Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 31:

  Refer to the exhibit.

  

  ROUTE.com is planning to implement load balancing for traffic between hosts on the 172.16.10.0/24 and 172.16.20./24 networks. You have been asked to review the implementation plan for this project. Which statement about the plan is true?

  A. It is complete as written.
  B. It should include a task to configure EIGRP multipath equal to 2 on R1 and R4.
  C. It should include a task to implement OSPF because it handles unequal cost load balancing most efficiently using variance.
  D. It should include a task that establishes a baseline before and after the configuration has been changed.
  A. It is complete as written.

• Question 32:

  Refer to the exhibit.

  

  What must be configured on router RTA to summarize all routes from area 0 to area 1?

  A. area 0 range 172.16.96.0 255.255.224.0
  B. area 0 range 172.16.96.0 255.255.255.0
  C. area 1 range 172.16.96.0 255.255.224.0
  D. area 1 range 172.16.96.0 255.255.0.0
  E. summary-address 172.16.96.0 255.255.224.0
  F. summary-address 172.16.96.0 0.0.63.255
  A. area 0 range 172.16.96.0 255.255.224.0

  ---

  Recall that summarization is the consolidation of multiple routes into one single, supernet advertisement. See Module 2 for more details on this. Proper summarization requires contiguous, sequential, addressing. 200.10.0.0, 200.10.1.0, 200.10.2.0, and so on are examples of contiguous addressing. OSPF routers can be manually configured to advertise a supernet route, which is different from an LSA summary route. Route summarization directly affects the amount of bandwidth, CPU, and memory resources that are consumed by the OSPF process. With summarization, if a network link fails or flaps, the topology change will not be propagated into the backbone, and other areas by way of the backbone. As discussed in previous modules, route summarization protects routers from needless routing table recalculations. Because the SPF calculation places a significant demand on a router CPU, proper summarization is an important part of OSPF configuration. OSPF supports the following two types of summarization: Interarea route summarization Interarea route summarization is done on ABRs and applies to routes from within each area. It does not apply to external routes injected into OSPF by way of redistribution. To take advantage of summarization, network numbers within areas should be contiguous. External route summarization External route summarization is specific to external routes that are injected into OSPF by way of redistribution. Here again, it is important to ensure that external address ranges that are being summarized are contiguous. Summarization of overlapping ranges from two different routers could cause packets to be sent to the wrong destination. Only ASBRs can summarize external routes. To configure an ABR to summarize routes for a specific area before injecting them into a different area, use the following syntax: Router(config-router)#area area-id range address mask To configure an ASBR to summarize external routes before injecting them into the OSPF domain, use the following syntax: Router(config-router)#summary-address address mask Use the following commands to configure RTA for external router summarization as shown in the Figure. RTA(config)#router ospf 1

  RTA(config-router)#summary-address 200.9.0.0 255.255.0.0 Once configured, RTA will send only a single summary route, 200.9.0.0/16, into the OSPF domain.

  Because RTB sits on the border between Area 0 and Area 1, it should be configured to perform interarea summarization, shown as follows:

  RTB(config)#router ospf 1

  RTB(config-router)#area 1 range 192.168.16.0 255.255.252.0 Notice that the area 1 range command in this example specifies the area containing the range to be summarized before being injected into Area 0.

• Question 33:

  EIGRP performs automatic summarization at network boundaries. What administrative distance is given to these EIGRP summary routes?

  A. 1
  B. 90
  C. 95
  E. 5
  F. 170
  G. 255
  H. None of the other alternatives apply
  E. 5

  ---

  By default, EIGRP summary routes are given an administrative distance value of 5.

• Question 34:

  To configure 6to4 on a dual-stack edge router. Which three of the following are valid in 6to4 Tunneling configuration? (Choose three)

  A. IPv4 Tunnel IP address
  B. Tunnel mode (6to4)
  C. Tunnel Keepalives
  D. IPv4 Tunnel Destination
  E. IPv4 Tunnel Source.
  F. 6to4 IPv6 address (within 2002 /16)
  B. Tunnel mode (6to4)
  E. IPv4 Tunnel Source.
  F. 6to4 IPv6 address (within 2002 /16)

  ---

  Reference: http://packetlife.net/blog/2010/mar/15/6to4-ipv6-tunneling/ (see 6to4 configuration, all three bullets)

• Question 35:

  Which three steps are most helpful in verifying proper route redistribution? (Choose three.)

  A. On the routers not performing the route redistribution, use the show ip route command to see if the redistributed routes show up.
  B. On the ASBR router performing the route redistribution, use the show ip protocol command to verify the redistribution configurations.
  C. On the ASBR router performing the route redistribution, use the show ip route command to verify that the proper routes from each routing protocol are there.
  D. On the routers not performing the route redistribution, use the show ip protocols command to verify the routing information sources.
  E. On the routers not performing the route redistribution, use the debug ip routing command to verify the routing updates from the ASBR.
  A. On the routers not performing the route redistribution, use the show ip route command to see if the redistributed routes show up.
  B. On the ASBR router performing the route redistribution, use the show ip protocol command to verify the redistribution configurations.
  C. On the ASBR router performing the route redistribution, use the show ip route command to verify that the proper routes from each routing protocol are there.

  ---

  In order to verify proper route redistribution, use the "show ip route" command on all routers within the network, as well as the ABSR, to verify that the routes are properly being advertised to all routers. In addition, issuing the "show ip protocol" can be used on the router performing the redistribution to verify that routes are being redistributed into each other.

• Question 36:

  Which of the following must match for two directly connected routers running OSPF to establish a neighbor adjacency? (Select 2 choices.)

  A. area IDs
  B. process IDs
  C. router IDs
  D. hello timers
  A. area IDs
  D. hello timers

  ---

  Hello packets are sent every 10 seconds by default. In order for OSPF routers to establish neighbor adjacencies and exchange routing information successfully, the hello interval needs to match all OSPF routers in the OSPF area. The area number is a number from 0-255, declared at the end of the network command after the wildcard bits. Routers in the same area will exchange routing information or Link State Updates or LSUs

• Question 37:

  Refer to the exhibit.

  

  Router B is performing bidirectional redistribution between EIGRP and OSPF. The network 10.100.1.0/24 should not be reachable from the 10.100.9.0/24 network. However, it needs to be reachable from any network within the EIGRP domain. All other networks should be seen in both domains. Which change to router B would accomplish these goals?

  A. Under the EIGRP process, insert the distribute-list block_net_1 out ospf 1 command.
  B. Under the OSPF process, insert the distribute-list block_net_1 in serial1/0 command.
  C. Under the EIGRP process, insert the distribute-list block_net_1 in serial1/0 command.
  D. Under the OSPF process, insert the distribute-list block_net_1 out eigrp 1 command.
  D. Under the OSPF process, insert the distribute-list block_net_1 out eigrp 1 command.

  ---

  The network 10.100.1.0/24 should not be reachable from network 10.100.9.0/24 -> we need to filter updates from EIGRP to OSPF so that the routing table of router C doesn't have network 10.100.1.0/24 -> we need to filter it under OSPF process and the direction should be out of router B ->.

• Question 38:

  Which two statements about 6to4 tunneling are accurate? (Choose two.)

  A. Prepending a reserved IPv6 code to the hexadecimal representation of 192.168.0.1 facilitates 6to4 tunneling.
  B. Each 6to4 site receives a /48 prefix in a 6to4 tunnel.
  C. 2002::/48 is the address range specifically assigned to 6to4.
  D. Prepending 0x2002 with the IPv4 address creates an IPv6 address that is used in 6to4 tunneling.
  E. 6to4 is a manual tunnel method.
  B. Each 6to4 site receives a /48 prefix in a 6to4 tunnel.
  D. Prepending 0x2002 with the IPv4 address creates an IPv6 address that is used in 6to4 tunneling.

  ---

  Reference: http://msdn.microsoft.com/en-us/library/aa916400.aspx

• Question 39:

  Which EIGRP packet statement is true?

  A. On high-speed links, hello packets are broadcast every 5 seconds for neighbor discovery.
  B. On low-speed links, hello packets are broadcast every 15 seconds for neighbor discovery.
  C. Reply packets are multicast to IP address 224.0.0.10 using RTP.
  D. Update packets route reliable change information only to the affected routers.
  E. Reply packets are used to send routing updates.
  D. Update packets route reliable change information only to the affected routers.

  ---

  Reference: http://docwiki.cisco.com/wiki/Enhanced_Interior_Gateway_Routing_Protocol#EIGRP_Packe t_Types

• Question 40:

  Why should iBGP sessions be fully meshed within a Transit AS?

  A. BGP requires redundant TCP sessions between iBGP peers.
  B. A full mesh allows for optimal routing within the Transit AS.
  C. Routes learned via iBGP are never propagated to other eBGP peers.
  D. Routes learned via iBGP are never propagated to other iBGP peers.
  E. Routes learned via eBGP are never propagated to other iBGP peers.
  D. Routes learned via iBGP are never propagated to other iBGP peers.

  ---

  Any two routers that have formed a TCP connection in order to exchange BGP routing information are called peers or neighbors. It is important to remember that the BGP peers will never become established unless there is IP connectivity between the two peers. BGP does not advertise routes learned by way of IBGP peers to other IBGP peers. If BGP did, BGP routing inside the AS would present a dangerous potential for routing loops. For IBGP routers to learn about all BGP routes inside the AS, they must connect to every other IBGP router in a full IBGP mesh. This full mesh needs to be only logical, not physical. In other words, as long as the IBGP peers can connect to each other using TCP/IP, a logical full mesh can be created even if the routers are not directly connected