Ccna certification Practice Tests

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 161.  D.  OSPF employs link-state advertisement (LSA) flooding and triggered updates. When 

these occur, every participating router will recalculate its routing tables. Link-state routing 

protocols do not use hop count as a metric. Link-state routing protocols support CIDR 

and VLSM, but all other routing protocols also support CIDR and VLSM; therefore, it is 

not an advantage. OSPF requires a rather large amount of CPU and RAM to calculate and 

retain databases.

 162.  C.  Link-state protocols such as OSPF are best suited for large hierarchical networks 

such as global networks, since they can separate out the participating routers with areas 

and border area routers. Extremely small networks do not warrant the planning and 

maintenance of OSPF and are best suited for static routing. Networks with routers that 

have a limited amount of RAM and CPU are best suited for static routing. OSPF requires 

a network admin with the knowledge of OSPF so it is properly configured.

 163.  B.  Open Shortest Path First (OSPF) is an interior gateway protocol and a nonproprietary 

standard. Exterior gateway protocol (EGP) is a class of protocols used externally on an 

organization’s network. Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco 

proprietary protocol. Border Gateway Protocol (BGP) is an EGP.

 164.  B.  Although you have different administrative units, all of the administrative units are 

in the same company. In this situation, it is recommended to use an interior gateway 

protocol that can segment each administrative unit. OSPF will perform this requirement 

with the use of area IDs. Border Gateway Protocol (BGP) is an EGP used to work with 

different autonomous routing organizations. RIPv2 does not have the ability to segment 

administrative units. Exterior gateway protocol (EGP) is a class of protocols used 

externally on the organization’s network.

 165.  A.  Area 0 must be present in an OSPF network. It is the backbone area and all other areas 

must connect to it. All other answers are incorrect.

 166.  C.  Router A is on the boundary of the autonomous system, which OSPF manages; 

therefore, it is an autonomous system boundary router, or ASBR. Area border routers 

(ABRs) are routers that sit between one or more OSPF areas. Autonomous system routers 

(ASRs) are routers that sit between one or more autonomous systems. Area backup routers 

is not a type of router for OSPF.

 167.  B.  OSPF uses 224.0.0.5 for neighbor discovery via link-state advertisements (LSAs). 

Routing Information Protocol version 2 (RIPv2) uses 224.0.0.9 for routing updates. OSPF 

uses 224.0.0.6 for DRs and backup designated routers (BDR). EIGRP uses 224.0.0.7 for 

neighboring routers.

 168.  A.  Routers C, D, and E are called area border routers, or ABRs. They border both the 

backbone area and areas 1, 2, and 3, respectively. Autonomous system routers (ASRs) are 

routers that sit between one or more autonomous systems. Router A is on the boundary 

of the autonomous system, which OSPF manages; therefore, it is an autonomous system 

boundary router, or ASBR. Area backup routers (ABRs) are routers that will take over for 

a router covering a routing area.

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