1. [多选题]As the Ezonexam network administrator, you are required to have a firm understanding of the OSI model. Why does the data communication industry use the layered OSI reference model? (Choose two)
A. It enables equipment from different vendors to use the same electronic components, thus saving research and development funds
B. It encourages industry standardization by defining what functions occur at each layer of the model
C. It divides the network communication process into smaller and simpler components; thus aiding component development, design and troubleshooting
D. It provides a means by which changes in functionality in one layer require changes in other layers
E. It supports the evolution of multiple competing standards and thus provides business opportunities for equipment manufacturers
2. [单选题]VLAN主干协议VTP的默认工作模式是()
A. 服务器模式
B. 客户端模式
C. 透明模式
D. 以上三者都不是
3. [多选题]Which of the following are types of flow control? (Choose three)
A. Buffering
B. Cut-through
C. Windowing
D. Congestion avoidance
E. Load balancing
4. [单选题]When is a switched network that is running the Spanning Tree Protocol considered to be fully converged?
A. when all switches have the same BID as the root switch
B. when all switches have received the MAC address of each neighboring switch
C. when every enabled switch port has been assigned a unique identifier
D. when every operating switch port is in either the blocking or forwarding state
E. when all switches are in either client, server, or transparent mode
5. [单选题]配置路由器时，封装PPP协议的命令是：()
A. encap ppp
B. ppp
C. group ppp
D. int ppp
6. [单选题]两个VLAN之间要想通信，应该使用的设备是（）
A. 集线器
B. 二层交换机
C. 路由器
D. PC机
7. [多选题]请选出交换机处理帧的三种模式：()
A. 直通模式
B. 存储转发模式
C. 侦测模式
D. 分段模式
E. 阻塞模式
8. [单选题]SMTP工作在OSI哪一层（）
A. 会话层(session layer)
B. 表示层
C. 传输层
D. 应用层
9. [单选题]关于帧中继(frame relay)的说法，正确的是（）
A. 速率最大为1Mbit/s
B. 不提供差错校验功能
C. 可以偷占带宽
D. 数据传输质量高于DDN
10. [多选题]Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two answer choices.)
A. Full-duplex Ethernet uses CSMA/CD to prevent collisions.
B. Half-duplex Ethernet uses a loopback circuit to detect collisions.
C. A full-duplex Ethernet card allows 20Mbps for data transmission.
D. Full-duplex Ethernet makes use of two pairs of wires for data.
E. An Ethernet hub can operate both half and full duplex simultaneously.
