Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 331:

  Given the accompanying output, which additional command is needed to redistribute IGRP into EIGRP?

  Router eigrp 123 Network 10.10.10.0 No auto-summary ! Router igrp 123 Network 172.16.0.0 Network 172.17.0.0

  A. Under the router igrp mode add redistribute eigrp 123
  B. Under the router eigrp mode add redistribute igrp 123
  C. Under the router eigrp mode add redistribute igrp 123 subnets
  D. None, EIGRP and IGRP are automatically redistributed in this instance.
  D. None, EIGRP and IGRP are automatically redistributed in this instance.

  ---

  The point of this question is redistribute IGRP into EIGRP. When redistributing IGRP into EIGRP, there is a feature that they are automatically redistributed if they have same autonomous system number; in opposite, they need to manually redistributed if they have different autonomous system number..

• Question 332:

  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?

  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.
  B. Two routers have the same OSPF router ID.

  ---

  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.

  Reference: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080117102.shtml

• Question 333:

  Router R1, a branch router, connects to the Internet using DSL. Some traffic flows through a GRE and IPsec tunnel, over the DSL connection, and into the core of an Enterprise network. The branch also allows local hosts to communicate directly with public sites in the Internet over this same DSL connection. Which of the following answers defines how the branch NAT config avoids performing NAT for the Enterprise directed traffic but does perform NAT for the Internet-directed traffic?

  A. By not enabling NAT on the IPsec tunnel interface
  B. By not enabling NAT on the GRE tunnel interface
  C. By configuring the NAT-referenced ACL to not permit the Enterprise traffic
  D. By asking the ISP to perform NAT in the cloud
  C. By configuring the NAT-referenced ACL to not permit the Enterprise traffic

  ---

  The NAT configuration acts only on packets permitted by a referenced ACL. As a result, the ACL can permit packets destined for the Internet, performing NAT on those packets. The ACL also denies packets going to the Enterprise, meaning that the router does not apply NAT to those packets.

• Question 334:

  Which three are advantages to creating multiple areas in OSPF? (Choose three.)

  A. less frequent SPF calculations
  B. fewer hello packets
  C. smaller routing tables
  D. reduced LSU overhead
  E. fewer adjacencies needed
  A. less frequent SPF calculations
  C. smaller routing tables
  D. reduced LSU overhead

  ---

  OSPF routers within an area only need to know about other routers within their own area, not outside their area, and all OSPF routers within a given area share the same link state database. This keeps the routing tables small enough to

  prevent processing bottlenecks from occurring.

  Also SPF only needs to calculate paths to routers within that area.

  If a router receives an LSA with old information then it will send a LSU to the sender to update the sender with the newer information. The Link State Update (LSU) holds the LSAs. Instead of sending multiple LSUs the ABR / ASBR

  summarizes a route and sends only one LSU-.

  Note: The LSA has a 30 minute timer that causes the router to send an LSU to everyone on the network once it ages out.

• Question 335:

  Which three statements are true regarding EIGRP? (Choose three.)

  A. By default, EIGRP performs auto-summarization across classful network boundaries.
  B. EIGRP uses an area hierarchy to increase network scalability.
  C. To speed convergence, EIGRP attempts to maintain a successor and feasible successor path for each destination.
  D. EIGRP uses hellos to establish neighbor relationships.
  E. By default, EIGRP uses the Dijkstra algorithm to determine the best path to a destination network based on bandwidth and delay.
  A. By default, EIGRP performs auto-summarization across classful network boundaries.
  C. To speed convergence, EIGRP attempts to maintain a successor and feasible successor path for each destination.
  D. EIGRP uses hellos to establish neighbor relationships.

  ---

  Reference:

  http://ptgmedia.pearsoncmg.com/images/1587131706/samplechapter/1587131706content.pdf (See page 66 which is the 2nd page of this pdf)

• Question 336:

  Which statement is true about EBGP?

  A. An internal routing protocol can be used to reach an EBGP neighbor.
  B. The next hop does not change when BGP updates are exchanged between EBGP neighbors.
  C. A static route can be used to form an adjacency between neighbors.
  D. EBGP requires a full mesh.
  C. A static route can be used to form an adjacency between neighbors.

  ---

  When BGP is running between routers in different autonomous systems, it is called External BGP (EBGP). When BGP is running between routers in the same AS, it is called Internal BGP (IBGP). BGP allows the path that packets take to be manipulated by the AS, as described in this module. It is important to understand how BGP works to avoid creating problems for your AS as a result of running BGP.

• Question 337:

  Refer to the exhibit.

  

  If R1 is configured for 6to4 tunneling, what will the prefix of its IPv6 network be?

  A. 1723:1100:1::/48
  B. FFFF:AC1F:6401::/16
  C. AC1F:6401::/32
  D. 2002:AC1F:6401::/48
  E. 3FFE:AC1F:6401::/32
  D. 2002:AC1F:6401::/48

  ---

  Reference: http://networklessons.com/ipv6/how-to-configure-ipv6-automatic-6to4-tunneling/

• Question 338:

  Which two statements are EIGRP characteristics? (Choose two.)

  A. Updates are sent as multicast.
  B. Updates are sent as broadcast.
  C. Metric values are represented in a 32-bit format for granularity.
  D. LSAs are sent to adjacent neighbors.
  A. Updates are sent as multicast.
  C. Metric values are represented in a 32-bit format for granularity.

  ---

  EIGRP uses the same algorithm for metric calculation as IGRP, but represents values in 32- bit format to give additional granularity. EIGRP supports unequal metric load balancing, which allows administrators to better distribute traffic flow in their networks. Multicast and unicast: EIGRP uses multicast and unicast, rather than broadcast. The multicast address used for EIGRP is 224.0.0.10.

• Question 339:

  Refer to the exhibit.

  All routers have simultaneously been reloaded and the DR election has concluded as expected. What state is RTB in?

  A. 2WAY/DROTHER
  B. 2WAY/BDR
  C. 2WAY/DR
  D. FULL/DROTHER
  E. FULL/BDR
  F. FULL/DR
  D. FULL/DROTHER

  ---

  The point of this question is about the select principles of DR and BDR. DR and BDR election is done via the Hello protocol. Hello packets are exchanged via IP multicast packets (Appendix B) on each segment. The router with the highest OSPF priority on a segment will become the DR for that segment. The same process is repeated for the BDR. In case of a tie, the router with the highest RID will win. The default for the interface OSPF priority is one. Remember that the DR and BDR concepts are per multiaccess segment. Setting the ospf priority on an interface is done using the ip ospf priority interface command. In this case, all routers have the same priority, but RTD has the highest RID, and RTC was followed, so RTC was the BDR.

• Question 340:

  Drag each OSPF state to the correct definition.

  Select and Place: