC 
25. In this diagram, Host G is attempting to send a packet to Host A through Router E. All routers are running
EIGRP, and Router E has installed the following route in its routing table:1.1.0/24 via router FWhat will occur
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when Router E receives packets from Host G that are destined for Host A? 
A. E cannot have a route to 10.1.1.0/24 through F; so it will always choose the path through C.
B. This is a routing loop; E will forward the traffic to F, and F will send the traffic back to E.
C. Router E will forward the traffic to Router F.
D. Router E will forward the traffic to Router F and send a 'host not reachable this direction' ICMP packet to Host
G.
E. Router E will forward the traffic to Router F and send an ICMP redirect to Host G.
Answer: E 
26. Routers E and F are running HSRP (Hot Standby Router Protocol). Router E has a higher priority, and both
routers have standby preempt configured. Since Router E is normally the active router, what IP address should
Host G use for its default gateway? 
A. 10.1.3.1
B. Router E's IP address, since it is normally active; Router F will take over Router E's address if it fails.
C. Router F's IP address; the active router will take over the standby router's IP address until it fails
D. The virtual address configured when enabling HSRP
E. The virtual address assigned by HSRP; this address is dependent on the group number configured
Answer: D 
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27. Which can occur if cables other than those recommended for connecting the uBR7200 series cable modem
line card(s) to the HFC network are used? (multiple answer)
A. The modulation error ratio (MER) will increase.
B. The carrier-to-noise ratio (CNR) will increase.
C. The line card F connectors may be damaged.
D. Co-channel interference may occur in long, parallel cable runs.
E. Common mode currents will occur on the outer surface of the cable shield.
Answer: CD 
28. When using IS-IS for IP routing, Dual IS-IS defined by RFC 1195, what is true? (multiple answer)
A. It is necessary to configure a NSAP address.
B. It is not possible to perform both IP and CLNS routing wih the same process.
C. IP address and subnet information is carried in the TLV field on the L-1/L-1 LSPs.
D. Dual IS-IS does not support VLSM information.
Answer: AC 
29. To eliminate the need for adjacent routers on broadcast networks to form n(n-1)/2 adjacencies, IS-IS defines a
pseudonode or Designated Intermediate System, DIS. All router on the broadcast medium form an adjacency with
the DIS. The Backup DIS is called:
A. Redundant DIS
B. BDR
C. There is no concept of a backup DIS in IS-IS
D. Designated Redundant System
Answer: C 
30. The configuration shown is for a RateMux in a Motorola headend feeding an IRT while remapping inputs
from SA MDR feeds. What statement is true concerning this configuration?
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A. The packet gap must be 0.
B. The PSIRate must be 700.
C. The CA Sys_ID must be 47 49.
D. The NULL value must be 400k.
Answer: C 
31. Program PID=0 is always:
A. PAT
B. PMT
C. CAT
D. NIT
E. EMM
Answer: D 
32. In a reorganization, OSPF areas are realigned. Is this a valid network design? If not, which changes could be
made to the network and/or router configurations? (multiple answer)
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A. No changes are necessary.
B. A virtual link could be configured between Area 60 and Area 0.
C. A serial line or other physical connection could be installed between devices in Area 60 and Area 0.
D. Router B could be configured as an Area Border Router between Area 60 and Area 6.
E. This is not a valid design, and no changes can make it work.
Answer: BC 
33. Based on the information above, which OSPF configurations listed are valid? (multiple answer) 
A. routerArouter ospf 1network 14.0.0.0 0.255.255.255 area 0routerBrouter ospf 1network 14.0.0.0 0.255.255.255
area 0
B. routerArouter ospf 1network 14.1.1.0 0.0.0.255 area 0routerBrouter ospf 2network 14.1.1.0 0.0.0.255 area 0
C. routerArouter ospf 1network 14.0.0.0 0.0.255.255 area 0routerBrouter ospf 1network 14.1.0.0 0.0.0.255 area 0
D. routerArouter ospf 1network 14.1.1.0 0.0.0.255 area 1routerBrouter ospf 1network 14.1.0.0 0.0.255.255 area 0
Answer: AB 
34. How should OSPF be configured on Router B?
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A. router ospfnetwork 108.3.0.0
B. router ospf 1network 108.3.100.0 0.0.0.255 area 6network 108.3.2.0 0.0.0.255 area 6
C. router ospf 1network 108.3.100.0 0.0.0.255 area 6network 108.3.2.0 0.0.0.255 area 0
D. router ospf 1network 108.3.100.0 255.255.255.0 area 6network 108.3.2.0 255.255.255.0 area 6
E. router ospf 1network 108.3.1.0 0.0.0.255 area 6network 108.3.100.0 0.0.0.255 area 6network 108.3.2.0
0.0.0.255 area 6
Answer: B 
35. A router is set up to redistribute routing updates from OSPF to RIP. What answer best describes issues the
network administrator needs to be aware of?
A. Split Horizon, Poison Reverse, Holddown
B. Slow convergence, limited hop-count metric, lack of network mask information, periodic broadcasts
C. None, OSPF is a link-state routing protocol which overcomes issues found in RIP.
D. Difference in metrics (e.g. hops vs. cost), subnet mask allocation/addressing (e.g. VLSM vs. fixed subnet mask
length), routing protocol summarization (e.g. network boundaries)
Answer: D 
36. A router has the above routes listed in its routing table and receives a packet destined for 172.16.0.45. What
will happen?
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A. The router will not forward this packet, since it is destined for the 0 subnet.
B. The router will forward the packet through 172.31.116.65, since it has the lowest metric.
C. The router will forward the packet through 10.1.1.1.
D. The router will forward the packet through 172.31.116.65, since it has the lowest administrative distance.
E. The router will forward the packet through 192.168.1.4.
Answer: C 
37. Which addresses below are appropriate supernets to contain the addresses shown in the exhibit? (multiple
answer) 
A. 192.168.0.0/16
B. 192.168.0.0/19
C. 192.168.32.0/19
D. 192.168.1.0/24
Answer: AB 
38. According to the diagram, what attribute is initiated by AS200 (IBGP) to give preference to the path A or D
traffic will take when going from AS200 to AS100? What attribute is initiated by AS200 (EBGP) to give
preference to the path B or C traffic will take when going from AS100 to AS200?
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A. MED; Origin
B. MED; Local Preference
C. Community; Origin
D. Local Preference; MED
E. Origin; Community
Answer: D 
39. Customers green and blue must communicate with each other. Which condition is required? 
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A. Customer Blue and Customer Green must use BGP for routing to the Internet.
B. Customer Blue and Customer Green must use unique addresses in their corporate networks.
C. All Service Provider routers must use BGP.
D. The Service Provider must provide BGP Peering to another Service Provider.
Answer: B 
40. BGP can implement a policy of 'Route Dampening' to control route instability. What statement about route
dampening is NOT correct?
A. A numeric penalty is applied to a route each time it flaps.
B. The penalty is exponentially decayed according to parameters, such as half-life-time.
C. The history of unstable routes is forwarded back to the sender to control future updates.
D. The route is eventually suppressed based on a configurable 'suppress limit'.
Answer: C 
41. In BGP, why should a Route Reflector be used?
A. To overcome issues of split-horizon within BGP
B. To reduce the number of External BGP peers by allowing updates to reflect without the need to be fully meshed
C. To allow the router to reflect updates from one Internal BGP speaker to another without the need to be fully
meshed
D. To divide Autonomous Systems into mini-Autonomous Systems, allowing the reduction in the number of peers
E. None of the above
Answer: C 
42. If a host sends a TCP segment with the RST flag set, it means:
A. The receiver should send all data in the reassembly buffer to the application receiving it immediately.
B. The receiver should reset the session.
C. Any routers between the source and destination hosts should reset the state of the connection in their buffers.
D. The receiver should make certain its send buffer is pushed onto the wire.
Answer: B 
43. The "show controllers cable x/y upstreram x" command does not detect impulse noise because:
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A. It does measure impulse noise but it is an estimate.
B. Ingress is measured in microseconds and can't be detected.
C. Ingress is measured in milliseconds and can't be detected.
D. Impulse is measured in microseconds and can't be detected.
E. Impulse noise is detected but based on an average.
Answer: D 
44. In the "show cable flap-list" what issues can causes a flap to be incremented? (multiple answer)
A. "hit" followed by a "miss"
B. Modem keeps trying to quickly reregister
C. Cable modem goes offline
D. After six consecutive misses
E. "miss" followed by a "hit"
Answer: BDE 
45. What would be the best method for determining the cause of CPEs not getting provisioned an address?
A. Turn on "debug ip dhcp" in the uBR for all DHCP requests
B. At the failing modem issue the command "debug cable mac log"
C. Check the uBR's system log for errors
D. Make sure the MAC address is populated within client-class-processing
E. Monitor the DHCP log file in CNR
Answer: E 
46. What command on the Ubr7246 can help find the possibility of a problem with ingress noise on cable x/y
upstream? (multiple answer)
A. Show controller cable x/y upstream z
B. Debug cable mac log verbose
C. Debug cable modulation
D. Show cable hop
E. Show int cable x/y upstream z
Answer: ADE
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47. How can decreasing the interleave-depth value effect performance?
A. It increase the time to transmit a packet.
B. It decreases the upstream transmission rate.
C. It reduces the time needed to transmit a packet.
D. It increases the downstream transmission rate.
E. It increases the time between transmission of a MAP packet
Answer: C 
48. In the exhibit, the cable modem 00e0.6f00.6ef6 is "flapping" likely due to: 
A. The cable modem RF power adjustments caused by intermittent return path gain
B. Excessive "Hits" and cable modem RF power adjustments caused by intermittent return path gain
C. Poor forward path signal level or carrier to noise ratio.
D. Excessive "Hits" and cable RF power adjustments due to intermittent downstream gain
E. None of the above
Answer: A 
49. How can you buffer upstream grants instead of dropping packets causing TCP retransmissions
A. Traffic shaping
B. Set the max transmit upstream burst to 0
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C. Traffic policing
D. Modulation profiles
E. Set the max transmit upstream burst to 255
Answer: A 
50. What IOS command, entered on cisco cable modem with console access, is most valuable for determining the
cause of a modem not being able to come on-line?
A. show controller c 3/0 modem 0
B. show interface c 3/0
C. debug ip dhcp detail
D. debug cable mac log verbose
E. show cable modem
Answer: D 
51. Incrementing hits with a corresponding excessive number of incrementing misses displayed in a flap list for a
given modem can be an indication of: (multiple answer)
A. Noisy return path performance
B. A modem that has been turned off or disconnected from the system
C. A modem that failed to respond to consecutive "keep alive" polls
D. A modem that has needed to reestablish its link more than once within the configured flap-list insertion-time
Answer: AC 
52. The return path interference designated by the four "diamond shape" markers on the spectrum analyzer display
depicted in the exhibit is most likely caused by:
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A. Return path distributed feedback laser clipping
B. Forward path signals mixing in an undesired "diode like" connection and/or corrosion at some point in the
downstream coaxial network
C. A faulty cable modem transmitter somewhere on the affected return path
D. Downstream laser clipping or laser non-linearities
E. None of the above
Answer: B 
53. What ISDN timer is started after Q.931 SETUP msg is sent?
A. T301
B. T303
C. T302
D. T310
E. T305
Answer: B