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QUESTION 736
Two Certifyme routers are connected via a PPP connection. Which of the following are key characteristics of
this PPP connection? (Choose three)
A. PPP can be used over analog circuits
B. PPP encapsulates several routed protocols
C. PPP maps Layer 2 to Layer 3 address
D. PPP provides error correction
E. PPP supports IP only
F. PPP provides encryption services

Answer: ABD

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:

QUESTION 737
In a point to point connection between two Certifyme offices, which PPP subprotocol negotiates authentication
options?
A. NCP
B. ISDN
C. SLIP
D. LCP
E. DLCI

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
LCP: A method of establishing, configuring, maintaining, and terminating the point-to-point connection.
Link-establishment phase LCP packets are sent by each PPP device to configure and test the link. These
packets contain a field called the Configuration Option that allows each device to see the size of the data,
compression, and authentication. If no Configuration Option field is present, then the default configurations are
used.

QUESTION 738
Routers CM1 and CM2 are connected via a private line using PPP. On this link, which of the following options
lists the steps in PPP session establishment in the correct order?
A. network layer protocol phase, optional authentication phase, link establishment phase
B. link establishment phase, network layer protocol phase, optional authentication phase
C. optional authentication phase, network layer protocol phase, link establishment phase
D. link establishment phase, optional authentication phase, network layer protocol phase
E. network layer protocol phase, link establishment phase, optional authentication phase
F. optional authentication phase, link establishment phase, network layer protocol phase
G. None of the above

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
According to the related RFC on CHAP: In order to establish communications over a point-to-point link, each
end of the PPP link must first send LCP packets to configure the data link during Link Establishment phase.
After the link has been established, PPP provides for an optional Authentication phase before proceeding to
the Network-Layer Protocol phase.
Reference: http://www.ietf.org/rfc/rfc1994.txt

QUESTION 733
Two Certifyme routers are connected as shown below:
Certifyme1 command output exhibit:
The two Certifyme routers shown above are the only Cisco devices on the network.
The serial network between the two devices has a mask of 255.255.255.252 (/30).
Given the output that is shown, what three statements are true of these devices? (Choose three)
A. The Certifyme1 serial address is 10.1.1.1.
B. The CDP information was received on port Serial0/0 of the Certifyme1 router.
C. The CDP information was sent by port Serial0/0 of the Certifyme2 router.
D. The Certifyme2 router is a Cisco 2610.
E. The Certifyme1 router is a Cisco 2610.
F. The Certifyme1 serial address is 10.1.1.2.
G. CDP is not enabled on Certifyme2

Answer: ABD

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:

QUESTION 734
A point to point leased line connecting routers Certifyme1 and Certifyme2 is installed as shown below:
The two serially connected routers can’t communicate. Can you identify the fault on router Certifyme2?
A. Link reliability is insufficient
B. IPCP is not open
C. Incorrect subnet mask
D. Incompatible encapsulation
E. Bandwidth allocation is too low
F. Incomplete IP address
G. None of the above

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
HDLC and PPP configuration is straightforward. You just need to be sure to configure the same WAN data-link
protocol on each end of the serial link. Otherwise, the routers will misinterpret the incoming frames, because
each WAN data-link protocol uses a different frame format. The routers must match at each end of the private
leased line link.
Reference: CCNA Self-Study CCNA ICND exam certification Guide (Cisco Press, ISBN 1-58720X) Page 310.
Section 5: Describe VPN technology (including: importance,
benefits, role, impact, components) (0 questions)
Section 6: Configure and verify a PPP connection between Cisco routers (10 questions)

QUESTION 735

Two Certifyme buildings are connected together as shown below:
The Certifyme network administrator is in a campus building distant from Building B. The WANRouter is hosting
a newly installed WAN link on interface S0/0. The new link is not functioning and the administrator needs to
determine if the correct cable has been attached to the S0/0 interface. How can the administrator accurately
verify the correct cable type on S0/0 in the most efficient manner?
A. Physically examine the cable between Certifyme2 S0/0 and the DCE
B. Telnet to Certifyme2 and execute the command show interface S0/0
C. Telnet to Certifyme2 and execute the command show controller S0/0
D. Telnet to Certifyme2 and execute the command show processes S0/0
E. None of the above

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:

QUESTION 730
Refer to the Certifyme frame relay exhibit below:
In this frame relay network, which IP addresses would be assigned to the CM1, CM2, and CM3 interfaces when
using point-to-point PVCs?
A. DLCI 16: 192.168.10.1 /24 DLCI 17: 192.168.10.1 /24 DLCI 99: 192.168.10.2 /24 DLCI 28:
192.168.10.3 /24
B. DLCI 16: 192.168.10.1 /24 DLCI 17: 192.168.11.1 /24 DLCI 99: 192.168.12.1 /24 DLCI 28:
192.168.13.1 /24
C. DLCI 16: 192.168.10.1 /24 DLCI 17: 192.168.10.2 /24 DLCI 99: 192.168.10.3 /24 DLCI 28:
192.168.10.4 /24
D. DLCI 16: 192.168.10.1 /24 DLCI 17: 192.168.11.1 /24 DLCI 99: 192.168.10.2 /24 DLCI 28:
192.168.11.2 /24

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
With Point to point PVC’s, two subinterfaces would be created on router CM2, one for each connection to the
remote locations. In this network, the connection to CM1 would require one IP subnet, and the connection to
router CM3 would require another. These two subnets must be separated, as each subinterface requires a
distinct IP network. Only choice D correctly shows one IP subnet allocated to the CM1-CM2 network, and one
for the CM2-CM3 connection.
Section 4: Troubleshoot WAN implementation issues (4 questions)

QUESTION 731
What is the advantage of using a multipoint interface instead of point-to-point subinterfaces when configuring a
Frame Relay hub in a hub-and-spoke topology?
A. It avoids split-horizon issues with distance vector routing protocols.
B. IP addresses can be conserved if VLSM is not being used for subnetting.
C. A multipoint interface offers greater security compared to point-to-point subinterface
configurations.
D. The multiple IP network addresses required for a multipoint interface provide greater addressing flexibility
over point-to-point configurations.
E. None of the above

Answer: B

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Frame Relay supports two types of interfaces: point-to-point and multipoint. The one you choose determines
whether you need to use the configuration commands that ensure IP address to data-link connection identifier
(DLCI) mappings. After configuring the PVC itself, you must tell the router which PVC to use in order to reach a
specific destination.
Let’s look at these options:
1. Point-to-point subinterface – With point-to-point subinterfaces, each pair of routers has
its own subnet. If you put the PVC on a point-to-point subinterface, the router assumes that there is only one
point-to-point PVC configured on the subinterface. Therefore, any IP packets with a destination IP address in
the same subnet are forwarded on this VC.
This is the simplest way to configure the mapping and is therefore the recommended method. Use the
frame-relay interface-dlci command to assign a DLCI to a specified Frame Relay subinterface.
2. Multipoint networks – Multipoint networks have three or more routers in the same subnet. If you put the PVC
in a point-to-multipoint subinterface or in the main interface (which is multipoint by default), you need to either
configure a static mapping or enable inverse Address Resolution Protocol (ARP) for dynamic mapping.

QUESTION 732
Part of the Certifyme network is shown below:
After the router interfaces shown in the diagram above have been configured, it is discovered that hosts in the
Branch LAN cannot access the Internet.
Further testing reveals additional connectivity issues. What will fix this problem?
A. Change the address of the Branch router LAN interface.
B. Change the address of the Branch router WAN interface.
C. Change the subnet mask of the HQ router LAN interface.
D. Change the address of the HQ router LAN interface.
E. Change the address of the HQ router interface to the Internet.
F. Change the subnet mask of the HQ router interface to the Internet.
G. None of the above

Answer: B

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
The serial line connection between the Branch office and the HG office should have interfaces that belong in
the same subnet. Based on the diagram above, the WAN interface of the Branch router is configured with an
IP address that is in a different IP network than the serial interface of the HG router. As it is set up currently, no
traffic will pass from the Branch router to the HG until these two interfaces are in the same subnet.

QUESTION 727
While troubleshooting an issue with your frame relay network, you issue the “show frame pvc” command as
shown in the exhibit below:
You’re a network administrator at a Certifyme branch office, that’s connected to the central headquarters by
means of Frame Relay. You’ve been getting complaints that the connection has suddenly become slow, so you
make the assumption that there’s too much traffic going through the link.
Taking into consideration the above output from the ‘show frame relay pvc’ command; which command output
value is indicating that there’s congestion between the local router and the corporate site?
A. in DE packets 0
B. last time PVC status changed 00:25:40
C. in BECN packets 192
D. DLCI = 100
E. in FECN packets 147

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
BECN stands for Backward Explicit Congestion Notification. The BECN tells the transmitting device that the
Frame Relay network is congested and that it should “back off” to allow better throughput. BECN and FECN go
hand to hand together, but since the question specifically asks for what’s indicating congestion between the
local router and corporate site, BECN is correct.

QUESTION 728
You are attempting to troubleshoot a frame relay problem you are having within the Certifyme network, but you
are unsure where to start. You begin by entering the command:
Router# show frame-relay ?
Which three options will you be prompted for? (Select three answers choices)
A. dlci
B. clients
C. pvc
D. neighbors
E. lmi
F. map

Answer: CEF

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
The valid options for, ‘show frame-relay’ are: show frame-relay map, show frame-relay lmi, & show frame-relay
pvc. In the Cisco IOS, if you don’t type in a command specific enough, it will prompt you to select an option.
Incorrect Answers:
A, B, D. Show frame-relay dlci, show frame-relay clients, and show frame-relay neighbors are all invalid
commands.

QUESTION 729
In the example above, A Certifyme router interface is being configured for Frame Relay. However, as the exhibit
shows, the router will not accept the command to configure the LMI type. What is the problem?
A. The interface does not support Frame Relay connections.
B. The interface does not have an IP address assigned to it yet.
C. The interface requires that the no shutdown command be configured first.
D. The interface requires that the encapsulation frame-relay command be configured first.

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Before entering LMI type in interface, you should type the encapsulation frame-relay command. By default,
serial interfaces use HDLC encapsulation, where the LMI type is not a configurable option as HDLC does not
understand the concept of LMI.
See the sample Configuration steps:
Router(config-if)#encapsulation frame-relay {cisco | ietf} Router(config-if)#frame-relay lmi-type {ansi | cisco |
q933a}
QUESTION 48
Refer to

QUESTION 724
The Certifyme international frame relay network is shown below:
The Frame Relay circuit between Mexico and Canada is experiencing congestion.
Which types of notification are used to alleviate the congestion? (Choose three.)
A. FECN
B. CIR
C. BECN
D. DE
E. DLCI 100 is down
F. DLCI 200 is down

Answer: ACD

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
In a frame relay network, FECN (forward explicit congestion notification) is a header bit transmitted by the
source (sending) terminal requesting that the destination (receiving) terminal slow down its requests for data.
BECN (backward explicit congestion notification) is a header bit transmitted by the destination terminal
requesting that the source terminal send data more slowly. FECN and BECN are intended to minimize the
possibility that packets will be discarded (and thus have to be resent) when more packets arrive than can be
handled.
If the source terminal in a communications circuit generates frequent FECN bits, it indicates that the available
network bandwidth (at that time) is not as great as can be supported by the destination terminal. Likewise, if
the destination generates frequent BECN bits, it means the available network bandwidth (at that time) is not as
great as can be supported by the source. In either case, the root cause is lack of available bandwidth at the
times during which FECN or BECN bits are generated. This can occur because of outdated or inadequate
network infrastructure, heavy network traffic, high levels of line noise, or portions of the system going down.
Identifying and resolving these issues can improve overall network performance, especially when the system is
called upon to carry a large volume of traffic.
Discard Eligibility (DE) When there is congestion on the line, the network must decide which frames to discard
in order to free the line. Discard Eligibility provides the network with a signal to determine which frames to
discard. The network will discard frames with a DE value of 1 before discarding other frames.
The DE bit may be set by the user on some of its lower-priority frames. Alternatively, the network may set the
DE bit to indicate to other nodes that a frame should be preferentially selected for discard, if necessary.

QUESTION 725
Please study the exhibit carefully. What does the STATUS=ACTIVE refer to in the output of the show framerelay
pvc command shown above?
A. The PVC is experiencing congestion.
B. The Frame Relay switch is correctly programmed with the DLCI and is operational.
C. The router is actively broadcasting to establish a link to the Frame Relay switch.
D. The router is connected to the local Frame Relay switch, but not to the far end device.
E. None of the above

Answer: B

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
The Frame Relay switch uses LMI to report the status of configured PVCs. The three possible PVC states are
as follows:
Active state – Indicates that the connection is active and that routers can exchange data.
This is the state of an operational PVC.
Inactive state – Indicates that the local connection to the Frame Relay switch is working, but the remote router
connection to the Frame Relay switch is not working.
Deleted state – Indicates that no LMI is being received from the Frame Relay switch, or that there is no service
between the CPE router and Frame Relay switch.

QUESTION 726
Study the output script and the network topology exhibit below:
Certifyme1# show running-config

interface serial0/0
bandwidth 64
ip address 172.16.100.2 255.255.0.0
encapsulation frame-relay
frame-relay map ip 172.16.100.1 100 broadcast
The Router Certifyme1 in Hong Kong is connected to the router Certifyme2 in Tokyo via a new Frame Relay link.
However, Certifyme1 is unable to communicate with Certifyme2. Based on the above output, what do you
suspect as the underlying cause of this problem?
A. Bandwidth configuration incorrect
B. IP address not correct
C. Improper map statement
D. Improper LMI configuration
E. None of the above

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
From looking at the diagram you can see that Hong Kong’s DLCI is 100, while Tokyo’s DLCI is 200.
The Frame Relay map command is an interface configuration mode command that statically defines a mapping
between a network layer address and a DLCI.
Incorrect Answers:
A. The bandwidth statement is not used by the routers at a physical or data link layer, so this statement will not
have any impact on the function of the frame relay circuit.
B. We do not know what the IP address of the Tokyo side is, so this can not be assumed.
D. The default LMI type is Cisco, and since both routers in this network appear to be Cisco’s, we can assume
that this is acceptable.

QUESTION 721
Regarding Frame Relay Multipoint subinterfaces; which statement is true?
A. An IP address is required on the physical interface
B. All routers are required to be fully meshed
C. All routers must be in the same subnet to forward routing updates and broadcasts
D. Multipoint is the default configuration for Frame Relay subinterfaces
E. None of the above

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Unlike Frame Relay point-to-point connections, multipoint Frame Relay router interfaces must all be in the
same subnet. With multipoint, a single subinterface is used to establish multiple PVC connections to multiple
physical interfaces or subinterfaces on remote routers. In this case, all the participating interfaces are in the
same subnet, and each interface has its own local DLCI. Because the subinterface is acting like a regular
NBMA Frame Relay network in this environment, broadcast traffic is subject to the split horizon rule.
Incorrect Answers:
A. The IP address is required on the logical subinterface, not the physical interface.
B. It is never an absolute requirement for a frame relay network to be fully meshed. The vast majority of frame
relay networks are configured in a hub and spoke fashion, to avoid all of the charges associated with the
numerous PVC’s needed to be fully meshed.
D. Point to point is the default frame relay subinterface type.

QUESTION 722
The Certifyme Frame Relay network is displayed below:
In regard to router Certifyme1; what is the function of the Frame Relay DLCI?
A. Defines the signaling standard between Certifyme1 and Certifyme2.
B. Classifies the encapsulation used between Certifyme1 and Certifyme2.
C. Identifies the circuit between Certifyme2 and the frame switch.
D. Classifies the circuit between Certifyme1 and Certifyme2.
E. Defines the signaling standard between Certifyme1 and the frame switch.

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Certifyme1 sends frames with DLCI, and they reach the local switch. The local switch sees the DLCI field and
forwards the frame through the Frame Relay network until it reaches the switch connected to Certifyme2. The
Certifyme2′s local switch forwards the frame out of the access link to Certifyme2. DLCI information is considered
to be locally significant, meaning that the DLCI is used between the end router and the carrier’s local frame
relay switch.
Reference: CCNA Self-Study CCNA ICND exam certification Guide (Cisco Press, ISBN 1-58720X) Page 386
Incorrect Answers:
A, E. DLCI is used only as a circuit identifier (DLCI=Data Link Circuit Identifier), and not used for signaling.
B. The encapsulation options are not defined with DLCIs.
D. The DLCI information is considered to be locally significant, meaning that the DLCI is used between the end
router and the carrier’s local frame relay switch. The DLCI is not used end to end (router to router).

QUESTION 723
Your frame relay network uses DLCI information on each of the PVC’s. What is the purpose of them?
A. They determine the encapsulation type employed by the Frame Relay.
B. They identify the logical circuit between a local router and a Frame Relay WAN switch.
C. They represent the physical address of the router.
D. They represent the keepalives in the maintenance of PVC.

Answer: B

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Routers use the data-link connection identifier (DLCI) as the Frame Replay address, which identifies the VC
over which the frame should travel.
Data Link Connection Identifiers are the “hardware address” on a Frame Relay network.
They identify a routers PVC to the Frame Relay switch.
Incorrect Answers:
A. DLCI information is not used to determine the encapsulation of the frame relay circuit in any way.
C. A DLCI is used at layer two, but it is a separate identifier that is not related to the hardware MAC address of
any device.
D. The function of a keepalive is handled by LMI in a frame network, not the DLCI.
Reference:
CCNA Self-Study CCNA ICND exam certification Guide (Cisco Press, ISBN 1-58720X) page 377

QUESTION 718
In Frame Relay; what is the purpose of Inverse ARP? (Select only one answer choice)
A. It is used to map a known IP address to a MAC address
B. It is used to map a known DLCI to a MAC address
C. It is used to map a known MAC address to an IP address
D. It is used to map a known DLCI to an IP address
E. It is used to map a known MAC address to DLCI
F. None of the above

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Just as ARP resolves IP addresses to MAC addresses, Inverse ARP maps a known DLCI to an IP address.
Incorrect Answers:
A, C: ARP and Reverse ARP (RARP) are used for IP address/MAC address mappings.
B, E: DLCI do not have a need to discover the MAC address of a host, so a DLCI is never mapped to a MAC
address.

QUESTION 719
In regard to a default Frame-Relay data network, what kind of physical network is it classified as?
A. Point-to-point
B. Broadcast multi-access
C. Nonbroadcast multipoint
D. Nonbroadcast multi-access
E. Broadcast point-to-multipoint
F. None of the above

Answer: D

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Frame relay networks are considered to be NBMA networks. Frame Relay is a WAN protocol that operates at
the physical and data link layers of the Open System Interconnection (OSI) reference model. This protocol is
standardized by both the International Telecommunication Union Telecommunications Standardization Sector
(ITU-T) and American National Standards Institute (ANSI).
Frame Relay uses statistical multiplexing techniques to provide network access in a packet-switched network.
It is strictly a Layer 2 protocol suite. Being a Layer 2 protocol enables Frame Relay to offer higher performance
WAN applications (such as LAN interconnection) than the older protocols (such as X.25), which incorporated
Layer 3 functions. Given these performance benefits, Frame Relay is a popular WAN medium.
However, it has some limitations with regard to IP multicast. To illustrate, Frame Relay is a Layer 2
nonbroadcast multiaccess (NBMA) network protocol. IP multicast networks are designed to utilize the
capabilities of Layer 2 broadcast media such as on a LAN.

QUESTION 720
Which of the following statements correctly describes the characteristics of a Frame Relay point-to-point
subinterface? (Select two answer choices)
A. Needs to use Inverse ARP.
B. Maps a single IP subnet per DLCI.
C. Maps a single IP subnet across multiple DLCIs.
D. Resolves NBMA (non broadcast multi access) split horizon issues.
E. Requires use of the frame-relay map command.
F. None of the above

Answer: BD

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
B is correct because only one DLCI can be configured per point-to-point subinterface.
The command ‘frame-relay interface-dlci’ associates the selected point-to point subinterface with only one
DLCI.
Subinterfaces were originally created to take care of split-horizon issues from distance vector routing protocols
over non-broadcast multiple access networks, because split horizon prevents routing updates received on one
interface from retransmitting out onto the same interface. This is true even if the routing update is received on
one frame relay PVC destined out to another frame relay PVC! By partitioning the frame relay network into
numerous point-to point networks using subinterfaces; each new point-to-point subnetwork gets their own
network number assigned. Therefore, the routed protocol views each subnetwork as if it was located on a
separate interface.
Incorrect Answers:
A. Since only one DLCI is assigned per subnet in a logical point to point interface, there is no need for Inverse
ARP, since both the DLCI and IP addresses are already known.
C. The IP subnet is mapped across a single virtual circuit, so only one DLCI is mapped per subinterface.
E. This command would be needed when multiple virtual circuits are being configured on one physical
interface. When logical subinterfaces are used, the “frame-relay interface-dlci” command is used, not this
command.
Reference: http://www.ciscopress.com/articles/article.asp?p=170741&seqNum=6

QUESTION 715
You are in the midst of configuring a router for a Frame Relay network. What could you do to prevent split
horizon problems? (Select all that apply)
A. Configure a separate sub-interface for each PVC. Assign a unique DLCI and subnet to each sub-interface.
B. Configure each Frame Relay circuit as a point-to-point line to support multicast and broadcast traffic.
C. Configure one sub-interface to disperse into multiple PVC connections to multiple remote router interfaces.
D. Configure as many as possible sub-interfaces on the same subnet.
E. Use the “no ip split-horizons” command on the physical interface.

Answer: AE

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
The best solution is to configure subinterfaces for each virtual connection, because the individual virtual circuits
can be maintained and split horizon can remain on.Routing update information that is received through one
subinterface can be propagated to other subinterfaces, because each sub-interface is treated as a completely
separate interface.
Configuring Frame Relay subinterfaces ensures that a single physical interface is treated as multiple virtual
interfaces. This capability allows you to overcome split horizon rules so packets received on one virtual
interface can be forwarded to another virtual interface, even if they are configured on the same physical
interface. Another alternative to using sub-interfaces is to simply disable the split horizon mechanism as shown
in choice E.
Reference: http://www.cisco.com/warp/public/116/fr_faq.html

QUESTION 716
A new frame-relay network is being implemented and inverse ARP does not appear to be operating correctly.
Which alternative command can be used to provide connectivity?
A. frame-relay arp
B. frame-relay map
C. frame-relay interface-dlci
D. frame-relay lmi-type
E. frame-relay pvc

Answer: B

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
When using dynamic address mapping, Inverse ARP requests a next-hop protocol address for each active
PVC. Once the requesting router receives an Inverse ARP response, it updates its DLCI-to-Layer 3 address
mapping table. Dynamic address mapping is enabled by default for all protocols enabled on a physical
interface. If the Frame Relay environment supports LMI autosensing and Inverse ARP, dynamic address
mapping takes place automatically. Therefore, no static address mapping is required.
If the environment does not support LMI autosensing and Inverse ARP, a Frame Relay map must be manually
configured. Use the frame-relay map command to configure static address mapping. Once a static map for a
given DLCI is configured, Inverse ARP is disabled on that DLCI.

QUESTION 717
Which of the following Frame-Relay encapsulation commands would you use, if you had to connect your Cisco
router to a non-Cisco router?
A. TesCMRouter(config-if)# Encapsulation frame-relay dot1q
B. TesCMRouter(config-if)# Encapsulation frame-relay aal5snap
C. TesCMRouter(config-if)# Encapsulation frame-relay ietf
D. TesCMRouter(config-if)# Encapsulation frame-relay isl
E. None of the above

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
In general, the IETF Frame Relay encapsulation should be used when connecting a Cisco router to non-Cisco
equipment across a Frame Relay network. The IETF Frame Relay encapsulation allows interoperability
between equipment from multiple vendors.
Both Cisco and IETF encapsulations for Frame Relay can be configured on a per-virtual-circuit (VC) basis.
This gives greater flexibility when configuring Frame Relay in a multi-vendor environment. A user can specify
the Frame Relay encapsulation types to be used on different virtual circuits configured under the same
physical interface.
Incorrect Answers:
A, D: 802.1Q and ISL are trunking encapsulation types and have nothing to do with frame relay.
B. AAL 5 SNAP is an ATM encapsulation and is not related to frame relay.

QUESTION 712
CM1 is a Cisco router was providing Frame Relay connectivity at a remote Certifyme branch site. This router
was replaced with a different vendor’s frame relay router.
Connectivity is now down between the central and remote site. What is the most likely cause of the problem?
A. Mismatched encapsulation types
B. Incorrect IP address mapping
C. Mismatched LMI types
D. Incorrect DLCI
E. None of the above

Answer: A

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:

QUESTION 713
The Certifyme frame relay network is shown below:
In this network, which statement describes DLCI 17?
A. DLCI 17 is the Layer 2 address used by CM2 to describe a PVC to CM3.
B. DLCI 17 describes the ISDN circuit between CM2 and CM3.
C. DLCI 17 describes a PVC on CM2. It cannot be used on CM3 or CM1.
D. DLCI 17 describes the dial-up circuit from CM2 and CM3 to the service provider.
E. None of the above

Answer: A

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
DLCI-Data Link Connection Identifier Bits: The DLCI serves to identify the virtual connection so that the
receiving end knows which information connection a frame belongs to. Note that this DLCI has only local
significance. Frame Relay is strictly a Layer 2 protocol suite

QUESTION 714
When configuring Frame Relay using point-to-point subinterfaces, which of the following must not be
configured? (Select one)
A. The local DLCI on each subinterface of the Frame Relay.
B. The Frame Relay encapsulation on the physical interface.
C. An IP address on the physical interface.
D. The subinterface type as point-to-point
E. None of the above

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Frame Relay does not require IP addresses on physical interfaces. A subnet address is usually assigned to
each point-to-point connection. Therefore, only one DLCI can be configured per point-to-point subinterface. On
point-to-point subinterfaces, the destination is identified and configured with the frame-relay interface-dlci
command beginning in interface configuration mode. When configured on a point-to-point subinterface, the
command associates the selected point-to-point subinterface with a DLCI. The command also allows users to
select the type of Frame Relay encapsulation to be used on the specific VC. The command can be executed
without specifying the Frame Relay encapsulation type to be used. By default, the Cisco Frame Relay
encapsulation type will be used.

QUESTION 709
You are a technician at Certifyme. Your newly appointed Certifyme trainee is setting up a new frame relay
connection to a remote branch and wants to know what the valid options for frame relay LMI types are.
What would your reply be? (Choose all that apply.)
A. EIA/TIA
B. Q.932
C. Q.933 A
D. IEEE
E. IETF
F. Cisco
G. ANSI

Answer: CFG

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
The following describe the various frame relay LMI options:
Name Document IOS LMI-Type * Cisco Proprietary cisco * ANSI T1.617 Annex D ansi * ITU Q.933. Annex A
q.933a
You can set one of three types of LMIs on our devices: ANSI T1.617 Annex D, Cisco, and ITU-T Q.933 Annex
A. To do so, use the following commands beginning in interface configuration mode:
Reference:
CCNA Self-Study CCNA ICND exam certification Guide (Cisco Press, ISBN 1-58720X) Page 382

QUESTION 710
How should router CM1, which will be used in the Certifyme Frame Relay network, be configured to avoid split
horizon issues from preventing routing updates?
A. Configure a single sub-interface to establish multiple PVC connections to multiple remote router interfaces.
B. Configure a separate sub-interface for each PVC with a unique DLCI and subnet assigned to the subinterface.
C. Configure many sub-interfaces on the same subnet.
D. Configure each Frame Relay circuit as a point-to-point line to support multicast and broadcast traffic.
E. None of the above

Answer: B

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference:
Explanation:
Point-To-Point Subinterfaces:
The concept of subinterfaces was originally created in order to better handle issues caused by split-horizon
over Non-Broadcast Multiple Access (NBMA) networks (e.g. frame relay, X.25) and distance-vector based
routing protocols (e.g. IPX RIP/SAP, AppleTalk).
Split-horizon dictates that a routing update received on an interface cannot be retransmitted out onto the same
interface. This rule holds even if the routing update was received on one frame relay PVC and destined to
retransmit out onto another frame relay PVC. Referring to figure 2, this would mean that sites B and C can
exchange routing information with site A, but would not be able to exchange routing information with each
other. Split-horizon does not allow Site A to send routing updates received from Site B on to Site C and vice
versa.
Note: For TCP/IP, Cisco routers can disable split-horizon limitations on all frame relay interfaces and multipoint
subinterfaces and do this by default. However, split-horizon cannot be disabled for other protocols like IPX and
AppleTalk. These other protocols must use subinterfaces if dynamic routing is desired.
By dividing the partially-meshed frame relay network into a number of virtual, point-to-point networks using
subinterfaces, the split-horizon problem can be overcome.
Each new point-to-point subnetwork is assigned its own network number. To the routed protocol, each
subnetwork now appears to be located on separate interfaces (Figure 3).
Routing updates received from Site B on one logical point-to-point subinterface can be forwarded to site C on a
separate logical interface without violating split horizon.

QUESTION 711
Router CM1 is being used in the Certifyme frame relay network. When this frame relay router is connected to a
WAN link using a serial DTE interface, how is the interface clock rate determined?
A. It is supplied by the far end router.
B. It is supplied by the Layer 1 bit stream timing.
C. It is supplied by the CSU/DSU.
D. It is determined by the clock rate command.
E. None of the above

Answer: C

Section: IMPLEMENT AND VERIFY WAN LINKS
Explanation/Reference: