Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 61:

  Which statement is true about an IPsec/GRE tunnel?

  A. The GRE tunnel source and destination addresses are specified within the IPsec transform set.
  B. An IPsec/GRE tunnel must use IPsec tunnel mode.
  C. GRE encapsulation occurs before the IPsec encryption process.
  D. Crypto map ACL is not needed to match which traffic will be protected.
  C. GRE encapsulation occurs before the IPsec encryption process.

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  Reference: http://www.cisco.com/en/US/ts/fn/620/fn62394.html

• Question 62:

  Refer to the exhibits. What can be done to fix the problem?

  RouterA#debug ip ospf events OSPF events debugging is on RouterA#

  04:43:16: OSPF. Rcv pkt from 10.3.0.2, Ethernet0/1, area 0.0.0.1 mismatch area 0.0.0.2 in the header

  04:43:19:

  OSPF. Rcv hello from 10.100.100.3 area 0 from Ethernet0/0 10.1.0.1

  04:43:19:

  OSPF. End of hello processing

  A. Change router B E0/1 interface to area 0.
  B. Change router A interface E0/1 to area 0.0.0.2.
  C. Configure the E0/1 interfaces of router A and router B to be in area 0.
  D. Shut down the E0/1 interfaces in router A and router B as OSPF does not allow "back doors" between areas.
  E. Remove the E0/1 interfaces in router A and router B from the OSPF process. Use static routes to route data directly from router A to router B to avoid passing data through router C in area 0.
  C. Configure the E0/1 interfaces of router A and router B to be in area 0.

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  Reference:

  http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094e9e.shtml (See topic: the backbone and area 0)

• Question 63:

  Which attribute must exist in the BGP update packet?

  A. LOCAL_ PREF
  B. AGGREGATOR
  C. AS_Path
  D. Weight
  C. AS_Path

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  Origin, AS_Path, Next_Hop are well-known mandatory BGP attributes that all BGP Updates must include.

  Note:

  There are 4 BGP attribute types:

  + Well-known Mandatory: recognized by all implementations of BGP and must appear in a BGP update message. If missing, a notification error will be generated. + Well-Known Discretionary: recognized by all implementations of BGP but may not be sent in the BGP update message (include LOCAL_PREF, ATOMIC_AGGREGATOR). + Optional Transitive: may or may not be recognized by all BGP implementations. Because the attribute is transitive, BGP accepts and advertises the attribute even if it is not recognized (include Community attribte). + Optional Nontransitive: may or may not be recognized by all BGP implementations. Whether or not the receiving BGP router recognizes the attribute, it is nontransitive and is not passed along to other BGP peers (include MED).

• Question 64:

  Refer to the exhibit.

  

  On the basis of the configuration that is provided, how would the BGP updates that come from router R1 be replicated inside autonomous system 65200?

  A. All BGP updates that are received on router R2 will be sent to routers R3 and R4. Routers R3 and R4 will then forward those BGP updates to router R5.
  B. All BGP updates that are received on router R2 will not be sent to routers R3 and R4.
  C. All BGP updates that are received on router R2 will be sent directly to router R5.
  D. None of the BGP updates that are received on router R2 will ever be received by router R5.
  D. None of the BGP updates that are received on router R2 will ever be received by router R5.

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  All BGP updates that are received on router R2 will be sent to routers R3 and R4 but R3 and R4 will not forward those BGP updates to R5. This is called the BGP split-horizon rule (which states that a route learned from one IBGP neighbor will

  not be advertised to another IBGP neighbor) .

  The BGP updates received on router R2 will be sent to R3 and R4 without violating the BGP split-horizon rule because R2 receives updates from an EBGP (R1), not IBGP.

  From the configuration of R2, we learn that R2 did not establish neighbor relationship with R5 so they are not neighbors -> no BGP updates will be sent from R2 to R5.

  The BGP split-horizon rule prevents updates received on R2 from being sent to R5 is correct.

• Question 65:

  Refer to the exhibit. Which two Cisco IOS commands on R2 would verify its OSPF neighbor relationships? (Choose two.)

  

  A. show ip ospf
  B. show ip ospf interface
  C. show ip ospf neighbor
  D. show ip ospf database
  E. show ip ospf statistics
  F. show running-config | begin router ospf
  B. show ip ospf interface
  C. show ip ospf neighbor

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  The show ip ospf interface command shows us information about the neighbor count and adjacent neighbor count:

  

  The show ip ospf neighbor command shows us the role of each neighbor (DR, BDR, DROTHER).

  

• Question 66:

  Which one of the following statements about BGP is FALSE?

  A. BGP uses TCP port 179.
  B. BGP ensures reliability of updates by using the reliable transport services of TCP.
  C. The network command with the mask option never installs a prefix into the BGP table unless there is a matching prefix exists in the IP route table.
  D. A TCP connection is required before exchanging updates.
  E. BGP uses notification and the update messages to establish and maintain the BGP neighbor relationship.
  E. BGP uses notification and the update messages to establish and maintain the BGP neighbor relationship.

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  An underlying connection between two BGP speakers is established before any routing information is exchanged. This connection takes place on TCP port 179. Unlike other routing protocols, the router must be manually configured with the neighbor information on both sides of the connection (which is FALSE in this question)

• Question 67:

  Which three statements are true when configuring redistribution for OSPF? (Choose three)

  A. The default metric is 10.
  B. The default metric is 20.
  C. The default metric type is 2.
  D. The default metric type is 1.
  E. Subnets do not redistribute by default.
  F. Subnets redistribute by default.
  B. The default metric is 20.
  C. The default metric type is 2.
  E. Subnets do not redistribute by default.

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  Reference:

  http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094e9e.shtml (see redistributing routes into OSPF)

• Question 68:

  Which BGP command provides the router ID, local preference, next hop, and BGP path in its output?

  A. show ip route bgp
  B. show ip bgp
  C. show ip bgp neighbors
  D. show ip bgp summary
  B. show ip bgp

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  The "show ip bgp" command is used to display entries in the BGP routing table. An example of the "show ip bgp" output is shown below:

  

  In the output you can see the router ID, local preference, next hop, and BGP path.

• Question 69:

  Given the network diagram.

  

  Which address would successfully summarize only the networks seen?

  A. 192.168.0.0/24
  B. 192.168.8.0/20
  C. 192.168.8.0/21
  D. 192.168.12.0/20
  E. 192.168.16.0/21
  F. These networks cannot be summarized.
  C. 192.168.8.0/21

  ---

  let's suppose it is a /20 then we would have addresses from 192.168.0.1 to 192.168.15.255 Now let's suppose it is a /21 then we would have addresses from 192.168.8.1 to 192.168.15.255 So both summaries encompass the networks we want to summarize but the second one is the most restrictive one as it only encompasses the networks we were asked to summarize and not others so it is the correct summary. In fact just count the number of subnets which is 8 and find the exponent of 2 which is 8, that gives you 3 and to find out the summary mask just do /24 - 3 = /21. if you make it in binary you'll find out the answer too: the interesting octet is 3rd one so let's convert in binary. 8 0000 1000 9 0000 1001 10 0000 1010 11 0000 1011 12 0000 1100 13 0000 1101 14 0000 1110 15 0000 1111 I've bolded the bits in common there are 5 so 16+5=21 which is mask and address is 192.168.8.0

• Question 70:

  If the primary path goes down, what will EIGRP use to reach a destination?

  A. administrative distance
  B. advertised successor
  C. successor
  D. feasible successor
  D. feasible successor

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  The key to this question is the four terminology about DUAL. Enhanced Interior Gateway Routing Protocol (EIGRP) is an enhanced distance-vector protocol based on the diffusing update algorithm (DUAL). It is capable of (conservatively) finding all loop-free paths to any given destination based on route advertisements from neighbors. The neighbor (or neighbors) with the best path to a destination is called the successor. The remaining neighbors with loop-free paths to the destination are called feasible successors. To reduce traffic load on the network, EIGRP maintains neighbor relationships and exchanges routing information only as needed, using a query process to find alternate paths when all loop-free paths to a destination have failed.