3.1 CCNA 4 - Final

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

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