CCNA 4 - Modul 3

1. Which best describes the benefit of using Frame Relay as opposed to a leased line or ISDN service?

** Customers only pay for the local loop and the bandwidth they purchase from the network provider.

2. Which statement about Frame Relay subinterfaces is correct?

** Point-to-point subinterfaces act like leased lines and eliminate split-horizon routing issues.

3. What best describes the use of a data-link connection identifier (DLCI)?

** locally significant address used to identify a virtual circuit

4. What is created between two DTEs in a Frame Relay network?

** virtual circuit

5. Which two items allow the router to map data link layer addresses to network layer addresses in a Frame Relay network? (Choose two.)

** Inverse ARP
** LMI status messages

6. Refer to the exhibit. What can be known about the configuration of router R1 from the output?

** The command encapsulation frame-relay ietf has been used on the Serial 0/0/0 interface.

7. Refer to the exhibit. Which two outcomes occur from the configuration shown? (Choose two.)

** The router will use DLCI 22 to forward data to 10.1.1.1.
** Frames arriving on interface serial 0/0/0 of RT_1 will have a data link layer address of 22.

8. Refer to the exhibit. What effect does the point-to-point configuration on subinterface S0/0.110 have on the operation of the router?

** It eliminates split horizon issues without increasing the likelihood of routing loops.

9. Refer to the exhibit. You are a network administrator who has been tasked with completing the Frame Relay topology that interconnects two remote sites. Router HQ belongs to both the 172.16.1.0/24 and 172.16.2.0/24 subnets with IP addresses of 172.16.1.3 and 172.16.2.3 respectively. Traffic between R1 and R2 must travel through HQ first. How should the serial interface on HQ be configured to complete the topology?

** two point-to-point subinterfaces

10. Refer to the exhibit. What can be determined about the configuration of router R1 from the exhibited output?

** The LMI type for the Serial 0/0/0 interface has been left to its default configuration.

11. Refer to the exhibit. What can be determined about the Frame Relay switch from the output shown?

** It is experiencing congestion.

12. Refer to the exhibit. Which two statements are true given the output shown? (Choose two.)

** The local DLCI number is 401.
** Inverse ARP is being used on this connection.

13. Refer to the exhibit. A ping is sent to address 192.168.50.10 from the Peanut router. Which DLCI will be used to send the ping?

** 110

14. Refer to the exhibit. Router R1 has been configured for Frame Relay connectivity to routers R2 and R3. Which set of configuration options for routers R2 and R3 would provide each router connectivity to R1?

** R2(config)# interface serial0/0/1.201 point-to-point
R2(config-if)# frame-relay interface-dlci 201
R3(config)# interface serial0/0/1.301 point-to-point
R3(config-if)# frame-relay interface-dlci 301

15. Refer to the exhibit. Which statement explains why the Frame Relay connection between R1 and R2 is failing?

** The frame-relay map commands are using incorrect DLCIs.

16. Refer to the exhibit. Router R2 is part of a Frame Relay network that uses OSPF for IP routing. After the commands that are shown are entered, R2 will not exchange OSPF information correctly. What is the likely cause?

** The frame-relay map command requires the broadcast keyword.

17. Refer to the exhibit. When troubleshooting a Frame Relay connection, an administrator entered the show interfaces s0/0 command and received the output shown in the exhibit. What are two probable reasons for this problem? (Choose two.)

** The router is not configured for the same Frame Relay PVC as the switch.
** The LMI type on the Frame Relay switch is NOT ANSI.

18. Refer to the exhibit. What can be determined from the output?

** Serial 0/0/0 has been configured with an DLCI of 201.

19. What consideration must be taken into account if RIP is used on Frame Relay multiaccess networks?

** To forward routing updates, address-to-DLCI mapping must be done via the use of the frame-relay map command coupled with the broadcast keyword.

20. Which three actions does a Frame Relay switch perform when it detects an excessive build-up of frames in its queue? (Choose three.)

** drops frames from the queue that have the DE bit set
** sets the FECN bit on all frames it receives on the congested link
** sets the BECN bit on all frames it places on the congested link

21. What two methods does Frame Relay technology use to process frames that contain errors? (Choose two.)

** Frame Relay services depend on the upper layer protocols to handle error recovery.
** The receiving device drops any frames that contain errors without notifying the sender.

22. Refer to the exhibit. Router R1 has been configured for Frame Relay connectivity to routers R2 and R3. What configuration option should be configured on the R2 and R3 serial interfaces in order for all routers to ping each other successfully?

** R2(config-if)# frame-relay map ip 10.1.1.1 201 broadcast
R2(config-if)# frame-relay map ip 10.1.1.3 201 broadcast
R3(config-if)# frame-relay map ip 10.1.1.1 301 broadcast
R3(config-if)# frame-relay map ip 10.1.1.2 301 broadcast

CCNA 4 - Modul 2

1. 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.

2. 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.

3. Refer to the exhibit. What statement is true regarding the output shown?

** The PAP passwords did not match, so the routers are trying CHAP authentication.

4. Why are serial connections preferred over parallel connections for long transmission lengths?

** Parallel connections are subject to clock skew and to crosstalk between wires.

5. Which two statements are true about time-division multiplexing (TDM)? (Choose two.)

** Multiple sources can transmit over a single channel.
** Original data streams must be reconstructed at the destination.

6. Which authentication protocol can be spoofed to allow playback attacks?

** PAP

7. What function do Network Control Protocols provide for a PPP connection?

** to allow multiple Layer 3 protocols to operate over the same physical link

8. 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

9. What advantage does PPP have over HDLC for serial communications?

** It supports authentication

10. Which PPP configuration option can be used to establish load balancing over the interfaces of a router?

** multilink

11. 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.

12. 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.

13. Refer to the exhibit. What statement is true regarding the output shown?

** Data is able to flow across this link.

14.
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)

15. 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

16. 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.

17. 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.

18. Refer to the exhibit. Which statement is true about PPP operation?

** Both the link-establishment and network-layer phase completed successfully.

19. 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.

20. Which two options can LCP negotiate? (Choose two.)

** link quality
** authentication

21. Refer to the exhibit. On the basis of the show interface Serial0/0 output, how many NCP sessions have been established?

** two

CCNA 4 - Modul 1

1. Which statement about WAN protocols is correct?

** Most WAN protocols use HDLC or a variant of HDLC as a framing mechanism.

2. Which statement is true of the functionality of the layers in the hierarchical network model?

The distribution layer aggregates WAN connections at the edge of the campus.

3. Which WAN technology uses a fixed payload of 48 bytes and is transported across both switched and permanent virtual circuits?

** ATM

4. A U.S. company requires a WAN connection used only to transfer sales data from individual stores to the home office. All transfers will occur after business hours. The required bandwidth for this connection is estimated to be less than 38 kbps. Which type of connection requires the least investment for this company?

** analog dialup

5. What is an advantage of packet-switched technology over circuit-switched technology?

** Packet-switched networks can efficiently use multiple routes inside a service provider network.

6. Which statement is true about data connectivity between a customer and a service provider?

** The segment between the demarcation point and the central office is known as the "last mile."

7. What are two advantages of an analog PSTN WAN connection? (Choose two.)

** low cost
** availability

8. What can cause a reduction in available bandwidth on a cable broadband connection?

** number of subscribers

9. For digital lines, which device is used to establish the communications link between the customer equipment and the local loop?

** CSU/DSU

10. At which two layers of the OSI model does a WAN operate? (Choose two.)

** Physical Layer
** Data Link Layer

11. A company needs a WAN connection that is capable of transferring voice, video, and data at a minimum data rate of 155 Mbps. Which WAN connection is the best choice?

** ATM

12. Which statement is true about the differences between a WAN and a LAN?

** A WAN often relies on the services of carriers, such as telephone or cable companies, but a LAN does not.

13. Which networking device is typically used to concentrate the dial-in and dial-out traffic of multiple users to and from a network?

** access server

14. Why is the call setup time of a circuit-switched WAN implementation considered a drawback?

** Data cannot be transferred until a circuit has been established.

15. What three terms are associated with ISDN PRI? (Choose three.)

** circuit switching
** data bearer channels
** time-division multiplexing

16. Which three features are identified with Frame Relay connections? (Choose three.)
** CIR
** DLCI
** PVC

17. Which two devices are commonly used as data communications equipment? (Choose two.)

** modem
** CSU/DSU

18. Which packet-switched WAN technology offers high-bandwidth connectivity capable of managing data, voice, and video all on the same infrastructure?

** metro Ethernet

19. Which three WAN devices can be found in the cloud? (Choose three.)

** ATM switches
** core routers
** Frame Relay switches

20. Which switching type will allow the communication devices in the provider network to be shared and only allocated to an individual subscriber during data transfer?

** dedicated switched lines

21. What type of connectivity is established when VPNs are used from the remote site to the private network?

** tunnels

22. Which term describes a device that will put data on the local loop?

** DCE