CCNA第一章练习.docx

网际互联
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 munication session?
A. Send a different source port number.
B. Restart the virtual circuit(重启虚电路).
C. Decrease the sequence number(序列号).
D. Decrease the window size.
通过使用流量控制(默认时TCP使用窗口机制),接收方主机能够控制发送方主机。通过减小窗口尺寸,接受方主机能够降低发送方主机的发送速率,从而使得接收方主机的缓冲区不会产生溢出。
2. Which fields(字段) are contained within an IEEE frame header?(Choose two.)
A. Source and destination MAC address
B. Source and work address
C. Source and destination MAC address and source and work address
D. ECS field
帧有源MAC地址和目的MAC地址、Ether-Type字段(用来识别网络层协议)、数据和FCS字段(用来保存CRC的结果)。
3. Which layer(层) 1 devices can be used to enlarge the area covered by a single LAN segment(局域网部分)?(Choose two.)
A. Switch(交换机)
B. NIC(网卡)
C. Hub(集线器)
D. Repeater(中继器)
E. RJ45 transceiver
并不是你真的想扩大冲突域,但是集线器(多端口中继器)会产生一个大的冲突域。
4. Segmentation(分隔) of a data stream(数据流) happens at which layer of the OSI model?
A. Physical(物理层)
B. Data Link(数据链路层)
C. Network(网络层)
D. Transport(传输层)
传输层从高层接收大的数据流,并将它们分为小一些的数据块,称其为数据段。
5. Which of the following describe router functions?(Choose four.)
A. Packet switching(包交换)
B. Collision prevention
C. Packet filtering(数据包过滤)
D. Broadcast domain enlargement
E. munication(互联网络通信)
F. Broadcast forwarding
G. Path selection(路径选择)