New CCNA WAN Lab Question.
This is an Updated real CCNA exam question (November 2013). You might see a different IP addressing, VLAN configuration and Port allocation and Configurations.
As usual, take time to read through the question so as to clearly understand what Cisco want you to do.
Note: This WAN Lab are used for demonstration only,you will see different IP addressing, configuration and Port allocation in the real CCNA exam. But it all works the same way if you could just grasp the technique.
Question 1:
Refer to the exhibit. Which statement describes DLCI 17?
DLCI
A: DLCI 17 describes the ISDN circuit between R2 and R3.
B: DLCI 17 describes a PVC on R2. It cannot be used on R3 or R1.
C: DLCI 17 is the Layer 2 address used by R2 to describe a PVCto R3.
D: DLCI 17 describes the dial-up circuit from R2 and R3 to theservice provider.
Answer: C
Brief explanation:
Virtual circuits (VC)s are identified by DLCIs. DLCI values typically are assigned by the Frame Relay service provider. Frame Relay DLCIs have local significance. A DLCI identifies a VC to the equipment at an endpoint. A DLCI has no significance beyond the single link. Two devices connected by a VC may use a different DLCI value to refer to the same connection.
Question 2:
Refer to the exhibit.
FRAME RELAY TROUBLESHOOTIN
The Frame Relay network in the diagram is not functioning properly. What is the cause of the problem?
A: The Gallant router has the wrong LMI type configured
B: Inverse ARP is providing the wrong PVC information to the Gallant router
C: The S3 interface of the Steele router has been configuredwith the frame-relay encapsulation ietf command
D: The frame-relay map statement in the Attalla router for the PVC to Steele is not correct
E: The IP address on the serial interface of the Attalla router is configured incorrectly
Correct Answer: D
Explanation:
The show frame relay map on Attalla router displays a deleted status which means that the map statement for the PVC from Attalla to Steele (IP address 172.31.31.62 dlci 509) is incorrect. Incorrect DLCI assignments normally shows as "deleted" in the frame relay maps.
Question 3:
What can a network administrator utilize by using PPP Layer 2 encapsulation?(Choose three.)
A: VLAN support
B: compression
C: authentication
D: sliding windows
E: multilink support
F: quality of service
Correct Answers: B C E
Read more on PPP here
Question 4:
Which of the following are key characteristics of PPP? (Choose three.)
A: can be used over analog circuits
B: maps Layer 2 to Layer 3 address
C: encapsulates several routed protocols
D: supports IP only
E: provides error correction
Correct Answers: A C E
Related Topic on PPP
Question 5:
How should a router that is being used in a Frame Relay network be configured to avoid split horizon issues from preventing routing updates?
A: Configure a separate sub-interface for each PVC with a unique DLCI and subnet assigned to the sub-interface
B: Configure each Frame Relay circuit as a point-to-point line to support multicast and broadcast traffic
C: Configure many sub-interfaces on the same subnet
D: Configure a single sub-interface to establish multiple PVCconnections to multiple remote router interfaces
Correct Answer: A
Explanation:
Study the figure below:
Frame Relay Subinterfaces
In the figure above, router R1 has two point-to-point Subinterfaces. The se0.1 subinterface connects to router R3 and the se0.2 subinterface connects to router R2.
Each subinterface is on a different subnet. By using Frame Relay subinterfaces, this ensures that a single physical interface is treated as multiple virtual interfaces to overcome split horizon rules. Packets received on one virtual interface can be forwarded to another virtual interface, even if they are configured on the same physical interface.
If you can recall that split horizon is a technique used to prevent a routing loop in networks using distance vector routing protocols. Split horizon updates reduce routing loops by preventing a routing update received on one interface to be forwarded out the same interface.
Question 6:
Which of the following describes the roles of devices in a WAN?(Choose three.)
CSC/DSU EXPLAINED
A: A CSU/DSU terminates a digital local loop
B: A modem terminates a digital local loop
C: A CSU/DSU terminates an analog local loop
D: A modem terminates an analog local loop
E: A router is commonly considered a DTE device
F: A router is commonly considered a DCE device
Correct Answers: A D E
Explanation:
WAN is to connect two or more DTE (router) networks together through a DCE(frame Relay switch, CSU/DSU) network. The CSU/DSU on the network provides clocking to the DTE-connected interface (router).
Question 7:
The command frame-relay map ip 10.126.16.9 102 broadcast was entered on the router.Which of the following statements is true concerning this command?
A: This command should be executed from the global configuration mode.
B: The IP address 10.121.16.8 is the local router port used to forward data.
C: 102 is the remote DLCI that will receive the information.
D: This command is required for all Frame Relay configurations.
E: The broadcast option allows packets, such as RIP updates, to be forwarded across the PVC.
Correct Answers: E
Explanation:
The command frame-relay map ip 10.126.16.9 102 broadcast maps IP 10.126.16. 102 to the local DLCI102. the "broadcast" keyword enables the Frame Relay network functions as broadcast network, Frame Relay, ATM, and X.25 are non-broadcast multiple access (NBMA) networks. Because NBMA does not support broadcast traffic, using the broadcast keyword is a simplified way to forward routing updates. The broadcast keyword allows broadcasts and multicasts over the PVC and, in effect, turns the broadcast into a unicast so that the other node gets the routing updates.
Question 8:
A default Frame Relay WAN is classified as what type of physicalnetwork?
A: point-to-point
B: broadcast multi-access
C: nonbroadcast multi-access
D: nonbroadcast multipoint
E: broadcast point-to-multipoint
Correct Answer: C
Explanation:
FrameRelay, ATM, and X.25 are non-broadcast multiple access (NBMA) networks. NBMA networks allow only data transfer from one computer to another over a VC or across a switching device. NBMA networks do not support multicast or broadcast traffic,
Question 9:
Refer to the exhibit. What is the meaning of the term dynamic as displayed in the output of the show frame-relay map command shown?
Frame Relay Map
A: The Serial0/0 interface is passing traffic.
B: The DLCI 100 was dynamically allocated by the router
C: The Serial0/0 interface acquired the IP address of 172.16.3.1from a DHCP server
D: The DLCI 100 will be dynamically changed as required to adaptto changes in the Frame Relay cloud
E: The mapping between DLCI 100 and the end station IP address172.16.3.1 was learned through Inverse ARP
Correct Answer: E
Explanation:
The term dynamic indicates that the DLCI value and the remote router IP address 172.16.3.1 are learned via the Inverse ARP process. The Inverse Address Resolution Protocol (ARP) obtains Layer 3 addresses of other stations from Layer 2 addresses, such as the DLCI in Frame Relay networks. It is primarily used in Frame Relay and ATM networks,
Question 10.
Which three Layer 2 encapsulation types would be used on a WAN rather than a LAN? (Choose three)
A: HDLC
B: Ethernet
C: Token Ring
D: PPP
E: FDDI
F: Frame Relay
Correct Answer: A D F
HDLC, PPP and Frame Relay are the default layer 2 encapsulations on a WAN.
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