CCNA Sample Questions

640-801

41. You work as network administrator at Brain dump. Your trainee is configuring a router with both physical and logical interfaces. He asks you what factor determines the OSPF router ID. What should you tell him?
    1. The lowest IP address of any interface.
    2. The highest IP address of any interface.
    3. The highest IP address of any logical interface.
    4. The middle IP address of any logical interface.
    5. The lowest IP address of any physical interface.
    6. The highest IP address of any physical interface.
    7. The lowest IP address of any logical interface.

    Answer :F

    Explanation: The OSPF topology database includes information about routers and the subnets, or links, to which they are attached. To identify the routers in the neighbor table’s topology database, OSPF uses a router ID (RID) for each router. A router’s OSPF RID is that router’s highest IP address on a physical interface when OSPF starts running.

    Note: The OSPF router ID is a 32-bit IP address selected at the beginning of the OSPF process. Thehighest IP address configured on the router is the router ID. If a loopback address is configured, then it is the router ID. In case of multiple loopback addresses, the highest loopback address is the router ID. Once the router ID is elected it doesn't change unless the IP address is removed or OSPF restarts.

42. Which of the following routes will be used to forward data in a situation where a routing table contains static, RIP, and IGRP routes destined to the same network with each set to its default administrative distance?
    1. The IGRP route
    2. The static route
    3. The RIP route
    4. All three will load balance.

    Answer :B

    Explanation:To decide which route to use, IOS uses a concept called Administrative Distance. Administrative distance is a number that denotes how believable an entire routing protocol is on a single router. The lower the number, the better, or more believable the routing protocol.
    Route Type Administrative Distance

    • Static 1
    • IGRP 100
    • RIP 120
43. What is the basic characteristic of switches and hubs?
    1. Hubs cannot filter frames.
    2. Using hubs is costly with regard to bandwidth availability.
    3. Switches do and can not forward broadcasts.
    4. Switches are more efficient than hubs in processing frames.
    5. Switches increase the number of collision domains in the network.

    Answer :E

    Explanation:Switches increases the number of collisions domains in the network. Switches that are configured with VLANs will reduce the size of the collision domains by increasing the number of collision domains in a network, but making them smaller than that of one big, flat network.

44. When you consider half-duplex and full-duplex Ethernet, what are unique for half-duplex Ethernet? (Select two options.)
    1. Half-duplex Ethernet operates in a shared collision domain.
    2. Half-duplex Ethernet operates in an exclusive broadcast domain.
    3. Half-duplex Ethernet has efficient throughput.
    4. Half-duplex Ethernet has lower effective throughput.
    5. Half-duplex Ethernet operates in an exclusive collision domain.

    Answer :A, D

    Explanation:A single device could not be sending a frame and receiving a frame at the same time because it would mean that a collision was occurring. So, devices simply chose not to send a frame while receiving a frame. That logic is called half-duplex logic. Ethernet switches allow multiple frames to be sent over different ports at the same time. Additionally, if only one device is connected to a switch port, there is never a possibility that a collision could occur. So, LAN switches with only one device cabled to each port of the switch allow the use of full-duplex operation. Full duplex means that an Ethernet card can send and receive concurrently.