Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 77.  A.  Routing loops are the most common problem when you’re using a distance-vector 

routing protocol. Although they can occur with any dynamic routing protocol, distance-

vector protocols are most susceptible due to how they converge routes. RIP is extremely 

compatible with all router implementations, and it is a light protocol; therefore, it is found 

on many different routers. RIP is a very simple protocol to configure compared to other 

dynamic routing protocols. RIP also supports the advertisement of a default route.

 78.  B.  The diffusing update algorithm, or DUAL, is used by EIGRP to calculate the best 

route for the destination network. RIP uses the Bellman-Ford algorithm for calculations 

of routes. OSPF uses the Dijkstra algorithm to calculate the shortest path between two 

networks. BGP uses the best path algorithm that determines the best path between  

two networks.

 79.  B.  Slow convergence of routing tables is a major disadvantage for distance-vector 

protocols like RIP. It could take several announcement cycles before the entire network 

registers a routing change. RIP is an extremely compatible and light protocol; therefore, 

it is found on many different routers. Because RIP is extremely lightweight as a routing 

protocol, it uses very little CPU and RAM. RIP is not best suited for complex networks, 

and therefore, it is very easy to configure.

 80.  A.  The RIP uses the Bellman-Ford routing algorithm to calculate the shortest path based 

on distance. The distance is computed from the shortest number of hops. EIGRP uses the 

DUAL algorithm to calculate the best route for the destination network. OSPF uses the 

Dijkstra algorithm to calculate the shortest path between two networks. BGP uses the best 

path algorithm that determines the best  

path between two networks.

 81.  B.  The use of holddown timers allows the convergence of the network routing tables. This 

is used to hold down changes to the routing table before convergence can happen and a 

routing decision is hastily made by RIP. Although the topology database helps stop routing 

loops, it is not a functional component of distance-vector protocols. There is no such thing 

as anti-flapping ACLs; therefore, it is an incorrect answer. Counting-to-infinity is another 

name for a routing loop, and therefore, it is not a design concept used to stop routing 

loops.

 82.  D.  The Border Gateway Protocol (BGP) is an exterior gateway routing protocol, which 

is used on the exterior of your network. RIPv1 is an internal gateway routing protocol. 

OSPF is an internal gateway routing protocol. EIGRP is a Cisco proprietary internal 

gateway routing protocol.

 83.  C.  Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary interior 

gateway protocol. RIPv1 is an open-source interior gateway protocol. OSPF is also an 

open-source interior gateway protocol. BGP is an open-source interior or exterior gateway 

protocol.

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Chapter 3: IP Connectivity (Domain 3)