Cisco CCNA 4 Exam 2 answer
1 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.
2 Which of the following are disadvantages of circuit-switched networks? (Choose two.)
Data is subject to unpredictable delays while it waits for other subscribers to transmit data.
* The connection capacity is used inefficiently due to irregular traffic bursts.
Data delivery is less reliable because only connectionless delivery methods are used.
* Circuit-switched networks are more expensive for data traffic.
Circuit-switched networks are less expensive for 24/7 data traffic.
3 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
4 Which of the following is commonly used as Data Terminal Equipment?
ISDN
* modem
router
CSU/DSU
5 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
6 On which of the following are most Layer 2 WAN encapsulations based?
IP
PPP
* HDLC
SLIP
HSSI
CSU
7 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
8 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
9 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.
10 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
11 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
12 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
13 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
14 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.
15 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
16 A company only requires a WAN connection to transfer sales data from individual stores to the home office. All transfers will occur after business hours. They estimate they will never need a connection faster than 56 kbps. Which type of connection is best for this company?
ATM
ISDN
* analog dialup
T1 Leased Line
17 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.
Cisco CCNA 4 Exam 3 answer
Cisco CCNA 4 Exam 3 answer
1 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. ¡Ì
*PPP provides a mechanism to multiplex several network layer protocols. ¡Ì
PPP uses Network Control Protocols (NCP) to test and maintain connectivity between devices.
*PPP can be configured on both synchronous and asynchronous serial interfaces. ¡Ì
2 What can be concluded from the output shown in the graphic? (Choose three.)
A two-way handshake is occuring.
*The LCPs were already negotiated. ¡Ì
*The router can begin NCP negotiations. ¡Ì
The debug ppp negotiation command was executed.
*The debug ppp authentication command was executed. ¡Ì
3 Which command specifies a link quality over a PPP link?
ppp link 50
ppp link quality 60
ppp percentage 80
*ppp quality 90 ¡Ì
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 authentication protocol can be spoofed to allow playback attacks?
MD5
CHAP
*PAP
NCP
6 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. ¡Ì
*Original data streams must be reconstructed at the destination. ¡Ì
TDM relies on Layer 3 protocols to operate.
7 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 ¡Ì
send hostname and password information between the two routers
8 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
9 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
10 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
11 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
12 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.
13 Which of the following describes the CHAP protocol? (Choose three.)
* exchanges a random challenge number during the session to verfiy 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
14 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
15 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
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 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.
18 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
19 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
20 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.)
* Serial0/0 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.
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