CCNA – OSPF Questions 2

Question 1

Refer to the exhibit. Which two statements are true about the loopback address that is configured on RouterB? (Choose two)

A. It ensures that data will be forwarded by RouterB.
B. It provides stability for the OSPF process on RouterB.
C. It specifies that the router ID for RouterB should be 10.0.0.1.
D. It decreases the metric for routes that are advertised from RouterB.
E. It indicates that RouterB should be elected the DR for the LAN.

Answer: B C

Explanation

A loopback interface never comes down even if the link is broken so it provides stability for the OSPF process (for example we use that loopback interface as the router-id) -> B is correct.
The router-ID is chosen in the order below:
+ The highest IP address assigned to a loopback (logical) interface.
+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.
-> The loopback interface will be chosen as the router ID of RouterB -> C is correct.

Question 2

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

Answer: A C D

Explanation

Each of routers running link-state routing protocol learns paths to all the destinations in its “area” so we can say A is correct 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 B is not correct.
Link-state routing protocol like OSPF uses Dijkstra algorithm to calculate the shortest path -> C is correct.
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) -> D is correct but E is not correct.

Question 3

The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic. There is concern that a lack of router resources is impeding internetwork performance.
As part of examining the router resources the OSPF DRs need to be known.
All the router OSPF priorities are at the default and the router IDs are shown with each router.
Which routers are likely to have been elected as DR? (Choose two)
A. Corp-1
B. Corp-2
C. Corp-3
D. Corp4
E. Branch-1
F. Branch-2

Answer: D F

Explanation

There are 2 segments on the topology above which are separated by Corp-3 router. Each segment will have a DR so we have 2 DRs.
To select which router will become DR they will compare their router-IDs. The router with highest (best) router-ID will become DR. The router-ID is chosen in the order below:
+ The highest IP address assigned to a loopback (logical) interface.
+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.
In this question, the IP addresses of loopback interfaces are not mentioned so we will consider IP addresses of all active router’s physical interfaces. Router Corp-4 (10.1.40.40) & Branch-2 (10.2.20.20) have highest “active” IP addresses so they will become DRs.

Question 4

A network associate has configured OSPF with the command:
City(config-router)# network 192.168.12.64 0.0.0.63 area 0
After completing the configuration, the associate discovers that not all the interfaces are participating in OSPF.
Which three of the interfaces shown in the exhibit will participate in OSPF according to this configuration statement? (Choose three)
A. FastEthernet0/0
B. FastEthernet0/1
C. Serial0/0
D. Serial0/1.102
E. Serial0/1.103
F. Serial0/1.104

Answer: B C D

Explanation

The “network 192.168.12.64 0.0.0.63″ equals to network 192.168.12.64/26. This network has:
+ Increment: 64 (/26= 1111 1111.1111 1111.1111 1111.1100 0000)
+ Network address: 192.168.12.64
+ Broadcast address: 192.168.12.127
Therefore all interface in the range of this network will join OSPF -> B C D are correct.

Question 5

When running OSPF, what would cause router A not to form an adjacency with router B?

A. The loopback addresses are on different subnets.
B. The values of the dead timers on the routers are different.
C. Route summarization is enabled on both routers.
D. The process identifier on router A is different than the process identifier on router

Answer: B

Explanation

To form an adjacency (become neighbor), router A & B must have the same Hello interval, Dead interval and AREA number.

Question 6

Refer to the exhibit. The network is converged. After link-state advertisements are received from Router_A, what information will Router_E contain in its routing table for the subnets 208.149.23.64 and 208.149.23.96?

A. 208.149.23.64[110/13] via 190.173.23.10, 00:00:00:07, FastEthernet0/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, FastEthernet0/0
B. 208.149.23.64[110/1] via 190.173.23.10, 00:00:00:07, Serial1/0
208.149.23.96[110/3] via 190.173.23.10, 00:00:00:16, FastEthernet0/0
C. 208.149.23.64[110/13] via 190.173.23.10, 00:00:00:07, Serial1/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, Serial1/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, FastEthernet0/0
D. 208.149.23.64[110/13] via 190.173.23.10, 00:00:00:07, Serial1/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, Serial1/0

Answer: A

Explanation

Router_E learns two subnets subnets 208.149.23.64 and 208.149.23.96 via Router_A through FastEthernet interface. The interface cost is calculated with the formula 10⁸ / Bandwidth. For FastEthernet it is 10⁸ / 100 Mbps = 10⁸ / 10,000,000,000 = 1. Therefore the cost is 12 (learned from Router_A) + 1 = 13 for both subnets -> B is not correct.
The cost through T1 link is much higher than through T3 link (T1 cost = 10⁸ / 1.544 Mbps = 64; T3 cost = 10⁸ / 45 Mbps = 2) so surely OSPF will choose the path through T3 link -> Router_E will choose the path from Router_A through FastEthernet0/0, not Serial1/0 -> C & D are not correct.
In fact, we can quickly eliminate answers B, C and D because they contain at least one subnet learned from Serial1/0 -> they are surely incorrect.

Question 7

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 RouterD?
RouterD# show ip interface brief


A. 10.1.1.2
B. 10.154.154.1
C. 172.16.5.1
D. 192.168.5.316

Answer: C

Explanation

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

Question 8

Which commands are required to properly configure a router to run OSPF and to add network 192.168.16.0/24 to OSPF area 0? (choose two)
A. Router(config)#router ospf 1
B. Router(config)#router ospf 0
C. Router(config)#router ospf area 0
D. Router(config-router)#network 192.168.16.0 0.0.0.255 area 0
E. Router(config-router)#network 192.168.16.0 0.0.0.255 0
F. Router(config-router)#network 192.168.16.0 255.255.255.0 area 0

Answer: A D

Explanation

In the router ospf
command, the ranges from 1 to 65535 so o is an invalid number -> A is correct but B is not correct. To configure OSPF, we need a wildcard in the “network” statement, not a subnet mask. We also need to assgin an area to this process -> D is correct.

Question 9

Which parameter or parameters are used to calculate OSPF cost in Cisco routers?
A. Bandwidth, Delay and MTU
B. Bandwidth
C. Bandwidth and MTU
D. Bandwidth, MTU, Reliability, Delay and Load

Answer: B

The well-known formula to calculate OSPF cost is
Cost = 10⁸ / Bandwidth
so B is the correct answer.

Question 10

Refer to the exhibit. Why are two OSPF designated routers identified on Core-Router?

Neighbor_ID	Pri	State	Dead Time	Address	Interface
208.149.23.194	1	Full/DR	00:00:33	190.172.32.10	Ethernet1
208.149.23.60	1	Full/BDR	00:00:33	190.172.32.10	Ethernet0
208.149.23.130	1	Full/DR	00:00:39	190.172.32.10	Ethernet0

A. Core-Router is connected more than one multi-access network
B. The router at 208.149.23.130 is a secondary DR in case the primary fails.
C. Two router IDs have the same OSPF priority and are therefore tied for DR election
D. The DR election is still underway and there are two contenders for the role.

Answer: A

Explanation

OSPF elects one DR per multi-access network. In the exhibit there are two DR so there must have more than one multi-access network.

Question 11

What is the default maximum number of equal-cost paths that can be placed into the routing of a Cisco OSPF router?
A. 16
B. 2
C. unlimited
D. 4

Answer: D

Explanation

The default number of equal-cost paths that can be placed into the routing of a Cisco OSPF router is 4. We can change this default value by using “maximum-paths” command:
Router(config-router)#maximum-paths 2
Note: Cisco routers support up to 6 equal-cost paths

Question 12

What is the OSPF default frequency, in seconds, at which a Cisco router sends hello packets on a multiaccess network?
A. 10
B. 40
C. 30
D. 20

Answer: A

Explanation

On broadcast multiacess and point-to-point links, the default is 10 seconds. On NBMA, the default is 30 seconds.

Question 13

What is the default administrative distance of OSPF?
A. 120
B. 100
C. 90
D. 110

Answer: D

Question 14

What information does a router running a link-state protocol use to build and maintain its topological database? (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

Answer: A C

CCNA – OSPF Questions

Question 1

Which of the following statements below best describe the process identifier that is used to run OSPF on a router? (Choose two)
A – It is an optional parameter required only if multiple OSPF processes are running on the router
B – It is locally significant
C – It is needed to identify a unique instance of an OSPF database
D – All routers in the same OSPF area must have the same process ID if they are to exchange routing information

Answer: B C

Question 2:

Why R1 can’t establish an OSPF neighbor relationship with R3 according to the following graphic? (Choose two)

A – Configure EIGRP on these routers with a lower administrative distance
B – All routers should be configured for backbone Area 1
C – R1 and R3 have been configured in different areas
D – The hello and dead interval timers are not configured the same values on R1 and R3

Answer: C D

Explanation:

A is not correct because configure EIGRP on these routers (with a lower administrative distance) will force these routers to run EIGRP, not OSPF.
B is not correct because the backbone area of OSPF is always Area 0.
C and D are correct because these entries must match on neighboring routers:
- Hello and dead intervals
– Area ID (Area 0 in this case)
– Authentication password
– Stub area flag

Question 3:

Which items are correct about the routing protocol OSPF? (Choose three)
A – Support VLSM
B – Increase routing overhead on the network
C – Confine network instability to one area of the network
D – Allow extensive control of routing updates

Answer: A C D

Explanation:

Routing overhead is the amount of information needed to describe the changes in a dynamic network topology. All routers in an OSPF area have identical copies of the topology database and the topology database of one area is hidden from the rest of the areas to reduce routing overhead because fewer routing updates are sent and smaller routing trees are computed and maintained (allow extensive control of routing updates and confine network instability to one area of the network).

Question 4:

Which three features are of OSPF routing protocol? (Choose three)
A – Converge quickly
B – OSPF is a classful routing protocol
C – Identify the best route by use of cost
D – Before exchanging routing information, OSPF routers find out neighbors

Answer: A C D

Question 5:

OSPF routing uses the concept of areas. What are the characteristics of OSPF areas? (Chose three)
A – Each OSPF area requires a loopback interface to be configured
B – Areas may be assigned any number from 0 to 65535
C – Area 0 is called the backbone area
D – Hierarchical OSPF networks do not require multiple areas
E – Multiple OSPF areas must connect to area 0
F – Single area OSPF networks must be configured in area 1

Answer: B C E

Explanation:

I used to think the answers should be C D E and here is my explanation:
OSPF can use an active interface for its router ID, so a loopback interface is not a must -> A is incorrect.
OSPF Area is a 32-bit number so we can use up to 2³² – 1 = 4294967296 – 1 (since Area 0 is the first area). Remember that only process ID is a 16-bit number and ranges from 1 to 65535 -> B is incorrect.
F is incorrect too because single area OSPF netwoks must be configured in Area 0, which is called the backbone area.
For answer D, it is a bit hard to guess what they want to say about “hierarchical” but we should understand “Hierarchical OSPF networks” as “OSPF networks”. D is correct bercause we can only have one area (area 0 – the backbone area) for our networks.
But TT commented on 01-11-2010:
Especially to note on choice B, D, and E:
Choice B: we all know that The areas can be any number from 0 to 4.2 billion and 1 to 65,535 for the Process ID. As choice B specifies ‘area’ (be aware, it’s not saying ‘process id), there is no reason to say that we cannot assign numbers from 0 to 65535 for area # (it is using ‘may be’, not ‘have to be’ or ‘ought to be’). Hence, we do not worry about assigning ’0′.
Choice E: as Area 0 is the backbone, we all understand that any areas in a OSPF network have to be connected to it. And actually this is implicitly saying that multiple areas form a hierarchical OSPF network, as Area 0 being a root and others being its leaves.
Choice D: when it specifies ‘Hierarchical’, at least 2 areas should be required to form such topology (of course that includes Area 0)
Although Choice B is not an absolutely accurate statement since it not only can be assigned up to 65535, it is still a correct answer. And again, it specifies ‘area’, not ‘process id’, so ’0′ can be included. Finally, it would be meaningless to call OSPF a hierarchical network if no more than one area is present.
—————————————————————————————————-
I reviewed the question and think it is a more suitable solution with choice B than choice D, surely it is a tricky question!

Question 6:

Part of the OSPF network is shown below:

Configuration exhibit:
R1 routing commands:
ip route 0.0.0.0 0.0.0.0 serial0/0
router ospf 1
network 172.16.100.0 0.0.0.3 area 0
network 172.16.100.64 0.0.0.63 area 0
network 172.16.100.128 0.0.0.31 area 0
default-information originate
You work as a network technician, study the exhibits carefully. Assume that all router interfaces are operational and correctly configured. In addition, assume that OSPF has been correctly configured on router R2. How will the default route configured on R1 affect the operation of R2?
A – Any packet destined for a network that is not directly connected to router R2 will be dropped immediately
B – Any packet destined for a network that is not directly connected to router R1 will be dropped
C – Any packet destined for a network that is not directly connected to router R2 will be dropped immediately because of the lack of a gateway on R1
D – The network directly connected to a router R2 will not be able to communicate with the 172.16.100.0, 172.16.100.28 and 172.16.100.64 subnetworks.
E – Any packet destined for a network that is not referenced in the routing table of router R2 will be directed to R1. R1 will then send that packet back to R2 and a routing loop will occur

Answer: E

Explanation:

First, notice that the more-specific routes will always be favored over less-specific routes regardless of the administrative distance set for a protocol. In this case, because we use OSPF for three networks (172.16.100.0 0.0.0.3, 172.16.100.64 0.0.0.63, 172.16.100.128 0.0.0.31) so the packets destined for these networks will not be affected by the default route.
The default route configured on R1 “ip route 0.0.0.0 0.0.0.0 serial0/0″ will send any packet whose destination network is not referenced in the routing table of router R1 to R2, it doesn’t drop anything so answers A, B and C are not correct. D is not correct too because these routes are declared in R1 and the question says that “OSPF has been correctly configured on router R2″, so network directly connected to router R2 can communicate with those three subnetworks.
As said above, the default route configured on R1 will send any packet destined for a network that is not referenced in its routing table to R2; R2 in turn sends it to R1 because it is the only way and a routing loop will occur.

CCNA – RIP Questions

Question 1

Which statement about RIPng is true?
A. RIPng allows for routes with up to 30 hops.
B. RIPng is enabled on each interface separately.
C. RIPng uses broadcasts to exchange routes.
D. There can be only one RIPng process per router.

Answer: B

Explanation

RIPng is similar to RIPv2 but is used for IPv6. But unlike RIPv1 and RIPv2, RIPng is enabled on each interface separately. For example:
Router(config)#ipv6 unicast-routing (Enables the forwarding of IPv6 unicast datagrams globally on the router)
Router(config)#interface fa0/0
Router(config-if)#ipv6 rip 9tut enable (9tut is the process name of this RIPng)

Question 2

What are two characteristics of RIPv2? (Choose two)
A. classful routing protocol
B. variable-length subnet masks
C. broadcast addressing
D. manual route summarization
E. uses SPF algorithm to compute path

Answer: B D

Question 3

Refer to the exhibit. Which (config-router) command will allow the network represented on the interface to be advertised by RIP?

router rip version 2 no auto summary ! interface ethernet0 ip address 10.12.6.1 255.255.0.0

A. redistribute ethernet0
B. network ethernet0
C. redistribute 10.12.0.0
D. network 10.12.0.0

Answer: D

Question 4

Refer to the exhibit. What information can be gathered from the output?

RouterA#debug ip rip RIP protocol debugging is on00:34:32: RIP: sending v2 flash update to 224.0.0.9 via FastEthernet8/0 (172.16.1.1) 00:34:32: RIP: build flash update entries 00:34:32: 10.10.1.0/24 via 0.0.0.6, metric 1, tag 0 00:34:32: RIP: sending v2 flash update to 224.0.0.9 via Loopback (10.10.1.1) 00:34:32: RIP: build flash update entries 00:34:32: 10.0.0.0/8 via 0.6.0.0, metric 2, tag 0 00:34:32: 172.16.1.0/24 via 0.0.0.0, metric 1, tag 0 00:34:32: RIP: ignored v2 packet from 16.10.1.1 (sourced from one of our addresses) 06:34:33: RIP: received v2 update from 172.16.1.2 on FastEthernet0/6 66:34:33: 16.6.0.0/8 via 6.0.6.6 in 1 hops 66:34:44: RIP: sending v2 update to 224.6.6.9 via FastEthernet0/0 (172.16.1.1) 66:34:44: RIP: build update entries 66:34:44: 10.10.1.0/24 via 0.0.0.0, metric 1, tag 0

A. One router is running RIPv1.
B. RIP neighbor is 224.0.0.9.
C. The network contains a loop.
D. Network 10.10.1.0 is reachable.

Answer: D

Question 5

Which series of commands will configure router R1 for LAN-to-LAN communication with router R2? The enterprise network address is 192.1.1.0/24 and the routing protocol in use is RIP. (Choose three)

A.
R1 (config)# interface ethernet 0
R1 (config-if)# ip address 192.1.1.129 255.255.255.192
R1 (config-if)# no shutdown
B.
R1 (config)# interface ethernet 0
R1(config-if)#ip address 192.1.1.97 255.255.255.192
R1 (config-if)# no shutdown
C.
R1 (config)# interface serial 0
R1 (config-if)# ip address 192.1.1.4 255.255.255.252
R1 (config-if)# clock rate 56000
D.
R1 (config)# interface serial 0
R1(config-if)#ip address 192.1.1.6 255.255.255.252
R1 (config-it)# no shutdown
E.
R1 (config)# router rip
R1 (config-router)# network 192.1.1.4
R1 (config-router)# network 192.1.1.128
F.
R1 (config)# router rip
R1 (config-router)# version 2
R1 (config-router)# network 192.1.1.0

Answer: A D F

Explanation

First we notice that the ip address of the E0 interface of R2 is 192.1.1.65/26, which has:
+ Increment: 64 (/26 = 1111 1111.1111 1111.1111 1111.1100 0000)
+ Network address: 192.1.1.64
+ Broadcast address: 192.1.1.127
Therefore, the ip address of the E0 interface of R1 cannot belong to this range or the network cannot operate correctly.
In answer A, the ip address of E0 interface of R1 is 192.1.1.129, which does not belong in this range -> A is correct.
In answer B, E0 interface of R1 has the ip address of 192.1.1.97, which belongs in this range -> B is not correct.
The s0 interface of R1 must belong to the same network of s0 interface of R2, which has:
+ Increment: 4 (/30 = 1111 1111.1111 1111.1111 1111.1111 1100)
+ Network address: 192.1.1.4
+ Broadcast address: 192.1.1.7
The ip 192.1.1.5 has been used by s0 of R2 so the only suitable ip address of s0 of R1 is 192.1.1.6 -> C is wrong but D is correct.
Now the last thing we must do is enabling RIP. Because e0 interface of R1 and e0 interface of R2 have the same major network (192.1.1.0/24) so we must use RIP version 2 to support discontiguous network -> F is correct.
For answer E, if we configure 2 networks
R1 (config-router)# network 192.1.1.4
R1 (config-router)# network 192.1.1.128
then these networks will be automatically summarized as 192.1.1.0 network.

Question 6

Refer to the exhibit. Two routers have just been configured by a new technician. All interfaces are up. However, the routers are not sharing their routing tables. What is the problem?

A. Split horizon is preventing Router2 from receiving routing information from Router1.
B. Router1 is configured for RIP version 2, and Router2 is configured for RIP version 1.
C. Router1 has an ACL that is blocking RIP version 2.
D. There is a physical connectivity problem between Router1 and Router2.
E. Router1 is using authentication and Router2 is not.

Answer: B

Explanation

As we can see from the output, Router2 is sending v1 update and ignoring v2 update from neighbor so we can conclude Router2 is running RIPv1. Its neighbor, Router1 (ip address of 192.168.2.1), is running RIPv2.
Notice that router running RIPv2 can “understand” RIPv1 update but router running RIPv1 cannot understand RIPv2 update

Question 7

What is the default routing update period for RIPv2?
A. 15 seconds
B. 30 Seconds
C. 180 Seconds
D. 240 Seconds

Answer: B

Question 8

Refer to the exhibit. The network manager is evaluating the efficiency of the current network design. RIPv2 is enabled on all Layer 3 devices in the network. What network devices participate in passing traffic from the PC at 10.10.1.7 to File Server at 10.20.1.6 in the order that they will forward traffic from source to destination?

A. Switch, Switch2
B. Switch, Switch2, Router2, Switch2
C. Switch1, Router1, Switch1, Switch2
D. Switch1, Router1, Router2, Switch2

Answer: D

Explanation

The PC and File Server are in different VLANs so surely traffic from PC to File Server must go through Router1 but which path will the packet go next, through Router 2 or Switch1? Well, it is a hard question to answer.
As many comments said “the connection between R1 and Switch is Blue, so that means its under Vlan 10, and R2 to Switch 2 is red. The two routers do not have subinterfaces and are not running router on a stick basing on the color of the links” so D should be the correct answer.
Just for your information, I keep this explanation (which supports answer C) but in the exam you should choose D as your answer!
I haven’t had tested it yet but I guess that because there is a VLAN 20 on Switch 1 so Router1 will try to send that packet back to Switch1. If the link between Switch1 and Switch2 is a trunk link then the returned packet will also be sent to this link. Switch 2 receives that packet and it sends to the File Server at VLAN20. So the path will be Switch1 -> Router1 -> Switch1 -> Switch2.
There are some debates about this question but if the routers are properly configured then the packets can go from Switch1 -> Router1 -> Router2 -> Switch2 (D answer) so D can be a correct answer.

Question 9

Refer to the exhibit. Router A has interfaces with addresses 192.168.1.1 and 172.16.1.1. Router B, which is connected to router A over a serial link, has interfaces with address 172.16.1.2 and 10.1.1.2.

Which sequence of commands will configure RIPv2 on router B?
A.
B( config)# router rip
B(config-router)#version 2
B(config-router)# network 172.16.0.0
B(config-router)# network 10.0.0.0
B(config-router)# end
B.
B(config)# router rip 2
B(config-router)# network 172.16.0.0
B(config-router)# network 10.0.0.0
B(config-router)# end
C.
B(config)# router rip
B(config-router)#version 2
B(config-router)# network 172.16.0.0
B(config-router)#network 192.168.1.0
B(config-router)#end
D.
B(config)# router rip version 2
B(config-router)# network 172.16.0.0
B(config-router)# network 10.0.0.0
B(config-router)#end

Answer: A

Question 10

Refer to the exhibit. S0/0 on R1 is configured as a multipoint interface to communicate with R2 and R3 in this hub-and-spoke Frame Relay topology.
While testing this configuration, a technician notes that pings are successful from hosts on the 172.16.1.0/24 network to hosts on both the 172.16.2.0/25 and 172.16.2.128/25 networks. However, pings between hosts on the 172.16.2.0/25 and 172.16.2.128/25 networks are not successful. What could explain this connectivity problem?

A. The ip subnet-zero command has been issued on the R1 router.
B. The RIP v2 dynamic routing protocol cannot be used across a Frame Relay network.
C. Split horizon is preventing R2 from learning about the R3 networks and R3 from learning about the R2 networks.
D. The 172.16.2.0/25 and 172.16.2.128/25 networks are overlapping networks that can be seen by R1, but not between R2 and R3.
E. The 172.16.3.0/29 network used on the Frame Relay links is creating a discontiguous network between the R2 and R3 router subnetworks.

Answer: C

Explanation

The “ip subnet-zero” allows the use of the first subnet but it doesn’t cause this problem and we don’t have that first subnet (like 172.16.0.0/24) so we can’t confirm if the “ip subnet-zero” was used or not -> A is not correct.
Frame-Relay can use RIPv2 with no problem if we configure it correctly -> B is not correct.
In the exhibit above we notice that the s0/0 interface of R1 has not been divided into sub-interfaces so the split horizon will prevent updates from R2 to R3 and vice versa. The split horizon rule states “A router never sends information about a route back in same direction which is original information came”. In this case R2 send an update to S0/0 of R1 so R1 cannot send that update back on S0/0 -> R3 will not learn about networks of R2 (and vice versa) -> C is correct.
172.16.2.0/25 and 172.16.2.128/25 networks are not overlapping networks. They are two different sub-networks -> D is not correct.
RIPv2 is a classless routing protocol so it supports VLSM and discontiguous networks -> E is not correct.

Question 11

Refer to the exhibit. After a RIP route is marked invalid on Router_1, how much time will elapse before that route is removed from the routing table?

Router_1# show ip protocols Routing Protocol is “rip” Sending updates every 30 seconds, next due in 8 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Outgoing update filter list foe all interfaces is not set Incoming update filter list for all interfaces is not set Router 1#

A. 30 seconds
B. 60 seconds
C. 90 seconds
D. 180 seconds
E. 240 seconds

Answer: B

Question 12

Refer to the graphic. Host 1 cannot receive packets from Host 2. Assuming that RIP v1 is the routing protocol in use, what is wrong with the IP configuration information shown? (Choose two)

A. The fa0/1 interface of router R2 has been assigned a broadcast address.
B. The fa0/1 network on router R2 overlaps with the LAN attached to R1.
C. Host 2 has been assigned the incorrect subnet mask.
D. Host 1 has been configured with the 255.255.248.0 subnet mask.
E. Host 2 on router R2 is on a different subnet than its gateway.

Answer: B C

Explanation

The fa0/1 interface of R2 is assigned an IP address of 10.1.40.255/20. It seems to be a broadcast address but it is not. If we calculate the range of this network we will understand why:
Network 10.1.40.255/20
Increment: 16 (/20 = 1111 1111.1111 1111.1111 0000.0000 0000)
Network address: 10.1.32.0
Broadcast address: 10.1.47.255
-> 10.1.40.255/20 is an usable host address -> A is not correct.
The IP address of host 1 (10.1.32.48) belongs to the range of interface fa0/1 on R2 as shown above -> B is correct.
In the topology above, all subnet masks are /20 (255.255.240.0) excepting the subnet mask of Host 2 (255.255.252.0)  so C can be incorrect.
The subnet mask of Host 1 is 255.255.240.0, not 255.255.248.0 -> D is not correct.
Host 2 is not on a different subnet than its gateway even if the subnet mask 255.255.252.0 is used. Let’s analyze the range of Host 2 network:
Network 10.1.40.96/22
Increment: 4
Network address: 10.1.40.0
Broadcast address: 10.1.43.255
Its gateway (10.1.40.255) is still belongs to this range -> E is not correct.
Note: In this question, C is the best suitable answer after eliminating A, D, E answers. But in fact Host 2 can ping its gateway because they are on the same subnet.

Question 13

What two things will a router do when running a distance vector routing protocol? (Choose two)
A. Send periodic updates regardless of topology changes.
B. Send entire routing table to all routers in the routing domain.
C. Use the shortest-path algorithm to the determine best path.
D. Update the routing table based on updates from their neighbors.
E. Maintain the topology of the entire network in its database.

Answer: A D

Question 14

Use the output from the router shown in the graphic above to determine which of the following are correct. (Choose two)
A. Router John uses a link-state routing protocol.
B. Router John will receive routing updates on the Serial0/0 interface.
C. Router John will receive routing updates on the Serial0/1 interface.
D. Router John will send routing updates out the Serial0/0 interface.
E. Router John will send routing updates out the FastEthernet0/0 interface.
F. Router John will send routing updates out the Serial0/1 interface.

Answer: B D

Question 15

What can be determined from the line of show ip route output shown in the exhibit? (Choose two)
R 10.10.10.8 [120/2] via 10.10.10.6,00:00:25, Serial0/1
A. The next routing update can be expected in 35 seconds.
B. The IP address 10.10.10.6 is configured on S0/1.
C. The IP address 10.10.10.8 is configured on S0/1.
D. This route is using the default administrative distance.
E. The 10.10.10.8 network is two hops away from this router.

Answer: D E

Explanation

From the output, we can see 2 parameters [120/2]. The first is the administrative distance of the routing protocol being used. In this case it is RIP (symbolized by the letter “R”). Because 120 is also the default administrative distance value of RIP -> D is correct.
In RIP, the metric is hop count so “2″ means the network 10.10.10.8 is two hops (routers) away from this router.

CCNA – IP Routing Questions 2

Question 1

Refer to the exhibit. Host A is to send data to Host B. How will Router1 handle the data frame received from Host A? (Choose three)

A. Router1 will strip off the source MAC address and replace it with the MAC address on the forwarding FastEthernet interface.
B. Router1 will strip off the source IP address and replace it with the IP address on the forwarding FastEthernet interface.
C. Router1 will strip off the destination MAC address and replace it with the MAC address of Host B.
D. Router1 will strip off the destination IP address and replace it with the IP address of Host B.
E. Router1 will forward the data frame out interface FastEthernet0/1.
F. Router1 will forward the data frame out interface FastEthernet0/2.

Answer: A C F

Explanation

While transferring data through many different networks, the source and destination IP addresses are not changed. Only the source and destination MAC addresses are changed. So in this case, Host A will use the IP address of Host B and the MAC address of Fa0/0 interface to send data. When the router receives this data, it replaces the source MAC address with it own Fa0/2 interface’s MAC address and replaces the destination MAC address with Host B’s MAC address before sending to Host B -> A, C and F are correct.

Question 2

What is an appropriate use of a default route?
A. to provide routing to a local web server
B. to provide routing from an ISP to a stub network
C. to provide routing that will override the configured dynamic routing protocol
D. to provide routing to a destination that is not specified in the routing table and which is outside the local network

Answer: D

Explanation

Default routes are used to direct packets addressed to networks not explicitly listed in the routing table. An example of default route is:
Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.1
(Notice that the network address of default route is 0.0.0.0 0.0.0.0)

Question 3

A medium-sized company has a Class C IP address. It has two Cisco routers and one non-Cisco router.
All three routers are using RIP version 1.
The company network is using the block of 198.133.219.0/24.
The company has decided it would be a good idea to split the network into three smaller subnets and create the option of conserving addresses with VLSM.
What is the best course of action if the company wants to have 40 hosts in each of the three subnets?
A. Convert all the routers to EIGRP and use 198.133.219.32/27, 198.133.219.64/27, and 198.133.219.92/27 as the new subnetworks.
B. Maintain the use of RIP version 1 and use 198.133.219.32/27, 198.133.219.64/27, and 198.133.219.92/27 as the new subnetworks.
C. Convert all the routers to EIGRP and use 198.133.219.64/26, 198.133.219.128/26, and 198.133.219.192/26 as the new subnetworks.
D. Convert all the routers to RIP version 2 and use 198.133.219.64/26, 198.133.219.128/26, and 198.133.219.192/26 as the new subnetworks.
E. Convert all the routers to OSPF and use 198.133.219.16/28, 198.133.219.32/28, and 198.133.219.48/28 as the new subnetworks.
F. Convert all the routers to static routes and use 198.133.219.16/28, 198.133.219.32/28, and 198.133.219.48/28 as the new subnetworks.

Answer: D

Explanation

RIP version 1 does not support VLSM so we have to convert into RIPv2, OSPF or EIGRP -> B is not correct.
But EIGRP is a Cisco-proprietary routing protocol so it can not be used in a non-Cisco router -> A and C are not correct.
To support 40 hosts per subnet we need a subnet mask of /26 or lower (which leaves 6 bits 0 and 2⁶ = 64 > 40 hosts). Therefore a subnet mask of /28 is not suitable in this case -> E & F are not correct.

Question 4

Refer to the exhibit. Which command will created a default route on RouterB to reach all networks beyond RouterA?

A. ip route 0.0.0.0 0.0.0.0 192.168.2.2
B. ip route 192.168.1.0 255.255.255.0 192.168.2.1
C. ip route 192.168.1.0 255.255.255.0 s0/0/0
D. ip route 10:0.0.0 255.255.255.0 s0/0/0
E. ip route 0.0.0.0 255.255.255.0 192.168.2.2

Answer: A

Explanation

Notice that in the static (or default) route we need to specify the exit-interface (local on that router) or the next-hop IP address (of a directly connected router) -> A is correct.

Question 5

Refer to the exhibit. S0/0 on R1 is configured as a multipoint interface to communicate with R2 and R3 in the hub-and-spoke Frame Relay topology. While testing this configuration, a technician notes that pings are successfully from hosts on the 172.16.1.0/24 network to hosts on both the 172.16.2.0/25 and 172.16.0.2.128/25 networks. However, pings between hosts on the 172.16.2.0/25 and 172.16.2.128/25 network are not successful. What could explain this connectivity problem?

A. The ip subnet-zero command has been issued on the R1 router.
B. The RIPv2 dynamic routing protocol cannot be used across a Frame Relay network.
C. Split horizon is preventing R2 from learning about the R3 networks and R3 from learning about R2 networks.
D. The 172.16.2.0/25 and 172.16.2.128/25 networks are overlapping networks that can be seen by R1, but not between R2 and R3.
E. The 172.16.3.0/29 network used on the Frame Relay links is creating a discontiguous network between the R2 and R3 router subnetworks.

Answer: C

Explanation

The split horizon rule states “a router never sends information about a route back in same direction which is original information came”. In this case it means whenR3 sends update to R1 via s0/0, R1 does not send any update for same network out of interface s0/0. To solve this problem we can configure sub-interfaces on s0/0 or explicitly allow the update to be sent back on the same interface.

Question 6

S0/0 on R1 is configured as a multipoint interface to communicate with R2 and R3 in the hub-and-spoke Frame Relay topology shown in the exhibit. Originally, static routes were configured between these routers to successfully route traffic between the attached networks. What will need to be done in order to use RIPv2 in place of the static routes?

A. Configure the no ip subnet-zero command on R1, R2, and R3.
B. Dynamic routing protocols such as RIPv2 cannot be used across Frame Relay networks.
C. Configure the S0/0 interface on R1 as two subinterfaces and configure point-to-point links to R2 and R3.
D. Change the 172.16.2.0/25 and 172.16.2.128/25 subnetworks so that at least two bits are borrowed from the last octet.
E. Change the network address configuration to eliminate the discontiguous 172.16.2.0/25 and 172.16.2.128/25 subnetwork.

Answer: C

Explanation

Same as Question 5

Question 7

Refer to the exhibit. A network associate has configured the internetwork that is shown in the exhibit, but has failed to configure routing properly.

Which configuration will allow the hosts on the Branch LAN to access resources on the HQ LAN with the least impact on router processing and WAN bandwidth?
A.
HQ(config)# ip route 192.168.1.0 255.255.255.0 192.168.2.5
Branch(config) # ip route 172.16.25.0 255.255.255.0 192.168.2.6
B.
HQ(config)# router rip
HQ(config-router)# network 192.168.2.0
HQ(config-router)# network 172.16.0.0
Branch(config)# router rip
Branch(config-router) # network 192.168.1.0
Branch(config-router)# network 192.168.2.0
C.
HQ(config)# router eigrp 56
HQ(config-router)# network 192.168.2.4
HQ(config-router)# network 172.16.25.0
Branch(config)# router eigrp 56
Branch(config-router)# network 192.168.1.0
Branch(config-router) # network 192.168.2.4
D.
HQ(config)# router ospf 1
HQ(config-router)# network 192.168.2.4 0.0.0.3 area 0
HQ(config-router)# network 172.16.25.0 0.0.0.255 area 0
Branch(config)# router ospf 1
Branch(config-router)# network 192.168.1.0 0.0.0.255 area 0

Answer: A

Explanation

By configuring static route, we can minimize the router processing and WAN bandwidth.

Question 8

Refer to the exhibit. The network administrator requires easy configuration options and minimal routing protocol traffic. Which two options provide adequate routing table information for traffic that passes between the two routers and satisfy the requests of the network administrator?(choose two)

A. a dynamic routing protocol on InternetRouter to advertise summarized routers to CentralRouter.
B. a dynamic routing protocol on CentralRouter to advertise summarized routers to InternetRouter.
C. a static route on InternetRouter to direct traffic that is destined for 172.16.0.0/16 to CentralRouter.
D. a dynamic routing protocol on InternetRouter to advertise all routes to CentralRouer.
E. a dynamic routing protocol on CentralRouer to advertise all routes to InternetRouter
F. a static, default route on CentralRouter that directs traffic to InternetRouter.

Answer: C F

Question 9

A router receives information about network 192.168.10.0/24 from multiple sources. What will the router consider the most reliable information about the path to that network?
A. an OSPF update for network 192.168.0.0/16
B. a static router to network 192.168.10.0/24
C. a static router to network 192.168.10.0/24 with a local serial interface configured as the next hop
D. a RIP update for network 192.168.10.0/24
E. a directly connected interface with an address of 192.168.10.254/24
F. a default route with a next hop address of 192.168.10.1

Answer: E

Question 10

Which parameter can be tuned to affect the selection of a static route as a backup when a dynamic protocol is also being used?
A. link bandwidth
B. hop count
C. link cost
D. administrative distance
E. link delay

Answer: D

Question 11

Which statement is true, as relates to classful or classless routing?
A. RIPV1 and OSPF are classless routing protocols.
B. Classful routing protocols send the subnet mask in routing updates.
C. Automatic summarization at classful boundaries can cause problems on discontiguous networks.
D. EIGRP and OSPF are classful routing protocols and summarize routes by default.

Answer: C

Question 12

Which two are advantages of static routing when compared to dynamic routing? (choose two)
A. Security increases because only the network administrator may change the routing tables.
B. Configuration complexity decreases as network size increases.
C. Routing updates are automatically sent to neighbors.
D. Route summarization is computed automatically by the router.
E. Routing traffic load is reduced when used in stub network links.
F. An efficient algorithm is used to build routing tables using automatic updates.
G. Routing tables adapt automatically to topology changes.

Answer: A E

Question 13

The speed of all serial links is E1 and the speed of the all other links is 100Mb/s. A static route will be established on the Manchester router to direct traffic toward to the internet over the most direct path available. What configuration of the Manchester router will establish a route toward to the internet for traffic from workstation on the Manchester LAN?

A. ip route 0.0.0.0 255.255.255.0 172.16.100.2
B. ip route 0.0.0.0 255.255.255.252 128.107.1.1
C. ip route 0.0.0.0 0.0.0.0 128.107.1.1
D. ip route 0.0.0.00.0:0:0 172.16.100.1
E. ip route 0.0.0.0 255.255.255.255 172.16.100.2
F. ip route 0.0.0.0 0.0.0.0 172.16.100.2

Answer: F

Explanation

Maybe “the most direct path available” here means via R2 because it is directly connected with the Internet while the London path needs to go through R1. So we need a command to send traffic to R2 and the correct command is “ip route 0.0.0.0 0.0.0.0 172.16.100.2″.