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CCNA 2 - Module 8: The Routing Table - A Closer Look


Exam Answers v3.x and v4.0


Options with "*" are correct answer

1 Which layer protocols provide reliability for IP when needed?
ICMP and ping
* upper layer protocols
lower layer protocols
Internet layer protocols
network access layer protocols

2 How does ICMP improve data transfer reliability in IP networks?
Each router in the path reads ICMP packets and uses the information to update routing tables.
ICMP can correct many network problems as they occur.
* ICMP error messages are returned to the sending device when a packet is dropped by a router.
ICMP packets report the intermediary devices that a packet passed through before failure occurred.

3 When a datagram is processed by a router on the path from source to destination, what happens to the value in the TTL field?
It is increased by one.
* It is decreased by one.
It stays the same.
It is reset to 0.

4 If workstation 4 sends a message to workstation 2 and it is not delivered, which protocol will report this failure?

Internet Protocol
User Datagram Protocol
Transmission Control Protocol
* Internet Control Message Protocol

5 What does a router do if it is unable to deliver a packet to its destination? (Choose two.)
The router sends the original packet back to the source.
The router keeps the packet in its buffer until the next routing table update.
* The router sends an ICMP "Destination Unreachable" message back to the source. *
The router sends out a broadcast message in search of the destination.
* The router discards the original packet.

6 Which two statements are true regarding ICMP? (Choose two.)

ICMP provides reliability for the TCP/IP protocol stack.
* ICMP is a component of the TCP/IP protocol stack.
* ICMP notifies the sender that data transmission errors have occurred.
ICMP is connection-oriented.
ICMP messages are propagated to all intermediate devices.

7 Which confirms the availability of a destination? (Choose two.)

The source issues an echo reply after receiving an echo request from the destination.
* The destination returns an exact copy of the data sent by the source.
* The source sends an echo request and receives an echo reply.
The source sends the data to the destination without receiving a reply.
The destination sends an echo request and receives an echo reply.

8 Workstation 1 sent a data packet to Workstation 4. It never arrived because Fa0/0 interface went down on Router C. How will the devices handle this failure?
Workstation 4 will send an error message to Router C and Workstation 1 that it did not receive the packet.
* Router C will use ICMP to send a message back to Workstation 1 indicating that the packet could not be delivered.
Router C discards the packet without providing notification to any device.
Router C uses ICMP to correct the failure and transmits the data to Workstation 4.
Workstation 1 will use ICMP to correct the problem and then notify Router C to continue the transmission.

9 Which three conditions must be met in order for host to host communication over an internetwork to occur on IP networks? (Choose three.)
The routing protocols configured on the source and destination networks must be the same.
* A default gateway must be properly configured on the hosts and local networks.
* Intermediary devices, such as routers, must be present on the network and have knowledge of how to reach the destination network.
The source and destination host subnet masks must match.
* The IP addresses of the hosts must be in the same network or subnet as their respective gateway devices.

10 Which devices along a data transmission path are notified by ICMP when delivery failures occur?
* source devices only
destination devices only
intermediary devices
source and destination devices
source, intermediary, and destination devices

11 Which condition could cause a fragmentation needed ICMP destination unreachable message to be sent?
A low bandwidth WAN link has become congested with IP traffic.
* A packet is forwarded from a Token Ring network to an Ethernet network.
A network is not reachable because of faulty routing information.
The address specified by the sending host is nonexistent.

12 Which type of message is generated by a host when the ping command is entered?
* ICMP echo request
ICMP echo reply
UDP echo request
UDP error message

13 Which of the following start the test of destination reachability?
* echo request issued by source
echo reply issued by source
echo request issued by destination
echo reply issued by destination

14 Which ICMP message is sent to a source host when the hop count to the destination is greater than the TTL value of a packet?
echo reply
timestamp reply
destination unreachable
* time exceeded
source quench



Options with highlight colours are correct answer

1. Refer to the exhibit. What can be determined from this output?
• The router will have to perform recursive lookups to forward a packet destined for
• The parent route for these networks was removed from the routing table.
• A route to would be classified as a supernet route for the routes listed in the routing table.
• All of the routes listed are network routes.

2. Refer to the exhibit. A packet destined for host is processed by the JAX router. After finding the static route in the routing table that matches the destination network for this packet, what does the router do next?
• searches for a default route to forward the packet
• drops the packet since the static route does not have an exit interface
• performs a recursive lookup to find the exit interface used to forward the packet
• sends a request to neighboring routers for the location of the network

3. Refer to the exhibit. What parent network will automatically be included in the routing table when the three subnets are configured on Router1?


4. The following entry is displayed in the routing table: R [120/2] via, 00:00:26, Serial0/0/1 What type of route is this?
• a level 1 parent route
• a level 1 supernet route
• a level 1 ultimate network route
• a level 2 child route
• a level 2 ultimate child route

5. Refer to the exhibit. Router1 is running IOS version 12.2. What will the network administrator need to do so that packets for unknown child routes of will not be dropped?
• issue the ip default-network command
• use a classful routing protocol such as RIPv1
• enable either OSPF or ISIS as the routing protocol
• issue the ip classless command
• do nothing, ip classless is on by default

6. Refer to the exhibit. Router B receives a packet with a destination address of What will router B do?

• drop the packet
• forward the packet via the route to
• forward the packet via the route to
• use the default route

7. Refer to the exhibit. How many routes in this output qualify for use as ultimate routes?
• 3
• 4
• 5
• 6
• 7
• 8

8. Refer to the exhibit. With the ip classless command issued, what will router R2 do with a packet destined for host

• drop the packet
• send packet out Serial 0/0/1
• send packet to network
• send packet out FastEthernet 0/0

9. Refer to the exhibit. Which statement correctly describes this network?

• EIGRP is being used
• There is at least one parent and one child route
•,, and networks are child routes
• Traffic going to will be directed to s 0/0/1

10. Refer to the exhibit. Router1 has been issued the ip classless command. What happens to packets destined to host

• they are dropped
• sent to default gateway
• forward out interface Serial0/0/1
• forward out interface FastEthernet 0/0

11. Refer to the exhibit. The network administrator has discovered that packets destined for servers on the network are being dropped by Router2. What command should the administrator issue to ensure that these packets are sent out the gateway of last resort, Serial 0/0/1?

• ip classless
• A router has the following entries in its routing table:
• S [1/0] via
• O [110/2175] via, 00:02:15, FastEthernet0/1
• D [90/22455] via, 00:12:15, Serial0/0/0
• R [120/2] via, 00:00:15, Serial0/0/1

12. The router receives a packet that is destined for a host with the address Which route would this router use to forward the packet?

• router use to forward the packet
• the static route
• the OSPF route
• the EIGRP route
• the RIP route

13.What determines if the router implements a classless route lookup process?
• Child routes are present in the routing table.
• A classless routing protocol has been configured on the router.
• The command ip classless is enabled on the router.
• Multiple routes with different masks to the same destination are in the routing table.
• Routing table entries have a next-hop IP address and an exit interface for each child route.

14. What occurs when no ip classless is implemented on the router?
• The router will only support classful IP addressing.
• The router will only support classful routing protocols.
• The router will use a default route, if present, when a matching route is not found in the routing table.
• The router will assume it has knowledge of all subnets in the network and will not search beyond child
• routes for a better match.

15. Refer to the exhibit. The graphic contains partial contents of the routing table on router E. Router E is running version 12.3 of the IOS and is configured for default routing behavior. Router E receives a packet to forward. Which route in the routing table will be searched first and why?
• because it is the first ultimate route
• because it is the lowest network number
• because it is the first level 1 route
• because it has the shortest mask

16. A network is converged and the routing tables are complete. When a packet needs to be forwarded, what is the first criterion used to determine the best path in the routing table?

• the route with the smallest AD
• the route with the longest address and mask match to the destination
• the route with the highest bandwidth
• the route with the best combination of AD and lowest cost

17. Refer to the exhibit. What subnet mask will Router1 apply to child routes of the network?


18. Refer to the exhibit. What protocol was used to distribute the routing information for the network

• RIPv1
• RIPv2

19. A route to a destination network is learned from multiple routing protocols. What is used by a Cisco router to select the preferred route to the destination that will be installed in the routing table?

• metric
• route prefix
• update timer
• administrative distance

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