Cisco 642-845 Exam - CheatYourExams.net

Free 642-845 Sample Questions:

1. Which one of the following statements correctly describes an FXO interface?
A. analog trunks that connect a gateway to plain old telephone service (POTS) device such as analog phones, fax machines, and legacy voice­mail systems
B. analog trunks that provide the Survivable Remote Site Telephony (SRST) feature
C. analog trunks that provide VoIP gateway functionality
D. analog trunks that connect a gateway to a central office (CO) or private branch exchange (PBX)
Answer: D

2. Cisco AutoQoS is innovative technology that minimizes the complexity, time, and operating cost of Quality of Service (QoS) deployment. Which two steps are executed in the deployment of Cisco AutoQoS for Enterprise? (Choose two.)
A. The customer uses SNMP statistics to create the policy.
B. QoS policy templates are generated and installed on the interface.
C. The auto­generated policy is manually optimized before implementation.
D. Auto­discovery is used to determine what traffic is on the interface.
Answer: B,D

3. Quality of Service (QoS) refers to the capability of a network to provide better service to selected network traffic over various technologies .Which two options are true about the application of QoS in a converged network? (Choose two.)
A. End­to­end network delay is not a factor as long as the delay is consistent.
B. Some packet loss can be corrected by codec algorithms.
C. End­to­end network delay times that exceed 50 ms for real­time traffic are considered unacceptable.
D. End­to­end network delay times that exceed 250 ms for real­time traffic are considered unacceptable.
Answer: B, D

4. Network topology exhibit:
You are a network technician at XXYYinc.com, examine the exhibit carefully. You need to finalize the configuration of router TIS­R in this scenario. In particular you should decide which interface types can be used for connecting router TIS­R to the phone and fax respectively. (Choose two.)

A. Connect the analog phone to an FXS port.
B. Connect the fax to an FXS port.
C. Connect the fax to an FXO port.
D. Connect the analog phone to an FXO port.
Answer: A, B

5. Look at the following options, which one is not a benefit of VoIP compared to traditional circuit­switched telephony?
A. Access to new communication devices
B. Consolidated network expenses
C. Improved employee productivity
D. Higher voice quality
Answer: D

6. On the basis of the following traffic descriptions, which one is used for marking?
A. FIFO Layer 2 descriptor labels (L2DL)
B. WRED (Weighted RED) orange or green labels
C. MPLS experimental bits
D. Header compression tags
Answer: B

7. You are a network technician at XXYYinc.com, do you know what are two of the three predefined classes for the Cisco SDM wizard? (Choose two.)
A. best effort
B. middle class
C. high priority
D. business­critical
Answer: A, D

8. You work as a network technician, study the following options carefully.A GRE tunnel is configured between a local and a remote site. Where should the service policy be applied to classify packets based on the pretunnel header?
A. Apply the service policy on the physical interface but do not use the qos pre­classify command.
B. In global configuration mode, apply the service policy and use the qos pre­classify command.
C. In global configuration mode, apply the service policy but do not use the qos pre­classify command.
D. Apply the service policy on the tunnel interface but do not use the qos pre­classify command.
Answer: D

9. Which option is not considered one of the main methods to tackle the bandwidth availability problem?
A. Use compression techniques.
B. Increase (upgrade) the link bandwidth.
C. Forward large packets first.
D. Classify and mark traffic and deploy proper queuing mechanisms.
Answer: C

10. Refer to the capabilities of a voice gateway router ,which statement is true?
A. Voice gateways need a gatekeeper to interconnect the VoIP networks with the PSTN network.
B. Voice gateways equipped with a DSP module can take the role of the call agent during WAN failure.
C. Voice gateways with Cisco Unified CallManager Express (CME) can permanently act as a call agent for IP phones.
D. Voice gateways with analog interfaces need a gatekeeper to convert analog signals into digital format before voice is encapsulated into IP packets.
Answer: C

11. You work as a network engineer at XXYYinc.com, study the exhibit carefully. What type of interface will connect the voice gateway router TIS1 to the XXYYinc phone and the fax machine?

A. The XXYYinc phone will be connected to the FXS port, and the fax machine will be connected to the FXO port on router TIS1.
B. Both devices will be connected to the E and M ports on router TIS1.
C. Both devices will be connected to the FXS ports on router TIS1.
D. The XXYYinc phone will be connected to the FXO port, and the fax machine will be connected to the FXS port on router TIS1.
Answer: C

12. You work as a network engineer at XXYYinc.com, so you should know the sampling rules. One of the most important rules of sampling is called the Nyquist Theorem, which states that the highest frequency which can be correctly represented is less than one­half of the sampling rate. On the basis of the Nyquist theorem, what sampling rate is required to support voice frequencies of up to 4000 Hz?
A. 4000 samples per second
B. 2000 samples per second
C. 6000 samples per second
D. 8000 samples per second
Answer: D

13. Cisco AutoQoS is innovative technology that minimizes the complexity, time, and operating cost of Quality of Service (QoS) deployment. Which option is correct about the configuration of AutoQoS on a Frame Relay interface?
A. Multilink PPP (MLP) over Frame Relay must be manually configured on low speed DLCIs.
B. AutoQoS can be configured on a Frame Relay DLCI only if a map class is attached to the DLCI.
C. For low­speed Frame Relay DLCIs with Frame Relay­to­ATM Interworking, the AutoQoS cannot be configured if a virtual template is already configured for the DLCI.
D. AutoQoS can be configured from a different subinterface if the DLCI is already assigned to one subinterface.
Answer: C

14. Wired Equivalent Privacy (WEP) is a deprecated algorithm to secure IEEE 802.11 wireless networks. Which one of the following statements is not a weakness of WEP?
A. Because with basic WEP the wireless client does not authenticate the access point, the client can be victimized by rogue access points.
B. With enough data captured, even with initialization vector used, the WEP key can be deducted.
C. WEP is vulnerable to dictionary attacks.
D. The WEP usage of certificates is not convenient for some customers.
Answer: D

15. If you are a network technician, can you tell me what are two major sources of delay that can be managed by QoS in voice­enabled networks? (Choose two.)
A. packets dropped because of CRC errors
B. propagation delay
C. header overhead
D. congested egress queues
Answer: C, D

16. Which one of the following descriptions is correct about the Cisco 2700 Location Appliance collection of location information for wireless devices?
A. The APs collect received signal strength indication (RSSI) information from all Wi­Fi devices and forward the information to the Cisco Wireless Location Appliance through the LWAPP.
B. An AP collects RSSI information which is forwarded to wireless controllers through LWAPP. Wireless controllers forward aggregated RSSI to the location appliance through SNMP.
C. The Cisco WLAN controllers bypass the received signal strength indication (RSSI) information from all Wi­Fi devices to the Cisco Wireless Location Appliance through LWAPP.
D. All Wi­Fi devices on the WLAN send directly received signal strength indication (RSSI) information to the Cisco Wireless Location Appliance through SNMP.
Answer: B

17. You are a network technician at XXYYinc.com.Your task is to extend QoS in the XXYYinc network to include wireless LAN. In which device or devices is wireless QoS implemented for Cisco Lightweight AP split­MAC architecture?
A. The Wireless LAN Controller only
B. The AP only
C. Between the AP and Catalyst switch via 802.1p
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D. Between the AP and Wireless LAN Controller via LWAPP
Answer: D

18. Which two options about the DiffServ QoS model are correct? (Choose two.)
A. The flow­based approach of the DiffServ model is ideal for large scalable implementations such as the public Internet.
B. The DiffServ model is more scalable than the IntServ model.
C. DiffServ requires RSVP to set up a path through the network to accommodate the requested QoS.
D. Network traffic is identified by class, and the level of service is chosen for each class.
Answer: B, D

19. WLSE­Express provides complete enterprise­class security and control in an integrated solution package. What are two features of WLSE­Express wireless management? (Choose two.)
A. centralized management with integrated AAA server
B. integration with the Location Appliance to expand real time tracking to 2500 devices for 30 days
C. integration with the Location Appliance to expand real time tracking to 1500 devices for 30 days
D. centralized management for autonomous access points
Answer: A, D

20. Which one is not considered a valid classification traffic descriptor?
A. Source or destination address
B. Traffic path
C. IP precedence or DSCP value
D. Incoming interface
Answer: B

21. Which three descriptions are correct about the application of QoS models? (Choose three.)
A. The DiffServ model requires applications to signal the network with QoS requirements.
B. The best effort model is suitable for applications such as file transfer and e­mail
C. The IntServ model requires applications to signal the network with QoS requirements.
D. The DiffServ model can be used to deliver QoS based upon IP precedence, or source and destination addresses.
Answer: B, C, D

22. Study the exhibit carefully. The serial link connecting the two offices has a bandwidth of 128 kbps. What could be done to set aside 64 kbps of bandwidth to transport VoIP traffic over the WAN link?

A. Apply the auto­cost reference­bandwidth 64 command on both sides of the serial link.
B. Apply the ip bandwidth­percent eigrp 1 64 command on both sides of the serial link.
C. Apply the frame­relay voice­bandwidth 64000 command to enable the QoS Call Admission Control feature on the serial link.
D. Apply the max­conn 64 command on a perial peer basis on both sides of the serial link.
Answer: C