练习一 网络互连

CCNA Guide 640-802 chapter one1. A receiving host has failed to receive all of the segments that it should acknowledge. What can the host do to improve the reliability of this communication session?A. Send a different source port number.B. Restart the virtual circuit.C. Decrease the sequence number.D. Decrease the window size.2. Which fields are contained within an IEEE Ethernet frame header (Choose two.)A. Source and destination MAC address.B. Source and destination network address.C. Source and destination MAC address and source and destination network address.D. FCS field.3. Which layer 1 devices can be used to enlarge the area covered by a single LAN segment? (Choose two.)A. SwitchB. NICC. HubD. RepeaterE. RJ45 transceiver4. Segmentation of a data stream happens at which layer of the OSI model?A. PhysicalB. Data LinkC. NetworkD. Transport5. Which of the following describe router functions? (Choose four.)A. Packet switchingB. Collision preventionC. Packet filteringD. Broadcast domain enlargementE. Internetwork communicationF. Broadcast forwardingG. Path selection6. Routers operate at layer____. LAN switches operate at layer____. Ethernet hubs operate at layer____. Word processing operates at layer____.7. When data is encapsulated, which is the correct order?A. Date, frame, packet, segment, bitB. Segment, data, packet, frame, bitC. Data, segment, packet, frame, bitD. Data, segment, frame, packet, bit8. Why does the data communication industry use the layered OSI reference model? (Choose two.)A. It divides the network communication process into smaller and simpler components, thus aiding componentdevelopment, design, and troubleshooting.B. It enables equipment from different vendors to use the same electronic components, thus saving research anddevelopment funds.C. It supports the evolution of multiple competing standards and thus provides business opportunities for equipmentmanufacturers.D. It encourages industry standardization by defining what functions occur at each layer of the model.E. It provides a framework by which changes in functionality in one layer require changes in other layers.9. What are two purposes for segmentation with a bridge?A. To add more broadcast domainsB. To create more collision domainsC. To add more bandwidth for usersD. To allow more broadcasts for users10. Which of the following are unique characteristics of half-duplex Ethernet when compared to full-duplex Ethernet?(Choose two.)A. Half-duplex Ethernet operates in a shared collision domain.B.Half-duplex Ethernet operates in a private collision domain.C. Half-duplex Ethernet has higher effective throughput.D. Half-duplex Ethernet has lower effective throughput.E. Half-duplex Ethernet operates in a private broadcast domain.11. You want to implement a network medium that is not susceptible to EMI. Which type of cabling should you use?A. Thicknet coaxB. Thinnet coaxC. Category 5 UTP cableD. Fiber-optic cable12. Acknowledgments, sequencing, and flow control are characteristics of which OSI layer? _____13. Which of the following are types of flow control? (Choose all that apple.)A. BufferingB. Cut-throughC. WindowingD. Congestion avoidanceE. VLANs14. Which of the following types of connections can use full duplex? (Choose three.)A. Hub to hubB. Switch to switchC. Host to hostD. Switch to hubE. Switch to host15. What is the purpose of flow control?A. To ensure that data is retransmitted if an acknowledgment is not receivedB. To reassemble segments in the correct order at the destination deviceC. To provide a means for the receiver to govern the amount of data sent by the senderC. To regulate the size of each segment16. Which three statements are true about the operation of a full-duplex Ethernet network?A. There are no collisions in full-duplex mode.B. A dedicated switch port is required for each full-duplex mode.C. Ethernet hub ports are preconfigured for full-duplex mode.D. In a full-duplex environment, the host network card must check for the availability of the network media beforetransmitting.E. The host network card and the switch port must be capable of operating in full-duplex mode.17. What type of RJ45 UTP cable is used between switches?A. Straight-throughB. Crossover cableC. Crossover with a CUS/DUSD. Crossover with a router in between the two switches18. How does a host on an Ethernet LAN know when to transmit after a collision has occurred? (Choose two.)A. In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously.B. In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting.C. You can improve the CSMA/CD network by adding more hubs.D. After a collision, the station that detected the collision has first priority to resend the lost data.E. After a collision, all stations run a random backoff algorithm. When the back off delay period had expired, all stationshave equal priority to transmit data.F. After a collision, all stations run aidenticalbackoff algorithm. When the backoff delay period has expired, all stations haveequal priority to transmit data.19. What type of RJ45 UTP cable do you use to connect a PC’s COM port to a router or switch console port?A. Straight-throughB. Crossover cableC. Crossover with a CSU/DSUD. Rolled。