Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 181:

  RouterA# ~~~~~ ! router ospf 1 log-adjacency-changes network 10.0.0.0 0.255.255.255 area 1 network 172.16.1.0 0.0.0.255 area 1

  !

  ~~~~~

  RouterB#

  ~~~~~

  router ospf 1

  log-adjacency-changes

  network 10.0.0.0 0.255.255.255 area 2

  network 172.16.2.0 0.0.0.255 area 2

  !

  ~~~~~

  RouterC#

  ~~~~~

  !

  router ospf 1

  log-adjacency-changes

  network 10.0.0.0 0.255.255.255 area 0

  !

  ~~~~~

  Refer to the exhibits. You are verifying your OSPF implementation, and it does not seem to be functioning properly. What can you conclude from the exhibit and the show running- configuration command output?

  

  A. The OSPF areas are not configured correctly.
  B. The wildcard masks for the 10.x.x.x networks are incorrect.
  C. The 172.16.x.x networks need to be connected to area 0 using virtual links.
  D. The 172.16.x.x networks are discontiguous. OSPF is automatically summarizing them to 172.16.0.0/16 and data is being "black holed."
  E. There is not enough information to make a determination.
  A. The OSPF areas are not configured correctly.

  ---

  The E0/0 and E0/1 interfaces of router C belong to area 0 while E0/0 of router A belongs to area 1; E0/0 of router B belongs to area 2 -> it is not correct. Both E0/0 interfaces of router A and B should be in area 0 -> A is not correct.

• Question 182:

  Refer to the exhibit.

  

  The routing protocols EIGRP and OSPF have been configured as indicated in the exhibit. Given the partial configuration of router R2, which network will be present in the routing table of R4?

  A. Network A
  B. Network B
  C. Network A and Network B
  D. neither Network A nor Network B
  B. Network B

  ---

  In this exhibit the OSPF domain is redistributed into the EIGRP 100 domain so Network B will present into Router R-4. However, the Network A network will not be seen on router R-4 (The bottom router which is improperly labeled Network B) because EIGRP 50 was not redistributed into EIGRP 100.

• Question 183:

  Refer to the exhibit.

  

  OSPF has been configured on all routers in the network. However, router R1 does not receive a default route to router R2 as intended. Which configuration change would ensure that R1 would receive a default route from R2?

  A. Add the area 1 stub command on routers R1.
  B. Add the always keyword to the default-information originate configuration command on router R2.
  C. Remove the default information originate configuration command from router R2 and place it on router R1.
  D. Add the ip route 5.0.0.0 255.255.255.0 0.0.0.0 command to router R2.
  B. Add the always keyword to the default-information originate configuration command on router R2.

  ---

  The point of this question is about advertise a default route into an ospf area. There are two ways to advertise a default route into an ospf area. The first is to advertise 0.0.0.0 into the OSPF domain, provided the advertising router already has a default route. The second is to advertise 0.0.0.0 regardless of whether the advertising router already has a default route. The second method can be accomplished by adding the keyword always to the default- information originate command. In this example, the "always" keyword would be required in order to propagate this default route.

• Question 184:

  Which condition must be satisfied before an EIGRP neighbor can be considered a feasible successor?

  A. The neighbor's advertised distance must be less than or equal to the feasible distance of the current successor.
  B. The neighbor's advertised distance must be less than the feasible distance of the current successor.
  C. The neighbor's advertised distance must be greater than the feasible distance of the current successor.
  D. The neighbor's advertised distance must be equal to the feasible distance of the current successor.
  E. The neighbor's advertised distance must be greater than or equal to the feasible distance of the current successor.
  B. The neighbor's advertised distance must be less than the feasible distance of the current successor.

  ---

  The feasible successor route is a route which has a higher metric than the successor route to reach a subnet but meets the feasibility condition and can be used in the event that the successor route goes down. This route does NOT get installed in the routing table but is kept in the topology table. The feasibility condition states that the AD from a neighbor must be less than the metric of the successor route (the feasible distance [FD]) because routing through a feasible successor when the AD > FD may cause a routing loop.

• Question 185:

  Refer to the exhibit.

  

  Routers R1 and R2 are IPv6 BGP peers that have been configured to support a neighbor relationship over an IPv4 internet work. Which three neighbor IP addresses are valid choices to use in the highlighted section of the exhibit? (Choose three.)

  A. ::0A43:0002
  B. 0A43:0002::
  C. ::10.67.0.2
  D. 10.67.0.2::
  E. 0:0:0:0:0:0:10.67.0.2
  F. 10.67.0.2:0:0:0:0:0:0
  A. ::0A43:0002
  C. ::10.67.0.2
  E. 0:0:0:0:0:0:10.67.0.2

  ---

  The automatic tunneling mechanism uses a special type of IPv6 address, termed an "IPv4- compatible" address. An IPv4-compatible address is identified by an all-zeros 96-bit prefix, and holds an IPv4 address in the low-order 32-bits. IPv4compatible addresses are structured as follows:

  

  Therefore, an IPv4 address of 10.67.0.2 will be written as ::10.67.0.2 or 0:0:0:0:0:0:10.67.0.2 or ::0A43:0002 (with 10[decimal] = 0A[hexa] ; 67[decimal] = 43[hexa] ; 0[hexa] = 0[decimal] ; 2[hexa] = 2[decimal])

• Question 186:

  After DUAL calculations, a router has identified a successor route, but no routes have qualified as a feasible successor. In the event that the current successor goes down, what process will EIGRP use in the selection of a new successor?

  A. EIGRP will find the interface with the lowest MAC address
  B. The route will transition to the active state
  C. The route will transition to the passive state
  D. EIGRP will automatically use the route with the lowest feasible distance(FD)
  E. EIGRP will automatically use the route with the lowest advertised distance(AD)
  B. The route will transition to the active state

  ---

  When a route (current successor) goes down, the router first checks its topology table for a feasible successor but it can't find one. So it goes active on the that route to find a new successor by sending queries out to its neighbors requesting a path to the lost route.

• Question 187:

  A policy needs to be implemented on Router B so that any traffic sourced from 172.16.10.0/24 will be forwarded to Router C.

  

  Which configuration on Router B will achieve the desired effect?

  A. access-list 1 permit 172.16.10.0 0.0.0.255 ! interface s0 ip policy route-map policy ! route-map policy permit 10 match ip address 1 set ip next-hop 172.16.12.3
  B. access-list 1 permit 172.16.10.0 0.0.0.255 ! interface e0 ip policy route-map policy ! route-map policy permit 10 match ip address 1 set ip next-hop 172.16.12.2
  C. access-list 1 permit 172.16.10.0 0.0.0.255 ! interface e0 ip policy route-map policy ! route-map policy permit 10 match ip address 1 set ip next-hop 172.16.14.4
  D. access-list 1 deny 172.16.10.0 0.0.0.255 ! interface s0 ip policy route-map policy ! route-map policy permit 10 match ip address 1 set ip next-hop 172.16.12.2
  A. access-list 1 permit 172.16.10.0 0.0.0.255 ! interface s0 ip policy route-map policy ! route-map policy permit 10 match ip address 1 set ip next-hop 172.16.12.3

  ---

  The "next-hop" IP address should be the E1 interface of router C (172.16.12.3).

• Question 188:

  Refer to the exhibit.

  

  Which interoperability technique implemented on the router would allow Host-1 to communicate with Host-2?

  A. Dual Stack
  B. NAT-PT
  C. 6to4 tunnel
  D. GRE tunnel
  E. ISATAP tunnel
  B. NAT-PT

  ---

  Reference:

  http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps6969/ps1835/prod_white_pap er09186a008011ff51.html

• Question 189:

  Which three statements are true about EIGRP operation? (Choose three.)

  A. When summarization is configured, the router will also create a route to null 0.
  B. The summary route remains in the route table, even if there are no more specific routes to the network.
  C. Summarization is configured on a per-interface level.
  D. The maximum metric for the specific routes is used as the metric for the summary route.
  E. Automatic summarization across major network boundaries is enabled by default.
  A. When summarization is configured, the router will also create a route to null 0.
  C. Summarization is configured on a per-interface level.
  E. Automatic summarization across major network boundaries is enabled by default.

  ---

  Reference: http://astorinonetworks.com/2011/07/20/summary-routes-to-null0-the-protocols- that-love-them/

• Question 190:

  Refer to the exhibit.

  

  Router RT-1 and router RT-2 both advertise network 131.25.0.0/16 to router RT-3 via internal BGP. What is the reason that router RT-3 chose router RT-1 as its best path to network 131.25.0.0/16.

  A. It advertises the best AS-path.
  B. It advertises the best origin code.
  C. It advertises the best MED.
  D. It advertises the best local preference.
  E. It has a better router ID.
  F. It advertises a lower autonomous system.
  E. It has a better router ID.

  ---

  After BGP receives updates about different destinations from different autonomous systems, it chooses the best path to reach a specific destination. The following process summarizes how BGP chooses the best route on a Cisco router.

  Prefer the route with the highest weight. (The weight attribute is proprietary to Cisco and is local to the router only.)

  If multiple routes have the same weight, prefer the route with the highest local preference value. (The local preference is used within an autonomous system.) If multiple routes have the same local preference, prefer the route that the local

  router originated. A locally originated route has a next hop of 0.0.0.0 in the BGP table. If none of the routes were locally originated, prefer the route with the shortest autonomous system path. If the autonomous system path length is the same,

  prefer the lowest origin code (IGP < EGP < incomplete). If all origin codes are the same, prefer the path with the lowest MED. (The MED is exchanged between autonomous systems.) The MED comparison is made only if the neighboring

  autonomous system is the same for all routes considered, unless the bgp always-compare-med command is enabled If the routes have the same MED, prefer external paths to internal paths. If synchronization is disabled and only internal

  paths remain, prefer the path through the closest IGP neighbor, which means that the router prefers the shortest internal path within the autonomous system to reach the destination (the shortest path to the BGP next hop).

  For EBGP paths, select the oldest route to minimize the effect of routes going up and down (flapping). Prefer the route with the lowest neighbor BGP router ID value. If the BGP router IDs are the same, prefer the router with the lowest

  neighbor IP address. In this case, since everything else is equal the router ID will be used, and the specific router ID that is chosen is 165.1.1.1 (lowest one), which is RT-3.