Introduction to Networks Version 6 – ITN Chapter 7 Exam

Introduction to Networks (Version 6.00) – ITN Chapter 7 Exam

QUESTION 1

What information does a router running a link-state protocol use to build and maintain its topologicaldatabase? (Choose two.)

A. hello packets
B. SAP messages sent by other routers
C. LSAs from other routers
D. beacons received on point-to-point links
E. routing tables received from other link-state routers
F. TTL packets from designated routers

Correct Answer: AC
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Neighbor discovery is the first step in getting a link state environment up and running. In keeping with the friendly neighbor terminology, a Hello protocol is used for this step. The protocol will define a Hello packet format and a procedure for exchanging the packets and processing the information the packets contain.
After the adjacencies are established, the routers may begin sending out LSAs. As the term flooding implies, the advertisements are sent to every neighbor. In turn, each received LSA is copied and forwarded to every neighbor except the one that sent the LSA.

QUESTION 2

Which statements describe the routing protocol OSPF? (Choose three.)

A. It supports VLSM.
B. It is used to route between autonomous systems.
C. It confines network instability to one area of the network.
D. It increases routing overhead on the network.
E. It allows extensive control of routing updates.
F. It is simpler to configure than RIP v2.

Correct Answer: ACE
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The OSPF protocol is based on link-state technology, which is a departure from the Bellman-Ford vector based algorithms used in traditional Internet routing protocols such as RIP. OSPF has introduced new concepts such as authentication of routing updates, Variable Length Subnet Masks (VLSM), route summarization, and so forth.
OSPF uses flooding to exchange link-state updates between routers. Any change in routing information is flooded to all routers in the network. Areas are introduced to put a boundary on the explosion of link-state updates. Flooding and calculation of the Dijkstra algorithm on a router is limited to changes within an area.

QUESTION 3

Refer to the exhibit. A network administrator configures a new router and enters the copy startup- config
running-config command on the router. The network administrator powers down the router and sets it up at a remote location. When the router starts, it enters the system configuration dialog as shown. What is the cause of the problem?

A.The network administrator failed to save the configuration.
B.The configuration register is set to 0x2100.
C.The boot system flash command is missing from the configuration.
D.The configuration register is set to 0x2102.
E.The router is configured with the boot system startup command.

Correct Answer: A
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The “System Configuration Dialog” appears only when no startup configuration file is found. The network
administrator has made a mistake because the command “copy startup-config running- config” will copy the
startup config (which is empty) over the running config (which is configured by the administrator). So
everything configured was deleted. Note: We can tell the router to ignore the start-up configuration on the
next reload by setting the register to 0?142. This will make the “System Configuration Dialog” appear at the
next reload.

QUESTION 4

Refer to the exhibit. Which WAN protocol is being used?

A.ATM
B.HDLC
C.Frame Relay
D.PPP

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
This question is to examine the show int command. According to the information provided in the exhibit, we can know that the
data link protocol used in this network is the Frame Relay protocol.
“LMI enq sent…”

QUESTION 5

What is the default administrative distance of OSPF?

A.90
B.100
C.110
D.120

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Administrative distance is the feature that routers use in order to select the best path when there are two or
more different routes to the same destination from two different routing protocols. Administrative distance
defines the reliability of a routing protocol. Each routing protocol is prioritized in order of most to least
reliable (believable) with the help of an administrative distance value.
Default Distance Value Table
This table lists the administrative distance default values of the protocols that Cisco supports:
Route Source
Default Distance Values
Connected interface
Static route
Enhanced Interior Gateway Routing Protocol (EIGRP) summary route External Border Gateway Protocol
(BGP)
Internal EIGRP
IGRP
OSPF
Intermediate System-to-Intermediate System (IS-IS)
Routing Information Protocol (RIP)
Exterior Gateway Protocol (EGP)
On Demand Routing (ODR)
External EIGRP
Internal BGP
Unknown*

QUESTION 6

Which characteristics are representative of a link-state routing protocol? (Choose three.)

A.provides common view of entire topology
B.exchanges routing tables with neighbors
C.calculates shortest path
D.utilizes event-triggered updates
E.utilizes frequent periodic updates

Correct Answer: ACD
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Each of routers running link-state routing protocol learns paths to all the destinations in its “area” so we can
say although it is a bit unclear.
Link-state routing protocols generate routing updates only (not the whole routing table) when a change occurs in the network topology so
Link-state routing protocol like OSPF uses Dijkstra algorithm to calculate the shortest path -> . Unlike
Distance vector routing protocol (which utilizes frequent periodic updates), link-state routing protocol utilizes
event-triggered updates (only sends update when a change occurs) ->

QUESTION 7

Refer to the exhibit. Based on the exhibited routing table, how will packets from a host within the
192.168.10.192/26 LAN be forwarded to 192.168.10.1?

A.The router will forward packets from R3 to R2 to R1.
B.The router will forward packets from R3 to R1 to R2.
C.The router will forward packets from R3 to R2 to R1 AND from R3 to R1.
D.The router will forward packets from R3 to R1.

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
From the routing table we learn that network 192.168.10.0/30 is learned via 2 equal-cost paths
(192.168.10.9 &192.168.10.5) -> traffic to this network will be load-balancing.

QUESTION 8

Refer to the exhibit. C-router is to be used as a “router-on-a-stick” to route between the VLANs. All the
interfaces have been properly configured and IP routing is operational. The hosts in the VLANs have been
configured with the appropriate default gateway. What is true about this configuration?

A.These commands need to be added to the configuration:
C-router(config)# router eigrp 123
C-router(config-router)# network 172.19.0.0
B.These commands need to be added to the configuration:
C-router(config)# router ospf 1
C-router(config-router)# network 172.19.0.0 0.0.3.255 area 0
C.These commands need to be added to the configuration:
C-router(config)# router rip
C-router(config-router)# network 172.19.0.0
D.No further routing configuration is required.

Correct Answer: D
Section: (none)
Explanation

Explanation/Reference:
Explanation:
Since all the same router (C-router) is the default gateway for all three VLANs, all traffic destined to a
different VLA will be sent to the C-router. The C-router will have knowledge of all three networks since they
will appear as directly connected in the routing table. Since the C-router already knows how to get to all
three networks, no routing protocols need to be configured.

QUESTION 9

Which command would you configure globally on a Cisco router that would allow you to view directly
connected Cisco devices?

A.enable cdp
B.cdp enable
C.cdp run
D.run cdp

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
CDP is enabled on Cisco routers by default. If you prefer not to use the CDP capability, disable it with the no
cdp run command. In order to reenable CDP, use the cdp run command in global configuration mode. The
“cdp enable” command is an interface command, not global.

QUESTION 10

Refer to the exhibit. Why is flash memory erased prior to upgrading the IOS image from the TFTP server?

A.The router cannot verify that the Cisco IOS image currently in flash is valid.
B.Flash memory on Cisco routers can contain only a single IOS image.
C.Erasing current flash content is requested during the copy dialog.
D.In order for the router to use the new image as the default, it must be the only IOS image in flash.

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
During the copy process, the router asked “Erasing flash before copying? [confirm]” and the administrator
confirmed (by pressing Enter) so the flash was deleted. Note: In this case, the flash has enough space to
copy a new IOS without deleting the current one. The current IOS is deleted just because the administrator
wants to do so. If the flash does not have enough space you will see an error message like this:
%Error copying tftp://192.168.2.167/ c1600-k8sy-mz.l23-16a.bin (Not enough space on device)

QUESTION 11

Refer to the exhibit. According to the routing table, where will the router send a packet destined for
10.1.5.65?

A.10.1.1.2
B.10.1.2.2
C.10.1.3.3
D.10.1.4.4

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The destination IP address 10.1.5.65 belongs to 10.1.5.64/28, 10.1.5.64/29 & 10.1.5.64/27 subnets but the
“longest prefix match” algorithm will choose the most specific subnet mask -> the prefix “/29 will be chosen
to route the packet. Therefore the next-hop should be 10.1.3.3 -> .

QUESTION 12

Refer to the exhibit. Which address and mask combination represents a summary of the routes learned by
EIGRP?

A.192.168.25.0 255.255.255.240
B.192.168.25.0 255.255.255.252
C.192.168.25.16 255.255.255.240
D.192.168.25.16 255.255.255.252
E.192.168.25.28 255.255.255.240
F. 192.168.25.28 255.255.255.252

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The binary version of 20 is 10100.
The binary version of 16 is 10000.
The binary version of 24 is 11000.
The binary version of 28 is 11100.
The subnet mask is /28. The mask is 255.255.255.240.
Note:
From the output above, EIGRP learned 4 routes and we need to find out the summary of them:
+ 192.168.25.16
+ 192.168.25.20
+ 192.168.25.24
+ 192.168.25.28
-> The increment should bE. 28 ?16 = 12 but 12 is not an exponentiation of 2 so we must choose 16 (24).
Therefore the subnet mask is /28 (=1111 1111.1111 1111.1111 1111.11110000) = 255.255.255.240
So the best answer should be 192.168.25.16 255.255.255.240

QUESTION 13

Refer to the exhibit. Assuming that the entire network topology is shown, what is the operational status of
the interfaces of R2 as indicated by the command output shown?

A.One interface has a problem.
B.Two interfaces have problems.
C.The interfaces are functioning correctly.
D.The operational status of the interfaces cannot be determined from the output shown.

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The output shown shows normal operational status of the router’s interfaces. Serial0/0 is down
because it has been disabled using the “shutdown” command.

QUESTION 14

Which two locations can be configured as a source for the IOS image in the boot system command?
(Choose two.)

A.RAM
B.NVRAM
C.flash memory
D.HTTP server
E.TFTP server
F. Telnet server

Correct Answer: CE
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The following locations can be configured as a source for the IOS image:
1. + Flash (the default location)
2. + TFTP server
3. + ROM (used if no other source is found)

QUESTION 15

Refer to the exhibit. Given the output for this command, if the router ID has not been manually set, what
router ID will OSPF use for this router?

A.10.1.1.2
B.10.154.154.1
C.172.16.5.1
D.192.168.5.3

Correct Answer: C
Section: (none)
Explanation

Explanation/Reference:
Explanation:
The highest IP address of all loopback interfaces will be chosen -> Loopback 0 will be chosen as the router ID.

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