CCNA Exploration 4.0: Routing Protocols and Concepts - Chapter 9 Exam Answers

1. On a router running EIGRP, what database would maintain a list of feasible successors?

routing table
neighbor table
*topology table
adjacency table

2. Refer to the exhibit. This is the debug output from 2 directly connected EIGRP routers. They are not forming an adjacency. What is the cause?

*one router is a non-cisco router
they have different autonomous-system numbers
they are using difference sequence numbers
they are sending incorrect hello types

3. Refer to the exhibit. Which command will advertise the 192.168.1.64/30 network but not the 192.168.1.32 network on router A?

network 192.168.1.0
network 192.168.1.0 255.255.255.0
network 192.168.1.64 0.0.0.3
*network 192.168.1.64 0.0.0.7
network 192.168.1.64 0.0.0.255

4. What two actions will the EIGRP DUAL FSM take if a link to a network goes down? (Choose two.)

*put the route into passive mode
query neighbors for a new route
search routing table for a feasible successor
*run the SPF algorithm to find a new successor
search topology table for a feasible successor

5. Refer to the exhibit. What is indicated by the P at the beginning of the topology entry?

the route is in a stable state
the route is a preferred route
*DUAL is searching for a better route to this destination
the exit interface is in passive mode and EIGRP advertisements are blocked

6. In which of the following tables does the EIGRP DUAL algorithm store the primary route to a destination? (Choose two.)

routing
topology
*neighbor
path
*shortest path

7. What information is maintained in the EIGRP topology database for a destination route? (Choose three.)

the routing protocol
the feasible distance of the route
*the highest cost of the route
*the SRTT value for the route
the route cost as advertised by the neighboring router
*the physical address of the gateway interface

8. Which of the following statements describes the bounded updates used by EIGRP?

Bounded updates are sent to all routers within an autonomous system.
Partial updates are sent only to routers that need the information.
*The updates are sent to all routers in the routing table.
Updates are bounded by the routers in the topology table.

9. Which of the following types of routes will be denoted by EX in EIGRP routing table entries? (Choose two.)

routes learned from other routing protocols
routes learned from any non-adjacent EIGRP routers
*any route with a hop count metric higher than 224
EIGRP routes that originate in different autonomous systems
*all passive routes in the routing table

10. Host 192.168.1.66 in the network illustrated is unable to ping host 192.168.1.130. How must EIGRP be configured to enable connectivity between the two hosts? (Choose two.)

*R1(config-router)# network 192.168.1.128
R1(config-router)# auto-summary
R1(config-router)# no auto-summary
R2(config-router)# no auto-summary
R2(config-router)# auto-summary
*R2(config-router)# network 192.168.1.64

11. Which two statements describe characteristics of EIGRP? (Choose two.)

EIGRP is a distance vector routing protocol.
EIGRP supports classless routing and VLSM.
*EIGRP is classified as a link-state routing protocol.
EIGRP uses TCP for reliable delivery of EIGRP update packets.
*With EIGRP, loop-free paths are achieved through the use of hold-down timers.
EIGRP sends a periodic update every 30 minutes.

12. Refer to the exhibit. Based on the output of show ip eigrp neighbors, what are two possible problems with adjacencies between Router1 and Router2? (Choose two.)

The routers are configured with different EIGRP process IDs.
*Automatic summarization was disabled.
The hello timer for R1 was altered.
The serial interfaces for both routers are in different networks.
*No feasible successors were found.

13. Refer to the exhibit. In the topology table, what do the numbers 3011840 and 3128695 represent?

the route metric that is applied to those EIGRP routes for this router
the trustworthiness of the routing information source
*the composite of the hop count and bandwidth to that destination network
the total metric for that network as advertised by the EIGRP neighbor

14. Refer to the exhibit. EIGRP is the only routing protocol enabled on this network. No static routes are configured on this router. What can be concluded about network 198.18.1.0/24 from the exhibited output?

A route to network 198.18.1.0/24 is not listed in the routing table.
Packets that are destined for 198.18.1.0/24 will be forwarded to 198.18.10.6.
*EIGRP will perform equal cost load balancing across two paths when forwarding packets to 198.18.1.0/24.
The router with interface 172.16.3.2 is a successor for network 198.18.1.0/24.

15. Refer to the exhibit. All interfaces have been configured with the bandwidths that are shown in the exhibit. Assuming that all routers are using a default configuration of EIGRP as their routing protocol, what path will packets take from the 172.16.1.0/16 network to the 192.168.200.0/24 network?

A,B,E
A,C,E
*A,D,E
Packets will load balance across the A,B,E and A,C,E paths.
Packets will load balance across the A,B,E and A,D,E paths.
Packets will load balance across the A,C,E and A,D,E paths.

16. By default, which two metrics are used by EIGRP to determine the best path between networks?

*MTU
load
delay
bandwidth
*reliability

17. Which term defines a collection of networks under the administrative control of a single entity that presents a common routing policy to the Internet?

autonomous system
contiguous networks
process ID
*BGP

18. Refer to the exhibit. The company is using EIGRP with an autonomous system number of 10. Pings between hosts on networks that are connected to router A and those that are connected to router B are successful. However, users on the 192.168.3.0 network are unable to reach users on the 192.168.1.32 network. What is the most likely cause of this problem?

IP classless is enabled and is causing the packet to drop.
*The command network 192.168.1.32 was not issued on router C.
The routers are not configured in the same EIGRP routing domain.
Automatic summarization of the networks is causing the subnetted routes to be dropped.

19. In the command router eigrp 20, what is the purpose of the number 20?

specifies the administrative distance for all EIGRP routes
identifies the autonomous system number this EIGRP process will advertise
*determines what metric is added to all advertised routes
indicates the number of addresses in the EIGRP routing domain

20. The show ip eigrp topology command output on a router displays a successor route and a feasible successor route to network 192.168.1.0/24. In order to reduce processor utilization, what does EIGRP do when the primary route to this network fails?

The router sends query packets to all EIGRP neighbors for a better route to network 192.168
The DUAL FSM immediately recomputes the algorithm to calculate the next backup route.
*Packets that are destined for network 192.168.1.0/24 are sent out the default gateway instead.
The backup route to network 192.168.1.0/24 is installed in the routing table.

21. What administrative distance would a router assign to a default route in EIGRP that is learned from a source external to the autonomous system?

1
5
70
*90
170
190

22. Refer to the exhibit. Network 192.168.0.0/28 goes down. What type of packet does Router2 immediately send to Router1 and Router3?

a query for network 192.168.0.0/28
an acknowledgment packet to 224.0.0.9
an update packet that is sent to 255.255.255.255
a packet that contains the new routing table for R2
unicast update packets to 192.168.1.1 and 192.168.2.1

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CCNA Exploration 4.0: Routing Protocols and Concepts - Chapter 8 Exam Answers

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 192.168.2.213/24.
The parent route for these networks was removed from the routing table.
A route to 192.168.0.0/25 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 128.107.0.5/16 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 128.107.0.0 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?

* 172.16.0.0/16
172.16.0.0/24
172.16.0.0/30
172.16.1.0/16
172.16.1.0/24

4. The following entry is displayed in the routing table:

R 192.168.8.0/24 [120/2] via 192.168.4.1, 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 172.16.0.0/24 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 10.16.1.97. What will router B do?

drop the packet
forward the packet via the route to 10.16.1.0
forward the packet via the route to 10.16.1.64
* use the default route

7.

Refer to the exhibit. How many routes in this output qualify for use as ultimate routes?

3
4
5
* 7
8

8.

Refer to the exhibit. With the ip classless command issued, what will router R2 do with a packet destined for host 172.16.4.234?

drop the packet
* send packet out Serial 0/0/1
send packet to network 0.0.0.0
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
192.168.2.0, 192.168.3.0, and 192.168.4.0 networks are child routes
Traffic going to 172.16.3.0 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 172.16.3.10?

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 172.16.254.0 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
no ip classless
ip default-network 0.0.0.0
ip default-gateway 172.16.254.1
ip route 0.0.0.0 0.0.0.0 Serial 0/0/1

12. A router has the following entries in its routing table:

S 192.168.0.0/24 [1/0] via 192.168.128.2
O 192.168.0.0/25 [110/2175] via 172.16.1.1, 00:02:15, FastEthernet0/1
D 192.168.0.0/25 [90/22455] via 172.16.2.2, 00:12:15, Serial0/0/0
R 192.168.0.0/26 [120/2] via 172.16.3.3, 00:00:15, Serial0/0/1

The router receives a packet that is destined for a host with the address 192.168.0.58. Which route would this 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?

172.16.1.0/25 because it is the first ultimate route
0.0.0.0/0 because it is the lowest network number
* 172.16.0.0/25 because it is the first level 1 route
172.18.0.0/15 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 172.16.0.0/24 network?

0.0.0.0
255.255.0.0
* 255.255.255.0
255.255.255.255

18.

Refer to the exhibit. What protocol was used to distribute the routing information for the network 172.16.1.4?

RIPv1
* RIPv2
EIGRP
OSPF

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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CCNA Exploration 4.0: Routing Protocols and Concepts - Chapter 6 Exam Answers

1 What two advantages does CIDR provide to a network? (Choose two.)

* reduced routing table size
dynamic address assignment
automatic route redistribution
* reduced routing update traffic
utomatic summarization at classful boundaries

2

Refer to the exhibit. The network administrator wants to create a subnet for the point-to-point connection between the two routers. Which subnetwork mask would provide enough addresses for the point-to-point link with the least number of wasted addresses?

255.255.255.192
255.255.255.224
255.255.255.240
255.255.255.248
* 255.255.255.252

3

Refer to the exhibit. A network engineer is summarizing the two groups of routes on router R1 shown in the exhibit. Which summarization will work for all the subnets?

192.168.0.0/23
192.168.0.0/22
* 192.168.0.0/21
192.168.0.0/20

4. Which of the following are contained in the routing updates of classless routing protocols? (Choose two.)

* 32-bit address
next hop router interface
* subnet mask
unicast host address
Layer 2 address

5. Which of the following problems does VLSM help to alleviate?

* the shortage of IP addresses
the difficulty of assigning static IP addresses to hosts in large enterprises
the complexity of implementing advanced routing protocols such as OSPF and EIGRP
the shortage of network administrators qualified in the use of RIP v1 and IGRP

6. What does VLSM allow a network administrator to do?

utilize one subnet mask throughout an autonomous system
* utilize multiple subnet masks in the same IP address space
utilize IGRP as the routing protocol in an entire autonomous system
utilize multiple routing protocols within an autonomous system

7.

Refer to the exhibit. What subnet mask will be applied if Router A sends a RIPv1 update for the network 172.16.1.0 to Router B?

none
8
16
* 24

8

Refer to the exhibit. The network administrator wants to minimize the number of entries in Router1’s routing table. What should the administrator implement on the network?

VLSM
* CIDR
private IP addresses
classful routing

9. A router has a summary route to network 192.168.32.0/20 installed in its routing table. What range of networks are summarized by this route?

192.168.0.0 – 192.168.32.0/24
192.168.0.0 – 192.168.47.0/24
* 192.168.32.0 – 192.168.47.0/24
192.168.32.0 – 192.168.48.0/24
192.168.32.0 – 192.168.63.0/24

10. A network administrator is tasked with dividing up a class C network among the QA, Sales, and Administration departments. The QA department is made up of 10 people, the Sales is made up of 28 people, and the Administration has 6. Which two subnets masks adequately address the QA and Sales departments? (Choose two.)

255.255.255.252 for QA
* 255.255.255.224 for Sales
* 255.255.255.240 for QA
255.255.255.248 for QA
255.255.255.0 for Sales

11.

In the network shown in the graphic, three bits were borrowed from the host portion of a Class C address. How many valid host addresses will be unused on the three point-to-point links combined if VLSM is not used?

3
4
12
36
* 84
180

12. A Class C address has been assigned for use in the network shown in the graphic. Using VLSM, which bit mask should be used to provide for the number of host addresses required on Router A, while wasting the fewest addresses?

/31
/30
/29
/28
* /27
/26

13

An additional subnet is required for a new Ethernet link between Router1 and Router2 as shown in the diagram. Which of the following subnet addresses can be configured in this network to provide a maximum of 14 useable addresses for this link while wasting the fewest addresses?

192.1.1.16/26
192.1.1.96/28
192.1.1.160/28
192.1.1.196/27
* 192.1.1.224/28
192.1.1.240/28

14. Which three interior routing protocols support VLSM? (Choose three.)

* OSPF
RIP v1
* RIP v2
* EIGRP
BGP
STP

15.

Refer to the exhibit. The number of required host addresses for each subnet in a network is listed in the exhibit. This number includes the host address requirements for all router ports and hosts on that subnet. After all device and router port address assignments are determined, what will be the total number of unused host addresses available?

6
14
* 29
34
40
62

16

Refer to the exhibit. In the network that is shown, the router interfaces are assigned the first address in each subnet. Which IP address would be usable for a host on one of the LANs in this network?

192.168.1.5/30
192.168.2.17/28
192.168.2.63/27
* 192.168.2.130/25

17

Refer to the exhibit. Which address is a broadcast address for one of the subnets that are shown in the exhibit?

192.168.4.3/29
* 192.168.4.15/29
192.168.4.65/26
192.168.4.255/24

18

Refer to the exhibit. A network administrator needs to create two subnetworks from 10.0.0.0/8 for a router running RIPv2. The Admin subnet requires 120 hosts and the Sales subnet requires 58 hosts. The network administrator assigned 10.0.1.128/25 to the Admin subnet. The Sales subnet is given 10.0.1.192/26. What will be the result of this addressing scheme?

Because RIPv2 does not support VLSM, the subnet masks will not be allowed.
The subnets will not have enough host addresses for the given network requirements.
* The subnets overlap and will be rejected by the router.
The router will support the addressing scheme.

19

Refer to the exhibit. A network technician enters the static route in R1 needed to reach network 10.1.1.0/24. A ping from the S0/0/0 interface on R1 to host B fails. The technician begins testing the network and has the following results:

1. pings from R1 to the S0/0/0 interface on R2….successful
2. pings from R1 to the Fa0/0 interface on R2….successful
3. pings from host B to hosts on the 10.1.1.0/24 network….successful
4. pings from host B to the Fa0/0 interface on R2….successful
5. pings from R2 to host B….successful.

What is the likely cause of the failure of the ping from R1 to host B?

* The default gateway on host B is not correctly set.
There are no routes back to networks connected to R1 from R2.
There is a Layer 2 problem between R2 and host B.
Host B has a defective Ethernet card.

20. What is a supernet?

the network for a default route
* a summarization of classful addresses
a network that contains both private and public addresses
a set of discontiguous networks that are controlled by an ISP

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CCNA Exploration 4.0: Routing Protocols and Concepts - Chapter 5 Exam Answers

1

Refer to the exhibit. The network that is shown is running RIPv1. The 192.168.10.0/24 network was recently added and will only contain end users. What command or set of commands should be entered on Router1 to prevent RIPv1 updates from being sent to the end user devices on the new network while still allowing this new network to be advertised to other routers?

Router1(config-router)# no router rip
Router1(config-router)# network 192.168.10.0
Router1(config-router)# no network 192.168.10.0
* Router1(config-router)# passive-interface fastethernet 0/0
Router1(config-router)# passive-interface serial 0/0/0

2. The following line was displayed in the output of the show ip route command.

R 192.168.3.0/24 [120/3] via 192.168.2.2, 00:00:30, Serial0/0

What is the value of the routing metric?

* 3
12
20
30
120

3. Which of the following is considered a limitation of RIP v1?

* RIP v1 does not send subnet mask information in its updates.
RIP v1 is not widely supported by networking hardware vendors.
RIP v1 consumes excessive bandwidth by multicasting routing updates using a Class D address.
RIP v1 requires enhanced router processors and extra RAM to function effectively.
RIP v1 does not support load balancing across equal-cost paths.
RIP v1 authentication is complicated and time-consuming to configure.

4

Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still in the Router1 routing table. How much longer will Router1 keep the down network in its routing table before marking it as possibly down?

30 seconds
90 seconds
* 155 seconds
180 seconds
255 seconds

5

Refer to the exhibit. Router1 is running RIPv1. What command was entered into Router1 to configure the gateway of last resort?

no auto-summary
ip default-network 0.0.0.0
ip default-gateway 0.0.0.0
* ip route 0.0.0.0 0.0.0.0 S0/0/1

6. What are three characteristics of the RIPv1 routing protocol? (Choose three.)

supports the use of VLSM
* uses hop count as a metric
* considers a metric of 16 as infinity
has an administrative distance of 110 by default
includes the destination IP address and subnet mask in routing updates
calculates metrics using the Bellman Ford algorithm

7

Which of the following would be the correct command sequence to enable RIP on Router B for all connected networks?

RouterB# router rip
RouterB(router)# network 210.36.7.0
RouterB(router)# network 220.17.29.0
RouterB(router)# network 211.168.74.0

RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0
RouterB(config-router)# network 211.168.74.0
RouterB(config-router)# network 199.84.32.0

RouterB(config)# configure router rip
RouterB(config-router)# network 210.36.7.0
RouterB(config-router)# network 199.84.32.0
RouterB(config-router)# network 211.168.74.0

RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0
RouterB(config-router)# network 210.36.7.0
RouterB(config-router)# network 211.168.74.0

* RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0
RouterB(config-router)# network 210.36.7.0
RouterB(config-router)# network 220.17.29.0

8. What is the default update period in seconds for the RIP routing protocol?

10
12
15
20
* 30
60

9

Refer to the exhibit. What can be concluded from the routing table output of router B?

A static default route has been configured on B.
* The default-information originate command has been entered on A.
All traffic that is destined for 192.168.1.1 will be sent to address 0.0.0.0.
Hosts on the 10.16.1.0/27 network have 192.168.1.1 configured as the default gateway address.

10

Refer to the exhibit. A network consists of multiple routers. What can be verified when the show ip protocols command is issued on one of the routers in the network?

whether all routes in the network have been properly added to the routing table
* routing protocol configuration in use for IP on this router
operational status of routing protocols in use on all routers in the network
routing metric of each network that is listed in the routing table

11

Refer to the exhibit. All routers are configured with valid interface addresses in the indicated networks and are running RIPv1. The network is converged. Which routes are present in the routing tables?

All routers have all routes in their routing table.
All routers have all /30 routes, but do not have /24 routes in their routing table.
* All routers have all /30 routes. Routers A and E also have some of the /24 routes in their routing table.
All routers have all /30 routes. Routers B and D also have some of the /24 routes in their routing table.
Routers A and E have all routes. Routers B and D have only /30 routes in their routing table.
Routers A and E have only /24 routes. Routers B and D have only /30 routes in their routing table.

12. Which two statements are true regarding the characteristics of RIPv1? (Choose two).

* It is a distance vector routing protocol.
It advertises the address and subnet mask for routes in routing updates.
The data portion of a RIP message is encapsulated into a TCP segment.
* The data portion of a RIP message is encapsulated into a UDP segment.
It broadcasts updates every 15 seconds.
It allows a maximum of 15 routers in the routing domain.

13. Which command or set of commands will stop the RIP routing process?

RouterB(config)# router rip
RouterB(config-router)# shutdown
RouterB(config)# router rip
RouterB(config-router)# network no 192.168.2.0
* RouterB(config)# no router rip
* RouterB(config)# router no rip

14

Refer to the exhibit. All routers in the exhibit are running RIP v1. The network administrator issues the show ip route command on router A. What routes would appear in the routing table output if the network is converged? (Choose two).

* R 192.168.2.0/24 [120/1]
C 192.168.2.0/24 [120/1]
R 10.10.3.0/24 [120/0]
C 10.10.3.0/24 [120/1]
* R 10.10.1.0/24 [120/2]
R 10.10.1.0/24 [120/3]

15. Which command will display RIP activity as it occurs on a router?
* debug ip rip
show ip route
show ip interface
show ip protocols
debug ip rip config
show ip rip database

16

Refer to the output from the show ip route command. What can be concluded from the output of this router command?

A preferred route to the destination has not been set.
* There are two equal cost paths to network 1.0.0.0.
Both interfaces are being used equally to route traffic.
A variance must be set to load-balance across multiple paths.

17.

Refer to the exhibit. Router1 and Router2 are running the RIPv1 protocol. The network administrator configures the command network 10.1.0.0 on Router1. What network will Router1 advertise to Router2?

10.1.0.0/16
10.1.0.0/8
10.0.0.0/16
* 10.0.0.0/8

18.

Refer to the exhibit. Pings between the serial interfaces of the routers are successful. Hosts on each LAN can ping the Fa0/0 interface of the router to which they are directly connected through the switch. However, pings between hosts on the 10.1.1.0/24 and 10.1.2.0/24 networks are unsuccessful. What is a likely cause of this problem?

The Fa0/0 interface on R1 is configured as a passive interface.
The Fa0/0 interfaces on each router is shutdown.
* RIP is configured incorrectly on R1.
Automatic summarization is preventing the routing updates from being forwarded.
The network has not converged and R2 must wait 12 more seconds before receiving a full routing table update from R1.

19. What will happen if an interface IP address is entered for the address portion of the network command in a RIPv1 configuration instead of a network address?

The router will reject the command.
A route to the host address will be added to outgoing RIP updates.
A route to the host address will be added to the routing table.
* All interfaces in the same classful network as the configured address will be included in the RIPv1 routing process.

20.

Refer to the exhibit. All routers that are shown are running the RIP routing protocol. All unknown IP traffic must be forwarded to the ISP. What router or set of routers are recommended to have both a default route and the default-information originate command issued to implement this forwarding policy?

only Router1
* only the gateway router
all routers in the network
only the routers with LANs needing Internet access

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CCNA Exploration 4.0: Routing Protocols and Concepts - Chapter 4 Exam Answers

1. Which event will cause a triggered update?

an update routing timer expires
a corrupt update message is received
* a route is installed in the routing table
the network is converged

2. Three routers running a distance-vector routing protocol lost all power, including the battery backups. When the routers reload, what will happen?

They will share all routes saved in NVRAM prior to the power loss with their directly connected neighbors.
They will multicast hello packets to all other routers in the network to establish neighbor adjacencies.
* They will send updates that include only directly connected routes to their directly connected neighbors.
They will broadcast their full routing table to all routers in the network.

3. What does the RIP holddown timer do?

ensures an invalid route has a metric of 15
prevents a router from sending any updates after it has introduced a routing loop into the network
ensures every new route is valid before sending an update
* instructs routers to ignore updates, for a specified time or event, about possible inaccessible routes

4. Which two statements are true regarding the function of the RIPv1 routing updates? (Choose two).

updates are broadcast only when there are changes to the topology
* updates are broadcast at regular intervals
broadcast are sent to 0.0.0.0
* broadcasts are sent to 255.255.255.255
updates contain the entire network topology
only changes are included in the updates

5. Which of the following statements are correct about RIP?

uses a broadcast to update all other routers in the network every 60 seconds
uses a multicast address to update other routers every 90 seconds
* will send out an update if there is a failure of a link
updates only contain information about routes that have changed since last update

6. Which two statements describe EIGRP? (Choose two.)

EIGRP can be used with Cisco and non-Cisco routers.
* EIGRP sends triggered updates whenever there is a change in topology that influences the routing information.
EIGRP has an infinite metric of 16.
* EIGRP sends a partial routing table update, which includes just routes that have been changed.
EIGRP broadcasts its updates to all routers in the network.
EIGRP broadcasts its updates to all routers in the network.

7. Which statement is true regarding cisco’s RIP_JITTER variable?

It prevents the synchronization of routing updates by buffering the updates as they leave the router interfaces.
* It prevents the synchronization of routing updates by subtracting a random length of time ranging from 0% to 15% of the specified interval time from the next routing update interval.
It prevents the synchronization of routing updates by causing the router to skip every other scheduled update time.
It prevents the synchronization of routing updates by forcing the router to listen when its time for other updates on the lines before sending its update.

8. What actions will occur after RouterA loses connectivity to network 114.125.16.0? (Choose two.)

* RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterA.
During the next update interval, RouterB will send a RIP update out both ports that includes the inaccessible network.
During the next update interval, RouterC will send an update to RouterB stating that network 114.125.16.0 is accessible in 2 hops.
* Router C will learn of the loss of connectivity to network 114.125.16.0 from RouterB.
RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterC.

9. Which of the following methods does split horizon use to reduce incorrect routing information?

Routing updates are split in half to reduce the update time.
* Information learned from one source is not distributed back to that source.
New route information must be learned from multiple sources to be accepted.
The time between updates is split in half to speed convergence.
New route information is suppressed until the system has converged.

10.

The graphic shows a network that is configured to use RIP routing protocol. Router2 detects that the link to Router1 has gone down. It then advertises the network for this link with a hop count metric of 16. Which routing loop prevention mechanism is in effect?

split horizon
error condition
hold-down timer
* route poisoning
count to infinity

11. What is the purpose of the TTL field in the IP header?

used to mark routes as unreachable in updates sent to other routers
prevents regular update messages from reinstating a route that may have gone bad
prevents a router from advertising a network through the interface from which the update came
* limits the time or hops that a packet can traverse through the network before it should be discarded
defines a maximum metric value for each distance vector routing protocol by setting a maximum hop count

12. Which of the following can exist in a distance vector network that has not converged? (Choose three.)

* routing loops
* inconsistent traffic forwarding
no traffic forwarding until system converges
* inconsistent routing table entries
routing table updates sent to wrong destinations

13.

Refer to the exhibit. The routers in this network are running RIP. Router A has not received an update from Router B in over three minutes. How will Router A respond?

The Holddown timer will wait to remove the route from the table for 60 seconds.
* The Invalid timer will mark the route as unusable if an update has not been received in 180 seconds.
The Update timer will request an update for routes that were learned from Router B.
The Hello timer will expire after 10 seconds and the route will be flushed out of the routing table.

14. A network administrator is evaluating RIP versus EIGRP for a new network. The network will be sensitive to congestion and must respond quickly to topology changes. What are two good reasons to choose EIGRP instead of RIP in this case? (Choose two.)

EIGRP uses periodic updates.
* EIGRP only updates affected neighbors.
EIGRP uses broadcast updates.
* EIGRP updates are partial.
EIGRP uses the efficient Bellman-Ford algorithm.

15.

Refer to the exhibit. What path will packets from the 192.168.1.0/24 network travel to reach the 10.0.0.0/8 network if RIP is the active routing protocol?

The path will be router A -> router B -> router C -> router E.
* The path will be router A -> router D -> router E.
Router A will load balance between the router A -> router D -> router E and router A -> router B -> router C -> router E paths.
Packets will alternate paths depending on the order they arrive at router A.

16. Which three routing protocols are distance vector routing protocols? (Choose three).

* RIPv1
* EIGRP
OSPF
IS-IS
* RIPv2

17. What is a routing loop?

a packet bouncing back and forth between two loopback interfaces on a router
a condition where a return path from a destination is different from the outbound path forming a “loop”
* a condition where a packet is constantly transmitted within a series of routers without ever reaching its intended destination
the distribution of routes from one routing protocol into another

18. Which two conditions are most likely to cause a routing loop? (Choose two.)

random jitter
implementation of classful addressing
* inconsistent routing tables
* incorrectly configured static routes
a network converging too quickly

19. What metric does the RIP routing protocol consider to be infinity?

0
15
* 16
224
255

20. What does a router running RIP do first with a new route that is received from an advertisement?

places it immediately in the routing table
* adjusts the metric for the new route to show the added distance for the route
advertises this route out all other interfaces except the one that it came in on
sends a ping packet to verify that the path is a feasible route

21.

Refer to the exhibit. If all routers are using RIP, how many rounds of updates will occur before all routers know all networks?

1
2
* 3
4
5
6

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CCNA Exploration 4.0: Routing Protocols and Concepts - Chapter 3 Exam Answers

1. Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.)

* Administrative distance refers to the trustworthiness of a particular route.
A router first installs routes with higher administrative distances.
The value of the administrative distance can not be altered by the network administrator.
* Routes with the smallest metric to a destination indicate the best path.
The metric is always determined based on hop count.
The metric varies depending which Layer 3 protocol is being routed, such as IP or IPX.

2.

Refer to the exhibit. Which statement correctly describes how R1 will determine the best path to R2?

R1 will install a RIP route using network A in its routing table because the administrative distance of RIP is higher than EIGRP.
R1 will install a RIP route using network A in its routing table because the path cost from RIP is lower than EIGRP.
* R1 will install an EIGRP route using network B in its routing table because the administrative distance of EIGRP is lower than RIP.
R1 will install an EIGRP route using network B in its routing table because the path cost from EIGRP is lower than RIP.
R1 will install an EIGRP route and a RIP route in its routing table and load balance between them.

3. Which two statements are true regarding classless routing protocols? (Choose two.)

* sends subnet mask information in routing updates
sends complete routing table update to all neighbors
is supported by RIP version 1
* allows for use of both 192.168.1.0/30 and 192.168.1.16/28 subnets in the same topology
reduces the amount of address space available in an organization

4. Which command would the network administrator issue to determine if load balancing is in effect on a router?

show ip protocols
* show ip route
show ip interface brief
show ip interface

5. Which statement is true regarding routing protocols?

RIP uses hop count and bandwidth as the metric for path selection and sendsupdates periodically.
OSPF is a Cisco proprietary protocol that sends updates triggered by topology changes.
* EIGRP uses DUAL to calculate the shortest path and can be configured to do unequal cost load balancing.
BGP is a path vector interior routing protocol.

6. Which two conditions would create a setting where the use of a distance-vector routing protocol would be efficient? (Choose two.)

the network requires a special hierarchical design
fast convergence of the network is crucial
* the network is using a hub and spoke topology
* the network is using a flat design
there are more than 15 hops between the most distant routers

7. What is the purpose of a routing protocol?

It is used to build and maintain ARP tables.
It provides a method for segmenting and reassembling data packets.
It allows an administrator to devise an addressing scheme for the network.
* It allows a router to share information about known networks with other routers.
It provides a procedure for encoding and decoding data into bits for packet forwarding.

8. Which of the following best describes the operation of distance vector routing protocols?

They use hop count as their only metric.
They only send out updates when a new network is added.
* They send their routing tables to directly connected neighbors.
They flood the entire network with routing updates.

9. Which of the following is associated with link-state routing protocols?

low processor overhead
poison reverse
routing loops
split horizon
* shortest-path first calculations

10. Why is fast convergence desirable in networks that use dynamic routing protocols?

Routers will not allow packets to be forwarded until the network has converged.
Hosts are unable to access their gateway until the network has converged.
* Routers may make incorrect forwarding decisions until the network has converged.
Routers will not allow configuration changes to be made until the network has converged.

11. Which of the following conditions must be met in order for a network to have converged?

The routers in the network are operating with dynamic routing protocols.
The routers in the network are operating with compatible versions of IOS.
The routers in the network are operating with the same routing tables.
* The routers in the network are operating with consistent routing knowledge.

12. Which two statements are true regarding metrics? (Choose two.)

RIP uses bandwidth as a metric.
OSPF uses delay as a metric.
* EIGRP uses bandwidth as a metric.
* OSPF uses cost based on bandwidth as a metric.
RIP uses delay as a metric.
EIGRP uses hop count only as a metric.

13. Which two statements are true regarding the advantages of the use of static routes? (Choose two).

* increased security
reduced effort in configuring routes
* the administrator maintains control over routing
easier to implement in a growing network
reduces the chance of routing errors
increased router resource usage

14. The following line of code is displayed in a routing table:

R 209.165.201.0/24 [120/2] via 192.168.252.2, 00:00:16, S0/0/0

What can be concluded from this output?

A packet destined for host 192.168.252.2 will be forwarded out the interface connected to network 209.165.201.0/24.
* The value, 120, is used to determine the best path when a router has more than one routing protocol configured for the same destination network.
This route was manually configured using the ip route command.
192.168.252.2 is an interface on the router that produced this output.

15. What will be the result of the following commands?

ORL(config)# interface fastethernet 0/0
ORL(config-if)# ip address 172.16.3.1 255.255.255.0
ORL(config-if)# no shutdown

The 172.16.3.0 network will be routed by any dynamic routing protocol automatically.
* A routing table entry is made to the 172.16.3.0 network with a code of “C”.
A static route is required to route traffic to the 172.16.3.0 network.
The commands will be saved to the startup-configuration

16. An engineer creates a static route by entering the Router(config)# ip route 10.0.0.0 255.255.255.0 192.168.1.2 command. What can be concluded about this route?

* The administrative distance of this route is 1.
192.168.1.2 is the address of an interface on this router.
This route will display as a directly connected network in the routing table.
Packets with a destination IP address of 192.168.1.2 will be forwarded to the 10.0.0.0/24 network first.

17.

Refer to the exhibit. Router1 and Router2 are running EIGRP. All interfaces are operational and packets can be forwarded between all networks. What information will be found in the routing table for Router1?

Router1 will have 6 directly connected networks.
* The administrative distance of the route to network 172.16.0.0 will be 90.
The metric for routes to 172.16.0.0 will be 1.
The interface that is used to forward packets to 172.16.0.0 will always be the S0/1 interface.

18 The following line of code is present in the routing table:

O 10.16.1.0/27 [110/129] via 192.168.1.5, 00:00:05, Serial0/0/1

What does the number 129 indicate in this output?

* The cost for this link has a value of 129.
The clock rate on this serial interface is set to 129,000.
The next-hop router is 129 hops away from this router.
This route has been updated 129 times in this routing table.

19. A growing medium-sized manufacturing company recently began to have routing instability issues. The company uses static routes and has a mixture of over 30 Cisco and non-Cisco routers. The network administrator has decided to convert the network to dynamic routing. What characteristics of protocols should be considered in this selection process?

Distance vector routing protocols, such as RIP, converge more quickly than do link-state routing protocols.
EIGRP can be used on all of the routers in the company.
* OSPF can be used between the routers.
An exterior routing protocol, such as BGP, is recommended for growing companies.

20.

Refer to the exhibit. If RIP is the routing protocol, what is the value of the metric from router A to network 192.168.5.0/24?

* 3
4
56
624
724

21. A router learns two paths with equal metrics to a destination network via the RIP routing protocol. How will the router handle packets to the destination network?

The router will install the first route it learned into the routing table.
* The router will install both routes in the routing table and load balance between the two.
The router will put the first route in the routing table, and denote the second route as a backup route.
The router will pick the path with the higher bandwidth and will place it in the routing table

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