Introduction to Networks Version 6 – ITN Practice Final

Introduction to Networks (Version 6.00) – ITN Practice Final

QUESTION 1

Which statement is correct regarding the operation of DHCP?

A.A DHCP client uses a ping to detect address conflicts.
B.A DHCP server uses a gratuitous ARP to detect DHCP clients.
C.A DHCP client uses a gratuitous ARP to detect a DHCP server.
D.If an address conflict is detected, the address is removed from the pool and an administrator must
resolve the conflict.
E.If an address conflict is detected, the address is removed from the pool for an amount of time
configurable by the administrator.
F. If an address conflict is detected, the address is removed from the pool and will not be reused until the server is rebooted.

Correct Answer: D
Section: (none)
Explanation

Explanation/Reference:
Explanation:
An address conflict occurs when two hosts use the same IP address. During address assignment, DHCP
checks for conflicts using ping and gratuitous ARP. If a conflict is detected, the address is removed from the
pool. The address will not be assigned until the administrator resolves the conflict.
http://www.cisco.com/en/US/docs/ios/12_1/iproute/configuration/guide/1cddhcp.html

QUESTION 2

Refer to the exhibit. Statements A, B, C, and D of ACL 10 have been entered in the shown order and
applied to interface E0 inbound, to prevent all hosts (except those whose addresses are the first and last IP
of subnet 172.21.1.128/28) from accessing the network. But as is, the ACL does not restrict anyone from
the network. How can the ACL statements be re-arranged so that the system works as intended?

A.ACDB
B.BADC
C.DBAC
D.CDBA

Correct Answer: D
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Routers go line by line through an access list until a match is found and then will not look any further, even if
a more specific of better match is found later on in the access list. So, it it best to begin with the most
specific entries first, in this cast the two hosts in line C and D. Then, include the subnet (B) and then finally
the rest of the traffic (A).

QUESTION 3

The output of the show frame-relay pvc command shows “PVC STATUS = INACTIVE”. What does this mean?

A.The PVC is configured correctly and is operating normally, but no data packets have been detected for
more than five minutes.
B.The PVC is configured correctly, is operating normally, and is no longer actively seeking the address of
the remote router.
C.The PVC is configured correctly, is operating normally, and is waiting for interesting traffic to trigger a
call to the remote router.
D.The PVC is configured correctly on the local switch, but there is a problem on the remote end of the
PVC.
E.The PVC is not configured on the local switch.

Correct Answer: D
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The PVC STATUS displays the status of the PVC. The DCE device creates
and sends the report to the DTE devices. There are 4 statuses:
+ ACTIVE: the PVC is operational and can transmit data + INACTIVE: the connection from the local router
to the switch is working, but the connection to the remote router is not available + DELETED: the PVC is not
present and no LMI information is being received from the Frame Relay switch
+ STATIC: the Local Management Interface (LMI) mechanism on the interface is disabled (by using the “no
keepalive” command). This status is rarely seen so it is ignored in some books.

QUESTION 4

Which command is used to enable CHAP authentication, with PAP as the fallback method, on a serial interface?

A.Router(config-if)# ppp authentication chap fallback ppp
B.Router(config-if)# ppp authentication chap pap
C.Router(config-if)# authentication ppp chap fallback ppp
D.Router(config-if)# authentication ppp chap pap

Correct Answer: B
Section: (none)
Explanation

Explanation/Reference:
Explanation:
This command tells the router to first use CHAP and then go to PAP if CHAP isn’t available.

QUESTION 5

Which protocol is an open standard protocol framework that is commonly used in VPNs, to
provide secure end-to-end communications?

A.RSA
B.L2TP
C.IPsec
D.PPTP

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
IPSec is a framework of open standards that provides data confidentiality, data integrity, and data
authentication between participating peers at the IP layer. IPSec can be used to protect one or more data
flows between IPSec peers.

QUESTION 6

At which layer of the OSI model does PPP perform?

A.Layer 2
B.Layer 3
C.Layer 4
D.Layer 5

Correct Answer: A
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams
over point-to-point links. PPP was originally emerged as an encapsulation protocol for transporting IP traffic
between two peers. It is a data link layer protocol (layer 2 in the OSI model )

QUESTION 7

The command frame-relay map ip 10.121.16.8 102 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 Answer: E
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Broadcast is added to the configurations of the frame relay, so the PVC supports broadcast, allowing the
routing protocol updates that use the broadcast update mechanism to be forwarded across itself.

QUESTION 8

Which two options are valid WAN connectivity methods? (Choose two.)

A.PPP
B.WAP
C.DSL
D.L2TPv3
E.Ethernet

Correct Answer: AC
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams
over point-to-point links. PPP was originally emerged as an encapsulation protocol for transporting IP traffic
between two peers. It is a data link layer protocol used for WAN connections.
DSL is also considered a WAN connection, as it can be used to connect networks, typically when used with VPN technology.

QUESTION 8

Which Layer 2 protocol encapsulation type supports synchronous and asynchronous circuits and has builtin security mechanisms?

A.HDLC
B.PPP
C.X.25
D.Frame Relay

Correct Answer: B
Section: (none)
Explanation

Explanation/Reference:
Explanation:
PPP: Provides router-to-router and host-to-network connections over synchronous and asynchronous
circuits. PPP was designed to work with several network layer protocols, including IP. PPP also has built-in
security mechanisms, such as Password Authentication Protocol (PAP) and Challenge Handshake
Authentication Protocol (CHAP).

QUESTION 9

Which encapsulation type is a Frame Relay encapsulation type that is supported by Cisco routers?

A.IETF
B.ANSI Annex D
C.Q9333-A Annex A
D.HDLC

Correct Answer: A
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Cisco supports two Frame Relay encapsulation types: the Cisco encapsulation and the IETF Frame Relay
encapsulation, which is in conformance with RFC 1490 and RFC 2427. The former is often used to connect
two Cisco routers while the latter is used to connect a Cisco router to a non-Cisco router. You can test with
your Cisco router when typing the command Router(config- if)# encapsulation frame-relay ? on a WAN link.
Below is the output of this command (notice Cisco is the default encapsulation so it is not listed here, just
press Enter to use it).

Note: Three LMI options are supported by Cisco routers are ansi, Cisco, and Q933a. They represent the
ANSI Annex D, Cisco, and ITU Q933-A (Annex A) LMI types, respectively. HDLC is a WAN protocol same
as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.

QUESTION 11

RouterA is unable to reach RouterB. Both routers are running IOS version 12.0. After reviewing the
command output and graphic, what is the most likely cause of the problem?

A.incorrect bandwidth configuration
B.incorrect LMI configuration
C.incorrect map statement
D.incorrect IP address

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
we have to say this is an unclear question and it is wrong. The “frame-relay map ip” First
statement is correct thus none of the four answers above is correct. But we guess there is a typo in the
output. Maybe the “ip address 172.16.100.2 255.255.0.0 command should be “ip address 172.16.100.1 255.255.0.0.

QUESTION 12

Refer to the exhibit. What is the meaning of the term dynamic as displayed in the output of the show framerelay map command shown?

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 172.16.3.1 from a DHCP server.
D.The DLCI 100 will be dynamically changed as required to adapt to changes in the Frame Relay cloud.
E.The mapping between DLCI 100 and the end station IP address 172.16.3.1 was learned through Inverse ARP.

Correct Answer: E
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Inverse Address Resolution Protocol (Inverse ARP) was developed to provide a mechanism for dynamic
DLCI to Layer 3 address maps. Inverse ARP works much the same way Address Resolution Protocol (ARP)
works on a LAN. However, with ARP, the device knows the Layer 3 IP address and needs to know the
remote data link MAC address. With Inverse ARP, the router knows the Layer 2 address which is the DLCI,
but needs to know the remote Layer 3 IP address. 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-toLayer 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.

QUESTION 13

A network administrator needs to configure a serial link between the main office and a remote location. The
router at the remote office is a non-Cisco router. How should the network administrator configure the serial
interface of the main office router to make the connection?

A.Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# no shut
B.Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation ppp
Main(config-if)# no shut
C.Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation frame-relay
Main(config-if)# authentication chap
Main(config-if)# no shut
D.Main(config)# interface serial 0/0
Main(config-if)#ip address 172.16.1.1 255.255.255.252
Main(config-if)#encapsulation ietf
Main(config-if)# no shut

Correct Answer: B
Section: (none)
Explanation

Explanation/Reference:
Explanation:
With serial point to point links there are two options for the encapsulation. The default, HDLC, is Cisco
proprietary and works only with other Cisco routers. The other option is PPP which is standards based and
supported by all vendors.

QUESTION 14

What are three reasons that an organization with multiple branch offices and roaming users might
implement a Cisco VPN solution instead of point-to-point WAN links? (Choose three.)

A.reduced cost
B.better throughput
C.broadband incompatibility
D.increased security
E.scalability
F. reduced latency

Correct Answer: ADE
Section: (none)
Explanation

Explanation/Reference:
Explanation:
IPsec offer a number of advantages over point to point WAN links, particularly when multiple locations are
involved. These include reduced cost, increased security since all traffic is encrypted, and increased
scalability as s single WAN link can be used to connect to all locations in a VPN, where as a point to point
link would need to be provisioned to each location.

QUESTION 15

Which two statistics appear in show frame-relay map output? (Choose two.)

A.the number of BECN packets that are received by the router
B.the value of the local DLCI
C.the number of FECN packets that are received by the router
D.the status of the PVC that is configured on the router
E.the IP address of the local router

Correct Answer: BD
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Sample “show frame-relay map” output:
R1#sh frame mapSerial0/0 (up): ip 10.4.4.1 dlci 401(0x191,0x6410), dynamic,broadcast,, status defined,
activeSerial0/0 (up): ip 10.4.4.3 dlci 403(0x193,0x6430), dynamic,broadcast,, status defined, activeSerial0/0
(up): ip 10.4.4.4 dlci 401(0x191,0x6410), static,CISCO, status defined, active

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