Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 11:

  Refer to the exhibit.

  

  Which statement is true?

  A. Router RAR1 will accept only route 10.10.0.0/19 from its BGP neighbor.
  B. Router RAR1 will send only route 10.10.0.0/19 to its BGP neighbor.
  C. Only traffic with a destination from 10.10.0.0/19 will be permitted.
  D. Only traffic going to 10.10.0.0/19 will be permitted.
  A. Router RAR1 will accept only route 10.10.0.0/19 from its BGP neighbor.

  ---

  Wild card mask for /19 is 0.0.31.255. We can see that there is distributed list inbound used to filter routers from BGP neighbor. Distribute list is linked with extend ACL No. 101, which statement permits network 10.10.0.0/19 and denies all other networks, that comes from implicit deny rule at the end of any access list.

• Question 12:

  Observe the diagram.

  

  RTC is the hub router and RTA and RTB are the spokes. There are no virtual circuits between the spoke locations. What is needed to successfully route traffic to the 11.11.11.0/24 network from RTA?

  A. The neighbor 10.10.10.1 next-hop-self command on RTA.
  B. The neighbor 10.10.10.1 next-hop-self command on RTB.
  C. The neighbor 10.10.10.1 next-hop-self command on RTC.
  D. Nothing is required. This is the default behavior on this topology.
  C. The neighbor 10.10.10.1 next-hop-self command on RTC.

  ---

  The following example illustrates the issue: BGP Next Hop (NBMA) If the common media as you see in the shaded area above is a frame relay or any NBMA cloud then the exact behavior will occur as if we were connected via Ethernet. RTC will advertise 180.20.0.0 to RTA with a next hop of 170.10.20.3. The problem is that RTA does not have a direct PVC to RTD, and cannot reach the next hop. In this case routing will fail. In order to remedy this situation a command called next-hop-self is created. The next-hop-self Command Because of certain situations with the next hop as we saw in the previous example, a command called next-hop-self is created. The syntax is: neighbor {ip-address|peer-group-name} next-hop-self The next-hop-self command allows us to force BGP to use a specified IP address as the next hop rather than letting the protocol choose the next hop. In the previous example, the following configuration solves our problem: RTC# router bgp 300 neighbor 170.10.20.1 remote-as 100 neighbor 170.10.20.1 next-hop-self RTC advertises 180.20.0.0 with a next hop = 170.10.20.2 Reference: http://www.cisco.com/warp/public/459/bgp-toc.html#bgpnexthop

  

• Question 13:

  Refer to the exhibit.

  

  EIGRP has been configured on router D. Router C is performing mutual redistribution between EIGRP and OSPF. While verifying that the redistribution is functioning properly, you discover that while router C has all of the EIGRP routes in its routing table, router A does not have any routes from the EIGRP domain. What on router C may be the cause of the problem?

  A. The no auto-summary command needs to be added under router eigrp 1.
  B. The subnets keyword was not included in the redistribute command under router ospf 1.
  C. The metric specified for the redistributed EIGRP routes is too large; making the EIGRP routes unreachable by router A.
  D. The default-information originate command needs to be added under router ospf 1.
  E. The administrative distance of either OSPF or EIGRP must be changed so that EIGRP has a higher administrative distance than OSPF.
  B. The subnets keyword was not included in the redistribute command under router ospf 1.

  ---

  If we don't use the "subnets" keyword when redistributing routes learned from another routing process into OSPF, only classful routes will be redistributed. This is an important thing to remember when redistributing into OSPF.

• Question 14:

  Which BGP path attribute is Cisco proprietary?

  A. weight
  B. MED
  C. local preference
  D. origin
  E. next-hop
  F. AS-path
  A. weight

  ---

  The weight attribute is a Cisco proprietary technology. This attribute is local to a router and is not advertised to neighboring routers. If the router learns about more than one route to the same destination, the route with the highest weight will be preferred and will be installed in the routing table. By default, the value of weight is 0 and the range is from 0 to 65535.

  The route with the highest weight will be installed in the IP routing table.

• Question 15:

  When an IPv6 enabled host boots, it sends a router solicitation (RS) message. An IPv6 router responds with a router advertisement (RA). Which two items are contained in the RA? (Choose two.)

  A. IPv6 address for the host
  B. lifetime of the prefix
  C. prefixes for the link
  D. keepalive timers
  E. request for the local host IP address
  F. any route advertisements it has received
  B. lifetime of the prefix
  C. prefixes for the link

  ---

  In IP Version 6, Router Advertisements have the following attributes: Routers advertise periodically Max. time between advertisements can be in the range from 4 and 1800 seconds Advertisement contains one or more prefixes The advertisement has a lifetime (= 0 if not a default router) Prefixes have a lifetime Preferred lifetime Valid lifetime Specifies if stateful or stateless autoconfiguration is to be used ?Plays a key role in site renumbering

• Question 16:

  Under which circumstance will a branch ISR router contain interface vlan configurations?

  A. performing inter-VLAN routing
  B. performing 802.1Q trunking
  C. performing ISL trunking
  D. Ethernet Switch Module installed
  E. ADSL WIC installed
  F. running Call Manager Express
  D. Ethernet Switch Module installed

  ---

  In smaller offices, a single ISR may be used for a both remote connectivity and inter-VLAN routing. In that case, know that an Ethernet Switch Module would be required for the ISR router

• Question 17:

  You are developing a verification plan for an upcoming OSPF implementation. Part of this plan is to verify the status of type 3 LSAs within the network. Which routers should you verify first to ensure that the configurations are correct for generating type 3 LSAs?

  A. Internal routers within the backbone area (area 0)
  B. Internal routers within the NSSAs
  C. Internal routers within the stubby areas
  D. ASBRs
  E. ABRs
  F. DRs and BDRs
  E. ABRs

  ---

  Type 3 LSA (Summary LSA) is advertised by the ABR of originating area to advertise network from other areas so we should check the ABRs first.

• Question 18:

  Refer to the exhibit.

  

  Network administrators have set up a hub and spoke topology with redundant connections using EIGRP. However, they are concerned that a network outage between Router R1 and Router R2 will cause traffic from the 10.1.1.x network to the 10.1.2.x network to traverse the remote office links and overwhelm them. What command should be used to configure the spoke routers as EIGRP stub routers that will not advertise connected networks, static routes, or summary addresses?

  A. eigrp stub
  B. eigrp stub receive-only
  C. eigrp stub connected static
  D. no eigrp stub connected static
  E. No additional command is needed beyond a default EIGRP configuration.
  B. eigrp stub receive-only

  ---

  A router that is configured as a stub with the eigrp stub command shares connected and summary routing information with all neighbor routers by default. Four optional keywords can be used with the eigrp stub command to modify this behavior:

  

  receive-only connected

  static

  summary

  This section provides configuration examples for all forms of the eigrp stub command. The eigrp stub command can be modified with several options, and these options can be used in any combination except for the receive-only keyword. The

  receive-only keyword will restrict the router from sharing any of its routes with any other router in that EIGRP autonomous system, and the receive-only keyword will not permit any other option to be specified because it prevents any type of

  route from being sent. The three other optional keywords (connected, static, and summary) can be used in any combination but cannot be used with the receive-only keyword. If any of these three keywords is used individually with the eigrp

  stub command, connected and summary routes will not be sent automatically.

  The connected keyword will permit the EIGRP Stub Routing feature to send connected routes. If the connected routes are not covered by a network statement, it may be necessary to redistribute connected routes with the redistribute

  connected command under the EIGRP process. This option is enabled by default.

  The static keyword will permit the EIGRP Stub Routing feature to send static routes. Without the configuration of this option, EIGRP will not send any static routes, including internal static routes that normally would be automatically

  redistributed. It will still be necessary to redistribute static routes with the redistribute static command.

  The summary keyword will permit the EIGRP Stub Routing feature to send summary routes. Summary routes can be created manually with the summary address command or automatically at a major network border router with the auto-

  summary command enabled.

  This option is enabled by default.

  In the following example, the eigrp stub command is used to configure the router as a stub that advertises connected and summary routes:

  router eigrp 1

  network 10.0.0.0

  eigrp stub

  In the following example, the eigrp stub command is issued with the connected and static keywords to configure the router as a stub that advertises connected and static routes (sending summary routes will not be permitted):

  router eigrp 1

  network 10.0.0.0

  eigrp stub connected static

  In the following example, the eigrp stub command is issued with the receive-only keyword to configure the router as a receive-only neighbor (Connected, summary, and static routes will not be sent):

  router eigrp 1

  network 10.0.0.0 eigrp

  eigrp stub receive-only

  Reference:

  http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00 80087026.html

• Question 19:

  Refer to the exhibit.

  

  ROUTE Enterprises has many stub networks in their enterprise network, such as router B and its associated network. EIGRP is to be implemented on router A so that neither the prefix for the S/0/0/0 interface nor the prefixes from router B appear in the routing tables for the router in the enterprise network. Which action will accomplish this goal?

  A. Declare router B a stub router using the eigrp stub command.
  B. Use the passive-interface command for interface Serial0/0/0.
  C. Use a mask with the network command to exclude interface Serial0/0/0.
  D. Implement a distribute list to exclude the link prefix from the routing updates.
  C. Use a mask with the network command to exclude interface Serial0/0/0.

  ---

  If we declare router B a stub router then the routers in Enterprise Network still learn about the network for S0/0/0 interface and the network behind router B.

  If we use the passive-interface command on s0/0/0 interface then router A and B can not become neighbors because they don't exchange hello messages -> A can not send traffic to the network behind B . Theoretically, we can use a distribute list to exclude both the link prefix and the prefix from router B but it is not efficient because:

  + We have many stub networks so we will need a "long" distribute list. + We declare networks in stub routers (like router B) while filter them out at router A -> it is a waste.

  Not totally sure about answer C because if we "use a mask with the network command to exclude interface Serial0/0/0 then router A and B can not become neighbors and the situation is same as answer B. But from many discussions about this question, maybe C is the best answer.

• Question 20:

  What two features are benefits of using GRE tunnels with IPsec over using an IPsec tunnel alone in building-to-building site-to-site VPNs? (Choose two.)

  A. allows dynamic routing securely over the tunnel
  B. IKE keepalives are unidirectional and sent every ten seconds
  C. reduces IPsec headers overhead since tunnel mode is used
  D. supports non-IP traffic over the tunnel
  E. uses Virtual Tunnel Interface (VTI) to simplify the IPsec VPN configuration
  A. allows dynamic routing securely over the tunnel
  D. supports non-IP traffic over the tunnel

  ---

  Reference:

  http://ptgmedia.pearsoncmg.com/images/9781587201509/samplechapter/158720150X_CH14 .pdf (page 332)