Which routing protocol is designed to use areas to scale large hierarchical networks?

Last Updated on November 10, 2022 by

1. Which dynamic routing protocol was developed as an exterior gateway protocol to interconnect different Internet providers?

   •  BGP
   •  EIGRP
   •  OSPF
   •  RIP

   Explanation:

   BGP is a protocol developed to interconnect different levels of ISPs as well as ISPs and some of their larger private clients.

2. In the context of routing protocols, what is a definition for time to convergence?

   •  the amount of time a network administrator needs to configure a routing protocol in a small- to medium-sized network
   •  the capability to transport data, video, and voice over the same media
   •  a measure of protocol configuration complexity
   •  the amount of time for the routing tables to achieve a consistent state after a topology change

   Explanation:

   Time to convergence defines how quickly the routers in the network topology share routing information and reach a state of consistent knowledge.

3. An OSPF enabled router is processing learned routes to select best paths to reach a destination network. What is the OSPF algorithm evaluating as the metric?

   •  The amount of packet delivery time and slowest bandwidth.
   •  The number of hops along the routing path.
   •  The amount of traffic and probability of failure of links.
   •  The cumulative bandwidth that is used along the routing path.

   Explanation:

   The OSPF routing protocol uses the cumulative bandwidth as the metric for route computations.​

4. What is the difference between interior and exterior routing protocols?

   •  Exterior routing protocols are used only by large ISPs. Interior routing protocols are used by small ISPs.
   •  Interior routing protocols are used to route on the Internet. Exterior routing protocols are used inside organizations.
   •  Exterior routing protocols are used to administer a single autonomous system. Interior routing protocols are used to administer several domains.
   •  Interior routing protocols are used to communicate within a single autonomous system. Exterior routing protocols are used to communicate between multiple autonomous systems.

   Explanation:

   Interior gateway protocols (IGPs) are used for routing within an organization having a common administration or autonomous system (AS). Exterior gateway protocols (EGPs) are used by service providers and sometimes by large companies.

5. What are two purposes of dynamic routing protocols? (Choose two.)

   •  provide a default route to network hosts
   •  discover remote networks
   •  provide network security
   •  reduce network traffic
   •  select best path to destination networks

   Explanation:

   The purpose of dynamic routing protocols include the following:

   • Discover remote networks
   • Maintain up-to-date routing information
   • Choose the best path to a destination network
   • Find a new best path if the current path is not available

6. Which routing protocol is designed to use areas to scale large hierarchical networks?

   •  RIP
   •  EIGRP
   •  OSPF
   •  BGP

   Explanation:

   OSPF works best for a large hierarchical network, because OSPF supports a multiarea design, which provides a much better scaling capability compared with EIGRP

7. Which two routing protocols are classified as distance vector routing protocols? (Choose two.)

   •  OSPF
   •  EIGRP
   •  BGP
   •  IS-IS
   •  RIP

   Explanation:

   RIP and EIGRP are classified as distance vector routing protocols, OSPF and IS-IS are classified as link-state, and BGP is classified as a path-vector routing protocol.

8. Refer to the exhibit. A network administrator has configured RIPv2 in the given topology. Which path would a packet take to get from the LAN that is connected to R1 to the LAN that is connected to R7?

   

   CCNA3 v6.0 Chapter 5 Exam 002

   •  R1–R3–R4–R5–R6–R7
   •  R1–R3–R2–R6–R7
   •  R1–R3–R2–R6–R7
   •  R1–R2–R6–R7

   Explanation:

   RIP utilizes hop count to calculate the best path from source to destination.

9. Which routing protocol sends a routing update to neighboring routers every 30 seconds?

   •  RIP
   •  EIGRP
   •  OSPF
   •  BGP

   Explanation:

   Regardless of topology changes, RIP sends a periodic update to all neighboring routers every 30 seconds.

10. After a network topology change occurs, which distance vector routing protocol can send an update message directly to a single neighboring router without unnecessarily notifying other routers?

    •  IS-IS
    •  RIPv2
    •  EIGRP
    •  OSPF
    •  RIPv1

    Explanation:

    RIPv2 and EIGRP support updating neighboring routers via the use of multicasting. EIGRP is the only distance vector protocol that can support updating a specific neighbor by using unicast. OSPF and ISIS are link state protocols.

11. Which feature provides secure routing updates between RIPv2 neighbors?

    •  unicast updates
    •  routing protocol authentication
    •  keepalive messages
    •  adjacency table

    Explanation:

    The RIPv2 routing protocol supports routing protocol authentication to secure routing table updates between neighbors.

12. What is maintained within an EIGRP topology table?

    •  all routes received from neighbors
    •  the hop count to all networks
    •  the area ID of all neighbors
    •  the state of all links on the network

    Explanation:

    The EIGRP topology table maintains all the routes received from neighbors, not just the best paths. DUAL can use backup routes from the topology table to provide instantaneous route failover in the EIGRP routing table.

13. A network administrator is researching routing protocols for implementation in a critical network infrastructure. Which protocol uses the DUAL algorithm to provide almost instantaneous convergence during a route failover?

    •  EIGRP
    •  RIP
    •  OSPF
    •  BGP

    Explanation:

    EIGRP is commonly the fastest IGP to converge because it maintains alternate routes. A switchover to an alternate route is immediate and does not involve interaction with other routers.

14. Refer to the exhibit. OSPF is used in the network. Which path will be chosen by OSPF to send data packets from Net A to Net B?

    

    CCNA3 v6.0 Chapter 5 Exam 001

    •  R1, R2, R5, R7
    •  R1, R3, R5, R7
    •  R1, R3, R6, R7
    •  R1, R4, R6, R7
    •  R1, R3, R5, R6, R7

    Explanation:

    OSPF uses the shortest path first algorithm to select the best path to forward packets. Each path is labeled with a value for cost and this algorithm accumulates costs along each path, from source to destination. The path chosen from Net A to Net B is R1-R3-R5-R7, that is equal to 5+7+14+2=28, the shortest cost.

15. What are two features of the OSPF routing protocol? (Choose two.)

    •  automatically summarizes networks at the classful boundaries
    •  has an administrative distance of 100
    •  calculates its metric using bandwidth
    •  uses Dijkstra’s algorithm to build the SPF tree
    •  used primarily as an EGP

    Explanation:

    Characteristics of OSPF include the following:

    • Interior gateway protocol
    • Link-state
    • Classless
    • Cost metric based on bandwidth
    • Dijkstra algorithm
    • Builds topological map
    • Event-driven updates
    • Hierarchical design
    • Requires additional memory, CPU processing, and more initial bandwidth than other protocols

16. Which two protocols are link-state routing protocols? (Choose two.)

    •  RIP
    •  OSPF
    •  EIGRP
    •  BGP
    •  IS-IS
    •  IGP

    Explanation:

    OSPF and IS-IS are link-state protocols. EIGRP and RIP are distance vector protocols.

17. Which routing protocol uses link-state information to build a map of the topology for computing the best path to each destination network?

    •  OSPF
    •  EIGRP
    •  RIP
    •  RIPng

    Explanation:

    OSPF is a link-state routing protocol and as such it uses a link-state database to construct a topology map of the network to calculate the best path to destination networks. RIP, RIPng, and EIGRP are distance vector routing protocols.

18. Which two requirements are necessary before a router configured with a link-state routing protocol can build and send its link-state packets? (Choose two.)

    •  The router has determined the costs associated with its active links.
    •  The router has built its link-state database.
    •  The routing table has been refreshed.
    •  The router has established its adjacencies.
    •  The router has constructed an SPF tree.

    Explanation:

    Once a router has established its adjacencies, it can build its link-state packets (LSPs) that contain the link-state information, including the link cost. A router can only build a link-state after it has received link-state packets from adjacent routers. It then constructs its SPF tree from the least cost routes to remote networks which are used to populate its routing table.

19. What happens when two link-state routers stop receiving hello packets from neighbors?

    •  They continue to operate as normal and are able to exchange packets.
    •  They consider the neighbor to be unreachable and the adjacency is broken.
    •  They create a default route to the adjacent router.
    •  They will flood their database tables to each other.

    Explanation:

    Hello packets serve a keepalive function to monitor the state of an adjacent router.

20. Which two events will trigger the sending of a link-state packet by a link-state routing protocol? (Choose two.)

    •  the router update timer expiring
    •  a link to a neighbor router has become congested
    •  a change in the topology
    •  the initial startup of the routing protocol process
    •  the requirement to periodically flood link-state packets to all neighbors

    Explanation:

    An LSP (link-state packet) is only sent during initial startup of the routing protocol process on a router; and whenever there is a change in the topology, including a link going down or coming up, or a neighbor adjacency being established or broken. Data traffic congestion does not directly influence routing protocol behavior. LSPs are not flooded periodically, and update timers are not relevant to LSPs.

21. What is the first step taken by a newly configured OSPF router in the process of reaching a state of convergence?

    •  It builds the topological database.
    •  It floods LSP packets to neighboring routers.
    •  It learns about directly connected links in an active state.
    •  It exchanges hello messages with a neighboring router.

    Explanation:

    Before OSPF can form a neighbor adjacency and start the Hello protocol, it detects which interfaces are in an up and active state.

22. Which two components of an LSP enable an OSPF router to determine if the LSP that is received contains newer information than what is in the current OSPF router link-state database? (Choose two.)

    •  query
    •  sequence numbers
    •  acknowledgements
    •  hellos
    •  aging information

    Explanation:

    Information such as sequence numbers and aging information is included in an LSP to help manage the flooding process. This information can assist a router in determining if it has already received the LSP from another router or if the LSP has newer information than what is already contained in the link-state database.

23. Which statement is an incorrect description of the OSPF protocol?

    •  Multiarea OSPF helps reduce the size of the link-state database.
    •  OSPF builds a topological map of the network.
    •  When compared with distance vector routing protocols, OSPF utilizes less memory and less CPU processing power.
    •  OSPF has fast convergence.

    Explanation:

    Link-state protocols require more memory to create and maintain the link-state database.

24. What is a disadvantage of deploying OSPF in a large single area routing environment?

    •  OSPF uses multicast updates.
    •  OSPF uses excessive LSP flooding.
    •  OSPF uses a topology database of alternate routes.
    •  OSPF uses a metric of bandwidth and delay.

    Explanation:

    Link-state protocols have the following disadvantages:

    • Memory Requirements – Creating and maintaining the link-state database and SPF tree.
    • Processing Requirements – The SPF algorithm requires more CPU time than distance vector algorithms because link-state protocols build a complete map of the topology.
    • Bandwidth Requirements – Link-state packet flooding can adversely affect the available bandwidth on a network.

25. Match the features of link-state routing protocols to their advantages and disadvantages. (Not all options are used.)

    
    CCNA3 v6.0 Chapter 5 Exam 01

    Explanation:

    Link-state routing protocols have their advantages and disadvantagea. The advantages are that each router builds a topological map; there is fast convergence; and the LSPs are sent only when there is a change in topology. The disadvantages are the requirements of router and bandwidth resources because of the complexity of the link-state routing protocols.