10 04 2014

QUESTION 31
Which statement is true about OSPF Network LSAs? Select the best response.

A.    They are originated by every router in the OPSF network. They include all routers on the link, interfaces,
the cost of the link, and any known neighbor on the link.
B.    They are originated by the DR on every multi-access network. They include all attached routers including
the DR itself.
C.    They are originated by Area Border Routers and are sent into a single area to advertise destinations
outside that area.
D.    They are originated by Area Border Router and are sent into a single area to advertise an Autonomous
System Border Router.

Answer: B

Explanation:
The point of this question is OSPF Network LSAs
The feature of OSPF Network LSAs is that they are generated by DR, and DR only exist on multi- access network, the use of OSPF Network LSAs is that it list all neighbors around and send it to every router which run OSPF.
Incorrect Answer: OSPF Network LSAs are not originated by Area Border Routers.

QUESTION 32
Refer to the exhibit. Routing updates for the 192.168.1.0 network are being received from all three neighbors. Which statement is correct regarding the result of the configuration shown?

A.    The router will prefer the next hop of 172.16.1.1 for packets destined for the 192.168.1.0 network.
B.    The router will prefer the next hop of 172.26.1.1 for packets destined for the 192.168.1.0 network.
C.    The router will advertise the 192.168.1.0 network only to 172.30.1.1.
D.    The router will advertise the 192.168.1.0 network only to 172.26.1.1.
E.    The router will prefer the next hop of 172.26.1.1 for packets except those destined for the

Answer: B
Explanation:
The local-preference of the next hop 172.26.1.1 is set to 200, which is higher than the default value (100) so this path is preferred for packets destined to the 192.168.1.0 network.

QUESTION 33
Refer to the exhibit. OSPF is configured on all routers in the network. On the basis of the show ip ospf neighbor output, what prevents R1 from establishing a full adjacency with R2?

A.    Router R1 will only establish full adjacency with the DR and BDR on broadcast multiaccess networks.
B.    Router R2 has been elected as a DR for the broadcast multiaccess network in OSPF area
C.    Routers R1 and R2 are configured as stub routers for OSPF area 1 and OSPF area 2.
D.    Router R1 and R2 are configured for a virtual link between OSPF area 1 and OSPF area 2.
E.    The Hello parameters on routers R1 and R2 do not match.

Answer: A
Explanation:
From the output, we learn that R4 is the DR and R3 is the BDR so other routers will only establish full adjacency with these routers. All other routers have the two-way adjacency established.

QUESTION 34
Refer to the exhibit. On the basis of the configuration provided, how are the Hello packets sent by R2 handled by R5 in OSPF area 5?

A.    The Hello packets will be exchanged and adjacency will be established between routers R2 and R5.
B.    The Hello packets will be exchanged but the routers R2 and R5 will become neighbors only.
C.    The Hello packets will be dropped and no adjacency will be established between routers R2 and R5.
D.    The Hello packets will be dropped but the routers R2 and R5 will become neighbors.

Answer: C
Explanation:
The point of this question is the conditions of OSPF establish adjacency relationship. For ospf, the optional capabilities must set the same between neighbors, but from the exhibit, R5 was configured as a stub area while R2 in area 0 is a normal area. So there will be no adjacent relationship established between routers R2 and R5.

QUESTION 35
Refer to the exhibit. You are the network administrator of the Route.com company. You have been tasked to implement a hub and spoke EIGRP topology over Frame Relay to provide connectivity between the networks at headquarters and all 300 spokes.
Before you begin the actual implementation, which three pieces of information are more important to know than the others? (Choose three.)

A.    the Committed Information Rate of all the Frame Relay PVCs
B.    the Cisco IOS version running on all the routers
C.    the router model number of all the spoke routers
D.    the number of HQ networks connected behind the headquarter routers
E.    the routing policy, such as whether or not the spokes can be used as backup transient point between
the two headquarter routers

Answer: ABE
Explanation:
You have to know the committed information rate because it is a bandwidth associated with logical connection in a PVC. You also need to know the IOS version on all routers so that there is no conflict in versions. As per the topology, you need to know the routing policy because it will be used as a backup transient point between headquarter routers

QUESTION 36
Refer to the exhibit. The Route.com company is running EIGRP between all the routers. Currently, if one of the LAN links (LAN1 or LAN2) at the headquarters flaps (goes up and down), the HQ-RTR1 and HQ-RTR2 routers will experience high CPU usage and have a long EIGRP convergence time. As the new network administrator, you are asked to investigate this situation and determine if there is a quick way to resolve this issue.
Which is the most important thing that you can quickly verify first to resolve this issue?

A.    Verify that the bandwidth setting on all WAN links is correct.
B.    Verify that the HQ-RTR1 and HQ-RTR2 routers are configured to send only a default route to all the
spoke routers.
C.    Verify that the HQ-RTR1 and HQ-RTR2 routers are configured for EIGRP Nonstop Forwarding.
D.    Verify that all the spoke routers are configured for autosummarization.
E.    Verify that all the spoke routers are configured as EIGRP stub.

Answer: E
Explanation:
Stub routing is commonly used in a hub and spoke network topology. In a hub and spoke network, one or more end (stub) networks are connected to a remote router (the spoke) that is connected to one or more distribution routers (the hub). The remote router is adjacent only to one or more distribution routers. The only route for IP traffic to follow into the remote router is through a distribution router. This type of configuration is commonly used in WAN topologies where the distribution router is directly connected to a WAN. The distribution router can be connected to many more remote routers. Often, the distribution router will be connected to 100 or more remote routers. In a hub and spoke topology, the remote router must forward all nonlocal traffic to a distribution router, so it becomes unnecessary for the remote router to hold a complete routing table. Generally, the distribution router need not send anything more than a default route to the remote router.
When using the EIGRP Stub Routing feature, you need to configure the distribution and remote routers to use EIGRP, and to configure only the remote router as a stub. Only specified routes are propagated from the remote (stub) router. The router responds to queries for summaries, connected routes, redistributed static routes, external routes, and internal routes with the message "inaccessible." A router that is configured as a stub will send a special peer information packet to all neighboring routers to report its status as a stub router.
Any neighbor that receives a packet informing it of the stub status will not query the stub router for any routes, and a router that has a stub peer will not query that peer. The stub router will depend on the distribution router to send the proper updates to all peers.

QUESTION 37
You have just completed an OSPF implementation. While executing your verification plan, you determine that R1 is not able to establish full OSPF adjacency with R2. The show ip ospf neighbor command output on R1 shows that R2 is stuck in the INIT state.
What could be the cause of this problem? Select the best response.

A.    DR and BDR election errors between R1 and R2.
B.    The R2 router has not received the OSPF hello packets from the R1 router.
C.    Mismatched interface maximum transmission unit (MTU) configuration between the R1 and R2.
D.    Mismatched OSPF hello interval configuration between the R1 and R2.
E.    Corrupted LSAs exchanges between the R1 and R2.

Answer: B
Explanation:
When a router receives an OSPF Hello from a neighbor, it sends the Hello packet by including that neighbor’s router ID in the Hello packet. If the neighbor does not receive this packet (means that it doesn’t see itself in this packet), it will be stuck in INIT state. INIT state can be understood as a one-way Hello.

QUESTION 38
Refer to the exhibit. When you examine the routing table of R1 and R4, you are not able to see the R1 Ethernet subnet on the R4 routing table. You are also not able to see the R4 Ethernet subnet on the R1 routing table.
Which configuration change should be made to resolve this issue? Select the routers where the configuration change will be required, and select the required EIGRP configuration command(s).
(Choose two.)

A.    R1 and R4
B.    R2 and R3
C.    ip summary-address eigrp 1 10.1.1.0 255.255.255.0 and ip summary-address eigrp 1
D.    variance 2
E.    eigrp stub connected
F.    no auto-summary

Answer: BF
Explanation:
Of course, the routing is going through R2 and R3 to reach R4. So the two routers that need configuration change are R2 and R3. Also you need to set auto-summary to No. The no auto-summary command configures classless routing protocols such as RIPv2 and EIGRP to really act as classless because by default they’re classfull.

QUESTION 39
You have completed an OSPF implementation, and you are verifying OSPF operation. During this verification, you notice that the OSPF route of 172.16.10.0 is repeatedly appearing and disappearing from the routing table. Further investigation finds that the OSPF CPU utilization is very high and the routers are constantly performing SPF calculations.
You determine that 172.16.20.2 is the source of the 172.16.10.0 route. Using the show ip ospf database router 172.16.20.1 command, you notice that when this show command is performed repeatedly, the contents of the LSA change every few seconds. What could be the cause of this problem? Select the best response.

A.    OSPF authentication errors between some of the routers.
B.    Two routers have the same OSPF router ID.
C.    Issues with mistuned OSPF timers.
D.    OSPF LSA pacing issues between some of the routers.
E.    OSPF neighbor adjacency problems between some of the routers.

Answer: B
Explanation:
When two routers use the same router ID in an OSPF domain, routing possibly does not work
correctly. Cisco bug IDs CSCdr61598 and CSCdu08678 enhance the detection and reporting mechanisms of duplicate router IDs. Access the Bug Toolkit (registered customers only) in order to view additional information about these Cisco bug ID.

QUESTION 40
Refer to the exhibit. ROUTE.com has just implemented this EIGRP network. A network administrator came to you for advice while trying to implement load balancing across part of their EIGRP network. If the variance value is configured as 2 on all routers and all other metric and K values are configured to their default values, traffic from the Internet to the data center will be load balanced across how many paths?

A.    1
B.    2
C.    3
D.    4
E.    5

Answer: C
Explanation:
First we should list all the paths from the Internet to the data center:
+ A-B-C-H with a metric of 70 (40 + 15 + 15)+ A-B-E-H with a metric of 60 (40+10+10)+ A-D-E-H with a metric of 30 (10+10+10)+ A-D-E-B-C-H with a metric of 60 (10+10+10+15+15)+ A-D-E-F- G-H with a metric of 70 (10+10+10+20+20)+ A-F-G-H with a metric of 60 (20+20+20)+ A-F-E-H with a metric of 40 (20+10+10)
So the path A-D-E-H will be chosen because it has the best metric. But EIGRP can support unequal cost path load balancing. By configuring the variance value of 2, the minimum metric is increased to 60 (30 * 2) and all the routes that have a metric of less than or equal to 60 and satisfy the feasibility condition will be used to send traffic. Besides the main path A-D-E-H we have 4 more paths that have the metric of less than or equal to 60 (we also include the Advertised Distances of these routes for later comparison):
+ A-B-E-H with an AD of 20+ A-D-E-B-C-H with an AD of 50+ A-F-G-H with an AD of 40+ A-F-E-H with an AD of 20
Now the last thing we need to consider is the feasible condition. The feasible condition states:
"To qualify as a feasible successor, a router must have an AD less than the FD of the current successor route"
The FD of the current successor route here is 30 (notice that the variance number is not calculated here). Therefore there are only 2 paths that can satisfy this conditions: the path A-B-E-H & A-F-E- H.
In conclusion, traffic from the Internet to the data center will be load balanced across 3 paths, including the main path (successor path)

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