专业英语模拟试题

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Remark: Except Question 5, All the Questions Should Be Answered in English.

特别提醒：除了第5题，其余题目均应用英语作答

1.Full forms of abbreviations(写出缩写的完整形式)（20points）

TSAP

QPSK

HTTP

CDMA

MIME

OSI

IMAP

ICMP

ARP

IoT

答案见书上

2. Answering the following questions (回答下列问题)（20points）

(1)What is OSPF ?

⏹OSPF is a link-state protocol that uses flooding of link state information and a Dijkstra least-cost path algorithm.

⏹With OSPF, a router constructs a complete topological map of the entire autonomous system.

⏹The router obtains its routing table by using the shortest path algorithm.

⏹Compared with RIP, it is adapt to larger autonomous systems with less than 200 hops.

(2)How does DNS Work?

The essence of DNS is a hierarchical, domain-based naming scheme.

Work Flows: To map a name onto an IP address, an application program calls a library procedure called the resolver. The resolver sends a UDP packet to a local DNS server, which then looks up the name and returns the IP address to the resolver, then returns it to the caller. After getting the IP address, the program can then establish a TCP connection with the destination or send it UDP packets.

(3)Could you explain how many layers do the TCP/IP have and what are they?

The TCP/IP model organizes the communication task into four independent layers:

●the host-to-network layer

●the Internet layer

●the transport layer

●the application layer

(4)What is the operating principle of CSMA/CD?

⏹CSMA/CD (Carrier Sense Multiple Access with Collision Detection).

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⏹Firstly, when a station wants to transmit, it senses the channel. If the channel is idle, the station sends the data immediately.

⏹If the channel is busy, it continues to sense the channel until the channel is idle. Secondly, stations detect the collision.

⏹If two stations sense the channel to be idle and begin transmitting simultaneously, the collision happens and the transmission

stops abruptly as soon as the collision is detected by any station.

⏹Thirdly, if a collision occurs, the colliding stations wait a random time, using the Ethernet binary exponential back-off algorithm,

and then try again later.

3. Filling in the blanks(填空) （20points）

（1）A cipher is a character-for-character or bit-for-bit transformation, without regard to the linguistic structure of the message.

（2）The Java language is a programming language, which has a vocabulary, and .

（3）There are two approaches to create the hash tables: flooding algorithm and backward learning.

（4）Routing algorithms can be grouped into two major classes: non-adaptive and adaptive.

（5）Substitution ciphers preserve the of the plaintext symbols but them.

ACBDA

4. Chinese-English Translation(汉译英) （10points）

☐无线调制解调器：一种为无线计算机连网的调制解调器。

☐Wireless modem. A modem for wireless computer connected to network.

☐

☐无线网络：在网络中计算机和其他终端设备通过无线信道互相连接起来。

☐Wireless network. The computers and other terminals are connected by wireless channels in the network.

☐

☐客户机-服务器模式：用户有一些简单的机器成为客户机，还有一些功能强的计算机存有大量的数据成为服务器，把他们用网络来连接起来形成了客户机-服务器模式。

☐client-server model. Users have simpler computers, called clients; and there are some powerful computers called servers