Tuesday, February 5, 2008

Final Exam

1 An ISDN circuit from a branch office is remaining connected to the regional office. A network administrator determines a user has initiated a continuous ping from a desktop computer to the regional office. Which configuration change would allow the ISDN circuit to disconnect during any attempts to ping, while otherwise functioning properly?
• change DDR from legacy to dialer profiles
• remove the dialer list statement from the configuration
* change the dialer list to exclude ICMP as interesting
• disable inverse ARP

2

Refer to the exhibit. The link between the RTR-1 and RTR-2 routers is configured as shown in the exhibit. Although the show interfaces command shows the interface status as Serial0 is up, line protocol is up, IP traffic is not crossing this link. What is the problem?
• The usernames are misconfigured.
• The clock rate is configured on the wrong end of the link.
* The IP addresses are not in the same subnet.
• Interface serial 0/0 on RTR-1 must connect to interface serial 0/1 on RTR-2.
• The passwords must be different for the CHAP authentication.
• The clock rate must be 56000.

3 A technician enters the interface serial 0/0.1 multipoint command when configuring a router. What effect will the multipoint keyword have in this configuration? (Choose two.)
* Split-horizon issues will need to be resolved for this network if RIP is the routing protocol.
• A subinterface will be defined for each PVC.
* All the participating interfaces of remote routers will be configured in the same subnet.
• A single DLCI will be used to define all the PVCs to the remote routers.
• An IP address will need to be configured on the main interface.

4 A branch office reports excessive connect time charges for an ISDN circuit used to connect to the regional office. Upon investigation of this issue, it is discovered that when an ISDN connection is initiated to the regional office it remains connected for an excessive amount of time. Which of the following configuration changes could be made to DDR on the router to reduce these connect time charges?
• use PPP multilink
* lower idle timer setting
• use CHAP authentication
• change DDR from legacy to dialer profiles

5

Which router command would be used to associate a Layer 2 address with the corresponding Layer 3 address in the internetwork in the diagram?
• RouterA(config-if)#frame-relay pvc 100 192.168.15.2
• RouterA(config-if)#dialer-map ip 192.168.15.1 100 broadcast
* RouterA(config-if)#frame-relay map ip 192.168.15.2 100 broadcast
• RouterA (config-if)#dialer-map 192.168.15.1 101 serial 0 broadcast
• RouterA (config-if)#frame-relay dlci 101 192.168.15.1 broadcast
• RouterA (config-if)#dialer-map 192.168.15.1 inverse-arp broadcast

6 What does the output of the show frame-relay map command shown below represent? (Choose two.)
Serial 0 (up): ip 172.30.151.4 dlci 122, dynamic, broadcast, status defined, active
* 172.30.151.4 represents the IP address of the remote router.
• 172.30.151.4 represents the IP address of the local serial interface.
• DLCI 122 represents the interface of the remote router.
* broadcast indicates that a dynamic routing protocol such as RIP v1 can send packets across this PVC.
• dynamic indicates that a dynamic routing protocol is enabled for this connection.
• active indicates that the ARP process is working.

7

Refer to the exhibit. The network administrator of the Denver router has determined that the DHCP clients on the network are not working properly. The clients are receiving IP configuration information from a DHCP server configured on the router but cannot access the Internet. From the output in the exhibit, what is the most likely problem?
• The DHCP server service is not enabled.
• The DHCP pool is not bound to the interface.
• The inside interface for DCHP is not defined.
* The pool does not have a default router defined for the clients.
• All the host addresses have been excluded from the DHCP pool.

8 What are two ways to resolve split-horizon issues in a Frame Relay network? (Choose two.)
* create a full-mesh topology
• disable Inverse ARP
* use point-to-point subinterfaces
• use multipoint subinterfaces
• remove the broadcast keyword from the frame-relay map command

9

What is the purpose of the command marked with an arrow shown in the partial configuration output of a Cisco 806 broadband router?
• defines which addresses are allowed out of the router
• defines which addresses are allowed into the router
* defines which addresses can be translated
• defines which addresses are assigned to a NAT pool

10 Which scenarios present possible reasons for using the frame-relay map command when configuring a Frame Relay connection? (Choose two.)
* when dynamic mapping of DLCIs to IP addresses is not supported by the remote router
• when the local router is using IOS Release 11.1 or earlier
• when the remote router is a non-Cisco router
• when globally significant rather than locally significant DLCIs are being used
* when broadcast traffic and multicast traffic over the PVC must be controlled

11 While testing a new network design in the lab, a network administrator is configuring a serial link that connects two routers back-to-back. In order to finish the configuration, the administrator needs to identify which router is connected to the DCE end of the cable. What command can be issued to provide this information?
• router# show status serial 0/0
* router# show controllers serial 0/0
• router# show protocols serial 0/0
• router# show version
• router# show interfaces serial 0/0

12 Which statements are correct about the point in the network where the responsibility of the service provider ends? (Choose three.)
* The International point is on the customer side of the network terminating unit(NTU).
* The United States point is at the interface of the customer-provided equipment and the local loop.
• The responsibility for this point is controlled by IANA.
* The point is called the demarcation point.
• The point is typically located at the service provider's central office.
• The point is located between the customer's local area networks.

13

A system administrator is unable to ping the Serial0/0 interface of RouterB from RouterA. During the troubleshooting process, the following facts are established:
- IP addressing and subnet masks are correct.
- RouterA is a Cisco router and RouterB is a router from another vendor.
- RouterA is configured with the default encapsulation.
- The serial interfaces on both routers are up.
- The protocol is down on the serial interfaces of both routers.

What should the administrator do to solve the problem?

• Add a clock rate on RouterA.
• Enable the serial interface on RouterB.
* Change the encapsulation on both routers to PPP.
• Connect the serial cable to the correct interface on RouterB.
• Use the correct serial cable to attach the CSU/DSU to RouterB.

14 When a Frame Relay switch detects an excessive buildup of frames in its queue, which of the following may occur? (Choose two.)
* Frames with the DE bit set are dropped from the switch queue.
• Frames with the FECN and BECN bits set are dropped from the switch queue.
• Frames in excess of the CIR are not accepted by the switch.
• The switch sets the FECN bit on all frames it places on the congested link and sets the BECN bit on all frames it receives on the congested link.
* The switch sets the FECN bit on all frames it receives on the congested link and sets the BECN bit on all frames it places on the congested link.

15

Refer to the exhibit. A network administrator is checking the status of router RTR_2. What is the most likely reason for the current status of the serial link to RTR_1?
* A cable has become disconnected.
• The circuit is experiencing excessive RFI.
• Authentication is not properly configured on the routers.
• The routers are configured for different WAN encapsulations.
• The clock rate is not properly configured on one of the routers.

16 What are two of the steps required to configure a router to connect over ISDN BRI? (Choose two.)
• Configure the interface with a DLCI.
* Configure the SPIDs, if required by the ISDN switch.
• Specify the the LMI type to be compatible with the CO switch.
• Set the interface encapsulation to the Cisco or IETF frame type.
• Configure a subinterface for each B channel.
* Set the switch type to work with the ISDN switch at the CO.

17 What value in the address field of a Frame Relay header identifies the destination of the frame?
• CIR
• DE
* DLCI
• ISDN
• FRAD
• PVC

18 Which of the following describes the roles of devices in a WAN? (Choose three.)
* A CSU/DSU terminates a digital local loop.
• A modem terminates a digital local loop.
• A CSU/DSU terminates an analog local loop.
* A modem terminates an analog local loop.
* A router is commonly considered a DTE device.
• A router is commonly considered a DCE device.

19

Refer to the exhibit. Two routers are connected through a Frame Relay point-to-point PVC. The ILM-5 router is from a vendor other than Cisco. Which interface command is required to configure the link between the Cisco ILM-3 router and router ILM-5?
• ILM-3(config-if)# encapsulation frame-relay cisco
• ILM-3(config-if)# frame-relay pvc multipoint
* ILM-3(config-if)# encapsulation frame-relay ietf
• ILM-3(config-if)# frame-relay lmi-type ansi
• ILM-3(config-if)# frame-relay pvc point-to-point

20 The output of the show interfaces serial 0/0 command for a frame-relay connection indicates that the serial line is up but the line protocol is down. What are possible causes for this? (Choose two.)
* There is an LMI-type mismatch between the Frame Relay switch and the router.
* There is no clock present on the serial interface.
• The interface is shut down.
• RARP is not functioning on the router.
• The cable is disconnected.

21 After configuring a dialup ISDN circuit, a network associate begins testing the dialup connection. When attempting to ping a host on the remote network, the local router does not attempt to dial the remote access server. Which of the following are possible errors in this configuration? (Choose three.)
• PPP authentication is not properly configured.
* No dialer map is configured.
• The ISDN circuit connected to the remote access server is busy.
* No interesting traffic is defined.
* No route is determined to the remote network.
• A wrong number is configured in the dial string.

22 When configuring a Frame Relay network with subinterfaces, which commands are configured on the subinterface? (Choose three.)
* frame-relay interface-dlci
• encapsulation frame-relay ietf
* ip address
* frame-relay map
• switch type

23 Below is a list of DDR steps. Which of the following identifies the proper order of DDR?

1 - dial number is looked up
2 - interesting traffic triggers DDR
3 - route to destination is determined
4 - call is made

• 1,2,3,4
• 1,3,2,4
• 2,3,1,4
• 2,1,3,4
* 3,2,1,4
• 3,1,2,4

24 A network administrator issued the command show frame-relay pvc. The response from the router shows the status of a PVC as deleted. What is the reason for this output?
• The DLCI is using the wrong LMI type.
• The DLCI is usable but has little activity.
• The DLCI is programmed in the switch but the circuit is not usable.
* The DLCI was formerly programmed in the switch but is no longer there.

25

The serial PPP link between the Left and Right routers is configured as shown in the diagram. Which configuration issue explains why the link is unable to establish a PPP session
• The IP addresses must be on different subnets.
* The usernames are misconfigured.
• The passwords must be different for the CHAP authentication.
• The clock rate must be 56000.
• The clock rate is configured on the wrong end of the link.
• Interface serial 0/0 on Left must connect to interface serial 0/1 on Right.

26 Which protocol should be chosen to support WAN connectivity in a multi-vendor system and provide strong security through authentication?
• NAT with DHCP
• Frame Relay
• HDLC with encryption
• HDLC with CHAP
• PPP with PAP
* PPP with CHAP

27

Refer to the exhibit. Which statements describe why the workstation with the IP address 192.168.89.99 cannot access the Internet? (Choose two.)
• The NAT outside interface is not configured properly.
* The NAT inside interface is not configured properly.
• The access control list does not include the IP address 192.168.1.99/28 to access the Internet.
• The NAT pool is not properly configured to use routable outside addresses.
* The NAT pool is not properly configured to use the access control list for NAT.

28 After the ISDN BRI interface is configured, which command can be used to verify that the router is communicating correctly with the ISDN switch?
• show dialer
* show isdn status
• show interfaces bri0/0:1
• show interfaces serial0/0.1

29 How are the settings for ISDN switch type and SPIDs determined for a BRI interface configuration?
• assigned by the network administrator
• randomly, so long as they are not duplicated on the network
• by trial and error
• dynamically via Inverse ARP
• assigned by IANA
* assigned by the service provider

30 A network administrator is having difficulty in establishing a serial link between a Cisco router and a router from another vendor. Both routers are configured for HDLC encapsulation. Which statements are true regarding this configuration? (Choose two.)
* The Cisco HDLC frame uses a proprietary "Type" field that may not be compatible with equipment of other vendors.
• HDLC requires a clock rate to be configured on the routers at both ends of the serial link.
* PPP encapsulation is recommended for serial links between equipment from multiple vendors.
• Usernames must be configured at both ends of the HDLC serial link.
• The HDLC vendor type must be enabled on the Cisco router.
• There is a mismatch in the HDLC authentication password configurations.

31

A system administrator is troubleshooting a connectivity issue between two routers in a new installation. The administrator enters the debug ppp authentication command on the WHSE router. The graphic shows a part of the output received. From this output, what is the most likely cause of this connectivity issue?
• There is not a route to the remote router.
• The ISDN circuit on the remote router has failed.
* The username/password was not properly configured on the WHSE router.
• The remote router has a different authentication protocol configured.

32 A system administrator needs to configure the regional office with ISDN for DDR connections to three remote sites. Each remote site requires different IP subnets, different encapsulations, and different authentication methods. The sites will not be connected at the same time. The company would like to accomplish this in the most cost effective manner. What method can the system administrator use to accomplish this task using the fewest B channels?
• Install and configure a PRI.
• Install and configure a BRI interface with separate SPIDs for each remote site.
• Install and configure a BRI with multiple switch types in global configuration.
* Install and configure a BRI using dialer profiles.
• Install and configure a separate BRI for each remote site.

33 Which IP addresses are defined by RFC 1918 as private addresses? (Choose three.)
• 172.55.16.0.16
* 172.17.0.0/16
• 224.200.175.0/24
* 192.168.168.0/22
• 10.88.179.0/29
• 17.250.0.0/16

34 Which of the following statements are correct regarding PAT? (Choose two.)
• PAT is the best method to provide consistent global addresses for network servers.
• PAT can only be configured to use one IP address, which is usually the IP address of the serial interface of the router.
• PAT uses unique source port numbers on the inside local IP address to distinguish between translations.
* PAT uses unique source port numbers on the inside global IP address to distinguish between translations.
* When PAT is configured to use a pool of IP addresses and exhausts the ports of the first IP address, the router will move to the next available IP address.

35 Which circuit-switched WAN technology is often used to provide a backup for a leased line and additional capacity during peak usage times?
• X.25
• DSL
* ISDN
• cable modem

36 Which of the following is the order for the three phases of establishing a PPP serial link with authentication?
• authentication, link-establishment, network layer protocols
• authentication, network layer protocols, link-establishment
• network layer protocols, link-establishment, authentication
• network layer protocols, authentication, link-establishment
* link-establishment, authentication, network layer protocols
• link-establishment, network layer protocols, authentication

37 What causes a DDR call to be placed?
• dial string
• DLCI
• idle time out
* interesting traffic
• PVC

38 A system administrator must provide Internet connectivity for 25 hosts at an insurance agency. The ISP has assigned two public IP addresses to this company. What can the administrator do to provide Internet access to all 25 users at the same time?
* Configure the router with dynamic NAT with PAT.
• Configure the router with dynamic NAT for 25 users.
• Configure the router with DHCP and static NAT.
• Configure the router with static NAT for all 25 users.
• This cannot be done with only two public addresses.

39

A network administrator must provide WAN connectivity between the Central office and three remote sites: East Branch, West Branch, and Remote. The East Branch and West Branch offices receive sales orders and transmit shipping confirmations to the Central office consistently throughout the day. The Remote office is staffed by one salesperson who travels through the northwestern territory. The salesperson occasionally needs to connect to the Central office for e-mail access. How should the network administrator connect these sites to the Central office? (Choose two.)
• Connect the East Branch and West Branch remote offices with ISDN connections.
* Connect the East Branch and West Branch offices with Frame Relay connections.
• Connect the East Branch and West Branch offices with POTS dial-up connections.
• Connect the Remote office with a Frame Relay connection.
• Connect the Remote office with an ISDN connection.
* Connect the Remote office with a POTS dial-up connection.

40 Which of the following ISDN protocols is responsible for call setup and call teardown?
• ITU-T Q.921
* ITU-T Q.931
• ITU-T I.430
• ITU-T I.431

CCNA 4 - module 6 exam answers

1 For which platform was UNIX first marketed commercially?
• workstations and servers
• workstations
* network servers
• large mainframe systems

2 How does RMON gather statistics on a segment?
• analyzes traps on the segment
• polls packets on the segment
* analyzes every frame on the segment
• analyzes source and destination addresses

3 Which operating systems support multiuser capability? (Choose three.)
* Linux
• Windows 98
• Windows ME
* Windows XP
* Windows 2000

4 Which statements are true regarding configuring SNMP? (Choose three.)
• It is best to use the default read-only community strings in enterprise networks.
* It is not advisable to use the default read-write community string in an enterprise network.
* More than one read-only community string is supported.
* Authorized management stations can modify MIB objects with read-write access specified.
• The maximum number of read-write strings supported is one.

5 Which statements describe the Windows 2000 operating system family? (Choose three.)
* .NET Server was designed to run enterprise level web and FTP services.
• Active Directory services run on both Windows 2000 Professional and Windows 2000 Server.
* The entire family of Windows 2000 operating systems can operate as a file, print, FTP or web server.
• Both Windows 2000 Professional and Server can support up to 256 simultaneous dialup sessions.
* .NET server was designed to compete with Linux and Unix.

6 Which of the following is a collection of software which includes a GUI interface to allow the network administrator to monitor and manage the network?
* network management application
• network management agent
• management information base
• network management protocol

7 Which command would enable logging on all supported destinations?
• Router(config)# logging 131.152.0.0
• Router(config)# logging routerA
* Router(config)# logging on
• Router(config)# logging enable

8 How does SNMPv3 address the security shortcomings of SNMPv1 and SNMPv2c?
• improved SMI features
• support for centralized and distributed management
* secure access to MIBs
• control of heterogeneous networks

9 Which means of communication does an SNMP network agent use to provide a network management station with important but unsolicited information?
• query
• broadcast
• ICMP ping
* trap
• poll

10 Which of the following describes the community strings used for SNMPv1 and SNMPv2c? (Choose two.)
* The community strings are sent using UDP.
• The read only string on most devices is set to private.
• The read/write string on most devices is set to public.
• Only the NMA needs to be configured with the community strings.
* The community strings are sent across the network in cleartext.

11

In the above illustration, which configuration commands can be used to specify the location of a managed device and the main system contacts for the device? (Choose two.)
• SanJose(config-if)# snmp-server SanJose
* Atlanta(config)# snmp-server contact JPSmith
• Atlanta(config)# snmp contact JPSmith
* SanJose(config)# snmp-server location SanJose
• Chicago#(config)# snmp chicago

12 Which features are supported by the Mac OS X system that make it a competitive choice for operating systems? (Choose four.)
* protected memory
• sixty-two bit addressing
* preemptive multitasking
• open source operating system code
* symmetric multiprocessing
* Appletalk-to-Windows network connectivity

13 An SNMPv1 agent would issue a GetResponse message to reply to which NMS requests? (Choose three.)
* GetRequest
• GetBulkRequest
* GetNextRequest
* SetRequest
• GetNextbulkRequest

14 Why are SNMPv1 and SNMPv2c community strings considered a security risk?
• SNMPv1 and SNMPv2c encapsulations are not encrypted by default.
* SNMPv1 and SNMPv2c community strings are sent as cleartext.
• SNMPv1 and SNMPv2c are limited to 32-bit counters.
• SNMPv1 and SNMPv2c uses a connectionless protocol.

15 Which of the following does SNMP use to hold information collected about the network?
• network management station
• network management database
* management information base
• database information agent

16 Which of the following are examples of network management applications? (Choose two.)
• Windows 2000 Professional
* Ciscoworks2000
* HP Openview
• Red Hat Linux
• Cisco ConfigMaker

CCNA 4 - module 5 exam answers

1 How does Frame Relay technology process frames that contain errors? (Choose two.)
* Frame Relay services depend on the upper layer protocols to handle error recovery.
• It requires the receiving device to request that the sender retransmit erroneous frames.
• FECN, BECN, and DE bits are set in the frames to minimize errors.
* The receiving device drops any frames that contain errors without notifying the sender.
• The frame relay switch notifies the sender that errors were detected.

2 Which statement identifies a reason for using point-to-point subinterfaces in Frame Relay networks?
* Subinterfaces overcome routing update and split-horizon issues that occur with multipoint logical interfaces on a single physical interface.
• A point-to-point subinterface does not require an IP address and therefore saves address space.
• Point-to-point subinterfaces provide greater reliability and reachability in Frame Relay networks by requiring a mesh topology for network configurations.
• Point-to-point subinterfaces increase the number of DLCIs that can be configured in a Frame Relay network.

3

A ping is sent to address 192.168.50.10 from the Peanut router. Which DLCI will be used to send the ping?
* 110
• 115
• 220
• 225

4 Which data link layer protocol is used to carry frames across a Frame Relay link?
• PPP
• LAPD
* LAPF
• Frame Relay

5 Which bits are set in the data frames to request that a device reduce the flow of data sent to or from a Frame Relay switch?
• EIR bits
* ECN bits
• CIR bits
• DE bits
• Window bits

6 Why are full mesh topologies seldom found in large Frame Relay networks?
• Additional hardware is required to achieve the mesh.
• The additional virtual circuits slow the link access speeds.
* The required number of links becomes prohibitive.
• Additional interfaces are required since each can only support 10 virtual circuits.
• The speed of transmission slows in inverse proportion to the square of the number of links.

7 Which of the following occurs when the command frame-relay map ip 10.1.1.1 22 is configured on the router? (Choose two.)
• DLCI 22 will replace the MAC address in the ARP table for entry 10.1.1.1
• The remote circuit with DLCI 22 can receive a ping.
• Inverse-ARP will be used to add an entry for 10.1.1.1 into the frame-relay map table using DLCI 22.
* Pings to 10.1.1.1 will be sent on the circuit labeled DLCI 22.
* The router will use DLCI 22 to forward data to 10.1.1.1.

8 Why is the keepalive mechanism added as an extension to the Local Management Interface in a Frame Relay network?
• to identify which routers were experiencing congestion
* to verify the status of PVCs in the Frame Relay network
• to dynamically map a MAC address to an IP address in a Frame Relay network
• to signal to the router the status of the routing protocols configured in the Frame Relay network

9 Which of the following statements are true about a basic Frame Relay WAN connection between a customer and the service provider? (Choose two.)
* DTE devices such as routers and FRADs transmit user data.
• DTE devices such as Frame Relay switches transport the data between DTE devices.
• An Ethernet connection between the router and the frame relay switch allow access to the frame relay network.
* Serial connections between the customer and the frame relay network are used to transport data.
• The Frame Relay WAN is a mesh of interconnected routers.

10 What is created between two DTEs in a Frame Relay network?
* switched parallel circuit
* permanent virtual circuit
• limited access circuit
• ISDN circuit
• Frame Relay circuit

11 Which features make Frame Relay technology a cost-effective alternative to a mesh of dedicated leased lines? (Choose three.)
* allows a single interface to support multiple PVCs
* minimizes the equipment required to be purchased by the customer
• requires one router interface for each PVC
• provides the customer with redundancy if a single interface goes down
* allows the customer to pay for the average bandwidth requirement rather than the maximum bandwidth requirement

12 Which of the following allow the router to map data link layer addresses to network layer addresses in a Frame Relay network? (Choose two.)
• ARP
• RARP
• Proxy ARP
* Inverse ARP
* LMI status messages
• ICMP

13

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 cable between the CSU/DSU and the router is disconnected.
• The serial 0/0 interface is shutdown.
* 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.
• The address of the Frame Relay switch is not in the routing table.

14

Which commands were added to the configuration to produce the output shown in the graphic? (Choose two.)
• Router(config)# ip route 192.168.192.4 255.255.255.0 17 broadcast
• Router(config-if)# frame-relay lmi-type cisco 17
* Router(config-if)# frame-relay map ip 192.168.192.4 17 broadcast
• Router(config-if)# ip address 192.168.192.4 255.255.255.0 DLCI 17 static
• Router(config-if)# interface S0/0.1 point-to-point
* Router(config-if)# encapsulation frame-relay cisco

15 What does a DLCI of 1023 indicate about a frame?
• The LMI type is ANSI.
• The LMI type is IETF.
* The LMI type is Cisco.
• The LMI type is Q933a.
• The encapsulation is Cisco.
• The encapsulation is IETF.

16 Which methods are used to minimize heavy traffic on a Frame Relay network? (Choose two.)
• FRADs or routers set ECN bits to request that the Frame Relay switch reduce the flow of frames on the link.
• Windowing is used to reduce the size of the frames sent across the link.
* The Frame Relay switch will drop packets that have the DE bit set.
* When a switch sees its queue increasing, it notifies DTEs to reduce the flow of traffic.
• When congestion occurs, all frames are dropped until the congestion clears.

17

When troubleshooting a frame relay connection, a technician entered the show frame-relay pvc command shown in the graphic. What can be concluded from the output shown in the graphic? (Choose three.)
* The output in the debug frame-relay lmi command will indicate status 0x2 for DLCI 18.
* DLCI 16 was correctly programmed on the switch, but the remote router may be misconfigured.
* The frame relay switch is sending LMI status messages about DLCI 16 to the Singapore router.
• Congestion has been experienced on DLCI 18.
• Some packets have been set to be dropped if congestion is experienced on the PVC.

18 Which of the following DLCIs are reserved?
• 16
• 127
• 255
* 1023
• 2048

19 Which of the following statements regarding multipoint subinterfaces are true? (Choose two.)
* A single multipoint subinterface is used to establish PVC connections to multiple physical interfaces on remote routers.
• Each multipoint link is in its own subnet.
* The physical interface does not have an IP address.
• Split-horizon is disabled allowing routing updates to be re-transmitted on every subinterface.
• Multipoint subinterfaces require the encapsulation frame-relay command to be issued individually for each subinterface to operate correctly.

20 How is a permanent virtual circuit identified in a Frame Relay network that is carrying IP traffic?
* It is given a fixed locally significant identification number.
• It is identified by the MAC address of the router interface.
• Dynamic virtual channel identifiers are assigned to each frame transmitted across the network.
• It is identifed by the MAC address of the switch port.

21 What is the purpose of the FCS field in a Frame Relay frame?
• It serves to distinguish one frame from the next.
• It is used to signal network congestion.
* It is used to detect if the frame has been corrupted and should be discarded.
• It determines which VC should be used for transmission.

CCNA 4 - module 4 exam answers

1 Which of the following correctly describes ISDN BRI? (Choose three.)
* two 64 kbps B channels and one 16 kbps D channel
* B channel is suitable for voice data
• uses in-band signaling
* uses out-of-band signaling
• offers the equivalent of a T1/E1 connection
• twenty-three 64 kbps B channels and one 16 kbps D channel

2 Which of the following is considered out-of-band signaling?
• using a frequency outside of the rated bandwidth for transmission
• transmitting data over a control channel
* using a separate channel for control signals
• transmitting control signals over a data channel

3 A network administrator is troubleshooting ISDN connectivity. The administrator suspects the problem lies with the authentication protocol. What command should the administrator use to view the authentication process between the router and the ISDN switch?
• debug pap authentication
• debug chap authentication
* debug ppp authentication
• debug isdn authentication

4 Which router command would be used to enter the mode for configuring a T1 PRI connection?
* Router(config)# controller t1 {slot/port}
• Router(config)# interface pri t1 {slot/port}
• Router(config)# interface pri {slot/port} t1
• Router(config)# controller {slot/port} t1

5

The network administrator of XYZ company needs to configure a new ISDN router. After entering the commands shown in the graphic, the administrator tries to access the Internet but the ISDN connection does not open. If the service provider verifies that the problem is with XYZ's configuration, what is a possible cause of the problem?
• The dialer map is configured incorrectly.
• The encapsulation type is configured incorrectly.
* The dialer group is configured incorrectly.
• The ACL is configured incorrectly.
• The isdn switch-type command needs to be configured globally.

6 Which of the following protocols can be used to encapsulate data traffic sent from a router BRI interface? (Choose two.)
• Link Access Protocol - Data
* High-Level Data Link Control
• Logical Link Control
• Serial Data Link Control
* Point to Point protocol
• Binary Synchronous Control protocol

7

A small company uses an ISDN WAN link to transfer e-mail to remote sites. What command would the administrator use to determine if the ISDN link is up?
* show isdn status
• show isdn active
• show dialer
• show interface bri0/0
• debug isdn active

8 Which command configures an ISDN interface to use a switch type which is different from that used on other interfaces on the router?
• Router(config)#switch-type switch-type
• Router(config-if)#switch-type switch-type
• Router(config)#isdn switch-type switch-type
* Router(config-if)#isdn switch-type switch-type

9 Which of the following is essential for all ISDN BRI interface configurations?
* ISDN switch type
• line encoding technique
• line framing method
• local directory number
• service profile identifier

10 You have just taken delivery of a new US standard Cisco 2620 router that includes a BRI "U" interface? Which of the following describes how this router will be connected in the ISDN network?
• An external terminal adapter (TA) must be attached to the router for connectivity.
• An NT1 must be connected to the router for connectivity.
* The router is a TE1 device and is ready to connect to the provider's network.
• The router is a TE2 device and requires both a TA and NT1 for connectivity.

11 What must be configured for an ISDN PRI connection? (Choose three.)
* ISDN switch type
• Service Profile Identifier (SPID)
• Dial-on-Demand Routing (DDR)
* PRI group time slot
* T1/E1 controller, framing type and line coding

12

A network administrator is troubleshooting an ISDN connectivity problem. Users are complaining they cannot connect to the Internet. The network administrator suspects the ISDN connection attempt is timing out before a connection can be established. What command would the network administrator use to determine what the "wait for carrier" timeout value is set to?
• show isdn status
• show isdn active
* show dialer
• show interfaces bri0/0
• debug isdn q931
• show ISDN interfaces

13 What is a reason why static routes are preferred over dynamic routes for DDR to operate on an ISDN interface?
• An ISDN interface will not allow dynamic routing updates that use broadcast technology.
• A dynamic route will take precedence over a static route because of its lower administrative distance.
• Dynamic routing can never be considered interesting traffic by default.
• Dialer-list configuration does not support dynamic routing.
* Dynamic routes may cause the ISDN connection to dial constantly to transmit updates.

14 Which of the following describes the use of a SPID? (Choose two.)
• selects the ISDN switch type
* identifies the line configuration of the BRI service
* allows multiple ISDN devices to share the local loop
• designates whether a device is a TE1 or TE2
• allows ISDN broadcasts

15 Which command is used within an existing ISDN network to display current call information, including the called number?
• show isdn status
* show isdn active
• show interfaces bri0/0
• show ip interfaces

16 Which of the following are true of ISDN routers configured with dialer profiles? (Choose two.)
• They do not use ACL to define interesting traffic.
* Their B channels can be configured with different subnets and encapsulation types.
* Their BRI interfaces can belong to multiple dialer pools.
• They use PPP only.
• They can only use the CHAP authentication protocol.

17 A network administrator in Europe has been asked to provide the network with an ISDN WAN link. The router available to provide the WAN connection is a non-modular Cisco router with an S/T interface. What further equipment will be provided by the ISDN service provider for the ISDN connection?
• Nothing. The router is already suitable.
• BRI WAN interface card to install in the router
* an external NT1 to terminate the local loop
• a TA/NT1 device to install on the router

18 Why must routers be configured to specify the ISDN switch type?
* Switches use various implementations of Q.931.
• The IOS of most routers lacks the ability to autosense the switch.
• The switch must know what type of router it is communicating with.
• The Layer 3 connection between the terminal equipment and the ISDN switch is not standardized.

CCNA 4 - module 3 exam answers

1 A technician is testing the functionality of a recently installed router. The technician is unable to ping the serial interface of a remote router. The technician executes the show interface serial 0/0 command on the local router and receives the following output:
Serial0/0 is up, line protocol is down(disabled)
What are possible causes for this command output? (Choose two.)
• interface missing the no shutdown command
• clockrate command missing
* CSU/DSU failed
* interface shutdown due to high error rate
• cable missing

2 A technician has used Telnet to gain remote access to a router that has no connectivity on its serial interface. Which command should be issued to determine if the serial cable is connected properly?
* show controllers
• show processes
• show run
• show status

3 A two router network is running PPP over the serial interfaces that connect them. The enable password on the Denim router is "gateway". The Denim router also has a locally configured authentication password for the Plaid router which is "fortress". Which command must be executed on the Plaid router to allow Denim to authenticate to the Plaid router using CHAP?
• Plaid(config)# enable secret gateway
• Plaid(config)# enable secret fortress
• Plaid(config)# username Plaid password fortress
* Plaid(config)# username Denim password fortress
• Plaid(config)# hostname Plaid secret password gateway
• Plaid(config)# hostname Plaid secret password fortress

4

Refer to the output of the show interface Serial0/0 command in the graphic. How many NCPs have been established?
• 1
* 2
• 3
• 4

5 Which command specifies a link quality over a PPP link?
• ppp link 50
• ppp link quality 60
• ppp percentage 80
* ppp quality 90

6 When troubleshooting the Serial 0/0 interface of a router, a technician issues the show controllers command. The following was the output of the command:

Interface is Serial0/0, electrical interface is UNKNOWN.

What can be concluded about the Serial 0/0 interface? (Choose three.)

* Serial0z0 is down, line protocol is down
• Serial0/0 is down, line protocol is up
• Serial0/0 is up, line protocol is down
• The interface is neither DCE or DTE.
* The interface hardware may be faulty.
* The cabling may be improperly connected.

7 Which of the following is a reason for using such protocols as PAP and CHAP?
• to establish a PPP session
• to provide error checking on a WAN link
* to restrict access to networks connected by serial and ISDN links
• to provide a backup hostname and privilege mode password on the router

8 Several tasks must occur before a link between two routers can pass data using PPP. Which of the following are required to establish and maintain a PPP session between two routers?
• configure each host with a PPP address
• configure authentication between the two routers
* send LCP and NCP frames to negotiate configuration parameters
• send hostname and password information between the two routers

9 Which of the following describes the High-Level Data Link Control protocol? (Choose three.)
* HDLC provides flow and error control.
• Standard HDLC supports multiple protocols on a single link.
* HDLC uses sequencing and acknowledgements.
• HDLC is defined as the default encapsulation on Cisco LAN interfaces.
* Cisco implemented a proprietary version of HDLC.

10 Which authentication protocol can be spoofed to allow playback attacks?
• MD5
• CHAP
* PAP
• NCP

11 ISDN BRI service uses two B channels to send data, voice, and video. If the first channel becomes saturated, the second channel can be configured to forward packets. Which command will allow ISDN to load balance across both links?
• Router(config-if)# ppp quality 2
• Router(config-if)# ip variance
• Router(config-if)# ip maximum-paths 2
* Router(config-if)# ppp multilink

12 PPP uses several protocols for communication. Which of the following are options that the LCP protocol in the PPP architecture can provide? (Choose two.)
* testing the quality of the link
• routing packets between devices
• assigning individual station addresses
• configuring network layer protocols
• negotiating authentication options

13 How did Cisco alter the HDLC encapsulation to allow a single link to carry multiple protocols?
• split the transmissions into multiple channels each carrying a single protocol
• identified the protocol in the FCS field
• compressed the datagrams differently for each protocol
* added a type field to identify the protocol

14 Which of the following is an advantage of using time-division multiplexing (TDM) for transmitting data? (Choose two.)
• It allows a single source to transmit over multiple data channels.
* Multiple sources can transmit over a single channel.
* Original data streams must be reconstructed at the destination.
• TDM relies on Layer 3 protocols to operate.

15

What can be concluded from the output shown in the graphic? (Choose three.)
• A two-way handshake is occuring.
* The LCPs were already negotiated.
* The router can begin NCP negotiations.
• The debug ppp negotiation command was executed.
* The debug ppp authentication command was executed.

16

Which command was used to display the partial output shown in the graphic?
• show ppp traffic
• show lcp traffic
* debug ppp negotiation
• debug ppp authentication

17 How is the MD5 function valuable in authentication? (Choose two.)
* uses a one-way hash function
• authentication occurs more rapidly
* challenges are unique
• the remote router assumes control of frequency of challenge
the remote router assumes control of timing of challenge

18 What are three features of the CHAP protocol? (Choose three.)
* exchanges a random challenge number during the session to verify identity
• sends authentication password to verify identity
* prevents transmission of login information in plain text
* disconnects the PPP session if authentication fails
• initiates a two-way handshake

19 Which of the following describe functions of the Point-to-Point protocol with regards to the OSI model? (Choose three.)
• PPP uses Layer 3 of the OSI model to establish and maintain a session between devices.
• PPP operates at all layers of the OSI model.
* PPP uses the data link layer to configure such options as error detection and compression.
* PPP provides a mechanism to multiplex several network layer protocols.
• PPP uses Network Control Protocols (NCP) to test and maintain connectivity between devices.
* PPP can be configured on both synchronous and asynchronous serial interfaces.

20 Which advantage does the multilink option provide when using PPP?
* Data transmission has load balancing possibilities.
• Interfaces can be configured using both HDLC and PPP.
• More than one authentication method can be used.
• More than one compression protocol can be configured.

CCNA 4 - Module 2 Exam Answers

1 Which of the following is commonly used as Data Terminal Equipment?
• ISDN
• modem
* router
• CSU/DSU

2 Which term describes the cabling that connects the customer site to the nearest exchange of the WAN service provider?
• CPE
• CO
* local loop
• DCE
• DTE

3 On which of the following are most Layer 2 WAN encapsulations based?
• IP
• PPP
* HDLC
• SLIP
• HSSI
• CSU

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?
• ATM
• ISDN
* analog dialup
• T1 Leased Line

5 A company requires a WAN connection that will carry 64 kbps and allow fast call setup time. The connection does not need to carry video. What is the best choice for this company?
• ATM
* ISDN BRI
• X.25
• analog dialup

6 Which of the following describes a packet-switched network using connection-oriented data transfer? (Choose two.)
* Each packet carries an identifier.
• Each packet carries full addressing information.
• Each switch in the route must evaluate the addressing information to determine where to send the packet.
• Each switch determines where to send the packet by examining tables in memory.
• The addressing information is used to set switches along the route of data transfer to create a continuous copper circuit.

7 Which of the following connections will provide the equivalent of a T1/E1 connection and is intended for large businesses?
• BRI
* PRI
• DLCI
• PSTN
• POTS

8 A large company already has a T1 leased line but this connection is inadequate at peak business hours. Furthermore, they would like a backup WAN connection in case their leased line temporarily fails. What type of WAN connection is commonly used in this situation?
• X.25
• DSL
* ISDN
• cable modem
• 56 kbps

9 Which of the statements regarding DSL are correct? (Choose three.)
• DSL provides a consistent bandwidth of 2.154 Mbps.
• DSL connections provide a fast dialup to establish a WAN connection.
* DSL connects the local loop to a digital subscriber line access multiplexer.
* DSL bandwidth varies and can exceed the bandwidth of a T1/E1 leased line.
* For DSL to function properly, the local loop must be less than 5.5 kilometers (3.5 miles).
• DSL is a popular choice for enterprises that need to connect home users to the local network due to strong security.

10 A European company needs a low cost, dialup WAN connection to validate transactions for point-of-sale card readers. Which connection type is commonly used for this situation?
• ATM
* X.25
• Frame Relay
• Leased lines

11 Which statement is true regarding WAN technologies?
• Most WANS use only one technology throughout the infrastructure such as ISDN, Frame Relay or ATM.
• Data transfer speeds on the WAN are typically faster than the speeds on a LAN.
* WANs operate at the lower three layers of the OSI model.
• WANs are unable to support the transfer of voice or video traffic.

12 Depending on the company size and geographical layout, there might be many end points on the company WAN. Why is it important to identify all the end points of the WAN before choosing a WAN design?
• to determine the routing protocol to be used on the WAN link
* to determine the WAN topology
• to determine the requirements for latency and jitter
• to determine the signaling protocol to be used on the WAN link

13 Which of the following is true of WANs?
• Shared network WAN technologies such as Frame Relay and ATM are more expensive but offer less latency and jitter than dedicated lines.
• ISDN is suitable for large enterprises.
* The more network devices that data has to pass through across the WAN, the more latency and less reliability the network will experience.
• WANs typically incorporate only one technology such as ISDN, Frame Relay, or ATM.

14 Which statements are correct regarding ATM connections? (Choose two.)
• uses only PVCs
* is useful for video transfers
* has data rates beyond 155 Mbps
• cells have 32 byte payload and a 5 byte overhead
• mandates single virtual circuits on a single leased line connection

15 Why is it important to identify the type of traffic that will be carried on the WAN links before choosing a WAN technology?
• to determine the routing protocol to be used on the WAN link
• to determine the WAN topology
* to determine the requirements for latency and jitter
• to determine the type of signaling protocol to be used on the WAN link

16 A new international company needs to have a design for WAN connectivity. The company will have at least five offices in every state in the United States and Mexico. Some states will have as many as 20 offices. The branch offices will require constant contact with the services of the main office. Which design model is best for WAN connectivity in this situation?
• a mesh network of all branch WANs
• a simple star topology connecting all branch LANs to a central router with multiple interfaces
• a one layer design using Frame Relay links between LANs
* a three layer hierarchical topology interconnecting branch LANs within an area, the area LANs within a region, and connecting the regions to form the core of the WAN

CCNA 4 - Module 2 Exam Answers

1 A technician is testing the functionality of a recently installed router. The technician is unable to ping the serial interface of a remote router. The technician executes the show interface serial 0/0 command on the local router and receives the following output:
Serial0/0 is up, line protocol is down(disabled)
What are possible causes for this command output? (Choose two.)
• interface missing the no shutdown command
• clockrate command missing
* CSU/DSU failed
* interface shutdown due to high error rate
• cable missing

2 A technician has used Telnet to gain remote access to a router that has no connectivity on its serial interface. Which command should be issued to determine if the serial cable is connected properly?
* show controllers
• show processes
• show run
• show status

3 A two router network is running PPP over the serial interfaces that connect them. The enable password on the Denim router is "gateway". The Denim router also has a locally configured authentication password for the Plaid router which is "fortress". Which command must be executed on the Plaid router to allow Denim to authenticate to the Plaid router using CHAP?
• Plaid(config)# enable secret gateway
• Plaid(config)# enable secret fortress
• Plaid(config)# username Plaid password fortress
* Plaid(config)# username Denim password fortress
• Plaid(config)# hostname Plaid secret password gateway
• Plaid(config)# hostname Plaid secret password fortress

4

Refer to the output of the show interface Serial0/0 command in the graphic. How many NCPs have been established?
• 1
* 2
• 3
• 4

5 Which command specifies a link quality over a PPP link?
• ppp link 50
• ppp link quality 60
• ppp percentage 80
* ppp quality 90

6 When troubleshooting the Serial 0/0 interface of a router, a technician issues the show controllers command. The following was the output of the command:

Interface is Serial0/0, electrical interface is UNKNOWN.

What can be concluded about the Serial 0/0 interface? (Choose three.)

* Serial0z0 is down, line protocol is down
• Serial0/0 is down, line protocol is up
• Serial0/0 is up, line protocol is down
• The interface is neither DCE or DTE.
* The interface hardware may be faulty.
* The cabling may be improperly connected.

7 Which of the following is a reason for using such protocols as PAP and CHAP?
• to establish a PPP session
• to provide error checking on a WAN link
* to restrict access to networks connected by serial and ISDN links
• to provide a backup hostname and privilege mode password on the router

8 Several tasks must occur before a link between two routers can pass data using PPP. Which of the following are required to establish and maintain a PPP session between two routers?
• configure each host with a PPP address
• configure authentication between the two routers
* send LCP and NCP frames to negotiate configuration parameters
• send hostname and password information between the two routers

9 Which of the following describes the High-Level Data Link Control protocol? (Choose three.)
* HDLC provides flow and error control.
• Standard HDLC supports multiple protocols on a single link.
* HDLC uses sequencing and acknowledgements.
• HDLC is defined as the default encapsulation on Cisco LAN interfaces.
* Cisco implemented a proprietary version of HDLC.

10 Which authentication protocol can be spoofed to allow playback attacks?
• MD5
• CHAP
* PAP
• NCP

11 ISDN BRI service uses two B channels to send data, voice, and video. If the first channel becomes saturated, the second channel can be configured to forward packets. Which command will allow ISDN to load balance across both links?
• Router(config-if)# ppp quality 2
• Router(config-if)# ip variance
• Router(config-if)# ip maximum-paths 2
* Router(config-if)# ppp multilink

12 PPP uses several protocols for communication. Which of the following are options that the LCP protocol in the PPP architecture can provide? (Choose two.)
* testing the quality of the link
• routing packets between devices
• assigning individual station addresses
• configuring network layer protocols
• negotiating authentication options

13 How did Cisco alter the HDLC encapsulation to allow a single link to carry multiple protocols?
• split the transmissions into multiple channels each carrying a single protocol
• identified the protocol in the FCS field
• compressed the datagrams differently for each protocol
* added a type field to identify the protocol

14 Which of the following is an advantage of using time-division multiplexing (TDM) for transmitting data? (Choose two.)
• It allows a single source to transmit over multiple data channels.
* Multiple sources can transmit over a single channel.
* Original data streams must be reconstructed at the destination.
• TDM relies on Layer 3 protocols to operate.

15

What can be concluded from the output shown in the graphic? (Choose three.)
• A two-way handshake is occuring.
* The LCPs were already negotiated.
* The router can begin NCP negotiations.
• The debug ppp negotiation command was executed.
* The debug ppp authentication command was executed.

16

Which command was used to display the partial output shown in the graphic?
• show ppp traffic
• show lcp traffic
* debug ppp negotiation
• debug ppp authentication

17 How is the MD5 function valuable in authentication? (Choose two.)
* uses a one-way hash function
• authentication occurs more rapidly
* challenges are unique
• the remote router assumes control of frequency of challenge
the remote router assumes control of timing of challenge

18 What are three features of the CHAP protocol? (Choose three.)
* exchanges a random challenge number during the session to verify identity
• sends authentication password to verify identity
* prevents transmission of login information in plain text
* disconnects the PPP session if authentication fails
• initiates a two-way handshake

19 Which of the following describe functions of the Point-to-Point protocol with regards to the OSI model? (Choose three.)
• PPP uses Layer 3 of the OSI model to establish and maintain a session between devices.
• PPP operates at all layers of the OSI model.
* PPP uses the data link layer to configure such options as error detection and compression.
* PPP provides a mechanism to multiplex several network layer protocols.
• PPP uses Network Control Protocols (NCP) to test and maintain connectivity between devices.
* PPP can be configured on both synchronous and asynchronous serial interfaces.

20 Which advantage does the multilink option provide when using PPP?
* Data transmission has load balancing possibilities.
• Interfaces can be configured using both HDLC and PPP.
• More than one authentication method can be used.
• More than one compression protocol can be configured.