Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 154.  D.  The command 

default-information originate will advertise the default route 

to all other RIPv2 routers. The command 

network 0.0.0.0 is incorrect. The command 

default-route advertise is incorrect. The command network 0.0.0.0 default is 

incorrect.

 155.  C.  The correct command to implement a default route for routing is 

ip route 0.0.0.0 

0.0.0.0 192.168.2.6. The command ip default-network 192.168.2.6 is incorrect. 

The command 

ip route default-gateway 192.168.2.6 is incorrect. The command ip 

route 0.0.0.0 255.255.255.255 192.168.2.6 is incorrect.

 156.  D.  You can conclude the ping packet was routed through 3 routers, because the default 

TTL is 255. If the packet started with a TTL of 255 and a TTL of 252 was reported, 

3 routers routed the ping packet (255 – 252 = 3). Time has nothing to do with TTL; 

therefore, the time and delay are not reported in the resultant TTL. The TTL decrements 

by one as the packet is routed by each router to its destination. Therefore, the answer of 

252 routers is invalid.

 157.  D.  The command 

show ip route rip will display only the route entries for the RIP 

protocol that exist in the route table. Always remember that the Cisco commands should 

be from left to right, least specific to most specific; therefore, 

show ip pertains to the IPv4 

stack, 

route pertains to the route table, and rip specifies only those entries in the table. 

The command 

show ip rip is incorrect. The command show ip route is incorrect. The 

command 

show ip rip route is incorrect.

 158.  B.  Open Shortest Path First (OSPF) is a true link-state protocol. Link-state protocols 

keep track of the state of the links as well as the bandwidth the links report. Routing 

Information Protocol (RIP) is a distance-vector routing protocol. Enhanced Interior 

Gateway Routing Protocol (EIGRP) is a hybrid routing protocol. Border Gateway Protocol 

is a path-vector routing protocol.

 159.  C.  The Dijkstra algorithm is used by OSPF to calculate the shortest path based on a cost 

calculation of the bandwidth of the link vs. distance vector, which is based on hop count. 

RIP uses the Bellman-Ford algorithm to calculate distance. EIGRP uses the diffusing 

update algorithm to calculate a best route. BGP uses the best path algorithm to determine 

the best path for a packet.

 160.  A.  Link-state protocols such as OSPF require all routers to maintain their own topology 

database of the network. This topology database is why routing loops are less likely to 

occur. Distance-vector protocols don’t really have a topology of the network and thus 

suffer from routing loops. Each router is responsible for maintaining its own topology 

database and therefore does not share its topology. A router will only create a neighbor 

database for the neighboring routers, and OSPF will not track the state of all other routers 

as well. Link-state protocols can use multiple routes to the same destination, but by 

default, only one successive route will be entered in the route table.

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Chapter 3: IP Connectivity (Domain 3)