尔雅Introduction of Information Communication Network_1章节答案(学习通2023题目答案)
61 min read尔雅Introduction of Information Communication Network_1章节答案(学习通2023题目答案)
1.1 Application,尔雅 definition, development and classification随堂测验
1、Which of the following descriptions of network classification is 节答wrong
A、A network connecting digital terminal devices such as computers within 10m of the user's computer is 案学a WSN
B、A network covering 10m~10km is 习通a LAN
C、A network covering 10~100km is 题目MAN
D、A networks covering 100~1000km become WANs
2、答案Which of the following descriptions of WAN characteristics is 尔雅wrong
A、WAN is 节答a public data network
B、WAN provide telecommunication-level services to users
C、案学WAN research focuses on broadband core switching technologies
D、习通The题目 core technology of WAN is line switching technology
3、The答案 computer network is composed of network hardware system and network software system.
4、In general,尔雅 network nodes have duality, which can be used as both access nodes and transfer nodes.
1.2 The concept of exchange and the time delay随堂测验
1、Among following descriptions of the datagram transmission mode,节答 which is wrong?
A、Different packets of the same message can pass through the communication subnetwork through different transmission paths.
B、案学When different packets of the same message arrive at the destination host, they may be out-of-order, duplicated or lost.
C、Each packet must carry a destination address and a source address during transmission
D、Datagram mode is suitable for long message and session communication
2、Message exchange adopts store-and-forward mechanism.
3、At present, packet switching is the most commonly used switching mode in communication networks.
4、The delay of message exchange is very short, so it is still the main exchange mode.
5、Circuit switching is divided into three stages: establishing connection, communicating and releasing connection.
1.3 Network architecture and reference model随堂测验
1、Which is wrong among the following descriptions of the OSI environment
A、7 layers from the application layer to the physical layer of the host shown by the dotted line of the OSI environment and the communication subnet
B、The physical transmission medium connecting the host is included in the OSI environment
C、If a host is not connected to the compute network, it may not need hardware and software to realize functions from the physical layer to the application layer
D、The processes of the host are controlled by the local operating system and do not belong to the OSI environment
2、Among the following descriptions of the data transmission process in OSI environment, the wrong description is
A、The data generated by the application process of source host is transmitted vertically and layer by layer from the application layer
B、The presentation layer only exchanges data formats without adding protocol headers
C、The target host reads the header layer by layer according to the protocol of each layer, and executes the action specified by the protocol
D、Does not need user intervention in the whole process
3、In the OSI reference model, the first level to provide end-to-end services from bottom to top is
A、Physical layer
B、Data Link Layer
C、Network layer
D、Transport layer
4、Among the following components, which does not belong to the network architecture
A、Network hierarchy
B、Protocols used at each layer
C、Protocol details
D、Functions implemented at each layer
5、The network layer protocol in TCP/IP system provides
A、Connectionless and unreliable packet service
B、Connectionless and reliable packet service
C、Virtual circuit services with unreliable connections
D、Virtual circuit service with reliable connection
Unit test
1、Which is wrong among the following descriptions of network protocols and protocol elements?
A、Protocol presents network functions
B、Semantic is to do what
C、Grammar means how to do it
D、Time sequence indicates the order of process
2、Which is wrong among the following descriptions of the concept of network architecture
A、Network architecture is a collection of network hierarchy model and protocols at each layer
B、All computer networks should follow OSI architecture.
C、The network architecture is abstract, and the technology to realize the network protocol is concrete
D、The network architecture accurately defines the functions that the computer network should realize
3、Which is wrong among the following advantages of the research method of network architecture
A、Each layer is independent with each other
B、Easy to implement and standardize
C、Allowing interlayer communication is a sign of flexibility of OSI reference model
D、Changes in implementation technology will not affect the work of the whole system
4、Which is wrong among the following description of the basic concepts of OSI reference model
A、Term ‘Open’ in "OSI Reference Model" refers to being able to be used for any kind of operating system for computer
B、The OSI reference model defines the hierarchy of open systems and the interrelationships between the hierarchies
C、The service definition of OSI explains the services provided by each layer in detail, and does not involve the specific implementation method of interfaces
D、OSI reference model is not a standard, but a conceptual framework used in formulating standards
5、Which is wrong among the following descriptions of the 7-level division principle of OSI reference model
A、Each host in the network can have different levels
B、The same layer of different hosts has the same function
C、Adjacent layers in the same host communicate through the interface
D、The same layer of different hosts realizes the communication between the same layers through the protocol
6、Which is wrong among the following descriptions of basic features of the physical layer
A、Bottom layer of the OSI reference model
B、Establishing, managing and releasing physical connections between communicating hosts
C、Realizing transparent transmission of the bit stream
D、Data transmission unit is a byte
7、Among the following basic features(or properties) of the data link layer, which is the wrong description
A、Adjacent high layer is the network layer
B、Data link can be established after the physical connection is released
C、Adopting the method of error control and flow control to make the physical line with errors become the physical link without errors
D、The data transmission unit of the data link layer is a frame
8、Among the following basic features of the network layer, which is the wrong description
A、Adjacent high layer is the transport lay
B、Selecting an appropriate transmission link for the packet through the communication subnetwork by routing selection algorithm
C、Realizing the functions of flow control, congestion control and network security
D、The data transmission unit of the network layer is a packet
9、Among the following basic features of the transport layer, which is the wrong description
A、Adjacent lower layer is the network layer
B、Adjacent high layer is the presentation layer
C、Providing reliable end-to-end connection and data transmission services for compute processes distributed in different geographical locations
D、Shielding details of low-level data communication to the high level
10、Which is wrong among the following descriptions of OSI environment
A、7 layers from the application layer to the physical layer of the host shown by the dotted line of the OSI environment and the communication subnet
B、The physical transmission medium connecting the host is included in the OSI environment
C、If a host is not connected to the compute network, it may not need hardware and software to realize functions from the physical layer to the application layer
D、The processes of the host are controlled by the local operating system and do not belong to the OSI environment
11、Among the following descriptions of the data transmission process in OSI environment, the wrong description is
A、The data generated by the application process of source host is transmitted vertically and layer by layer from the application layer
B、The presentation layer only exchanges data formats without adding protocol headers
C、The target host reads the header layer by layer according to the protocol of each layer, and executes the action specified by the protocol
D、Does not need user intervention in the whole process
12、Among the following characteristics of the transport layer, which is wrong
A、Realizing distributed process-communication in network environment
B、TCP is a reliable, connection-oriented, byte-stream-oriented transport layer protocol
C、An unreliable, connectionless transport layer protocol for UDP
D、Data unit of protocol is a packet
13、What is correct in describing the relationship between the nth layer and the n+1 layer in OSI reference model
A、The nth layer provides services for the n+1 th layer
B、The n+1 layer adds a header to the message received from the nth layer
C、The n-layer header is used to coordinate protocol actions between the n-layers of adjacent nodes
D、The nth lay and the n+1 th layer have no influence on each other
14、In OSI reference model, the first level to provide end-to-end services from bottom to top is
A、Physical layer
B、Data Link Layer
C、Network layer
D、Transport layer
15、Among the following components, which does not belong to network architecture
A、Network hierarchy
B、Protocols used at each layer
C、Agreement details
D、Functions implemented at each layer
16、The network layer protocol in TCP/IP system provides
A、Connectionless and unreliable packet service
B、Connectionless and reliable packet service
C、Virtual circuit services with unreliable connections
D、Virtual circuit service with reliable connection
17、The resources shared by the computer network are
A、Router and switch
B、Domain name, network address and MCA address
C、Computer files and data
D、Computer software, hardware and data
18、Which of the following descriptions of network classification is wrong
A、A network connecting digital terminal devices such as computers within 10m of the user's computer is a WSN
B、A network covering 10m to 10km is a LAN
C、A network covering 10 ~ 100km is a MAN
D、A network covering 100 ~ 1000km is a WAN
19、Which of the following descriptions of WAN characteristics is wrong
A、WAN is a public data network
B、WAN shall provide telecommunication-level services for users
C、The focus of WAN research is broadband core switching technology
D、The core technology of WAN is line switching technology
20、Among the following descriptions of broadband metropolitan area network, the wrong description is
A、Optical fiber transmission network is the foundation of broadband metropolitan area network
B、The integration of traditional telecommunication, cable TV and IP services has become the core service of broadband metropolitan area network
C、Switches in Layer 2 is the core equipment of broadband metropolitan area network
D、Expanding the scale and service quality of broadband access is the key to developing the application of broadband metropolitan area network
21、The computer network is composed of network hardware system and network software system.
22、The host computer belongs to the switching node of the network node in the computer network.
23、In general, network nodes have duality, and can be used as both access nodes and transfer nodes.
24、Physical links do not have the capability of data transmission control.
25、Common transmission media in computer networks include twisted pair, coaxial cable and optical fiber.
Unit homework
1、One day you return from school to your home with two mobile hard disks on your bike. Assume that the distance from home to school is 2.5 km, each mobile hard disk can hold 500GB bytes, and your average riding speed is 18km/h. What is your equivalent data-transmission-rate at this time?
2、A client server model transmits information through a satellite network. It is known that the satellite is a synchronous satellite. What is the shortest delay in call and response?
3、A 1920*1080 wallpaper is known , and each pixel is represented by 3 bytes. If this image is not compressed and is transmitted on a 56kbps modem channel, how long will it take to complete the transmission?
4、What is the biggest difference between connection-oriented and connectionless communication?
5、Please explain why the hierarchical model is adopted in the network architecture from at least two perspectives?
2 Physical Layer
2.1 Model and Protocol, Basic Concepts and Transmission Media随堂测验
1、Among the following four transmission media, which has the widest bandwidth, the smallest signal transmission attenuation and the strongest anti-interference capability?
A、Twisted pair
B、Coaxial cable
C、Optical fiber
D、Microwave
2、What are the benefits of shielding in cables?
A、Reduce signal attenuation
B、Reduce electromagnetic interference radiation
C、Reduce physical loss
D、Reduce cable impedance
3、Physical layer is the specific physical device or specific transmission medium connecting the computers.
4、In computer networks, carriers used to transmit information such as twisted pair, coaxial cable and optical fiber are called transmission media.
5、A data transmission mode that allows signals to be transmitted in two directions but can only be transmitted in one direction at each moment is called simplex communication.
2.2 Digital Modulation随堂测验
1、The basis of analog signal transmission is carrier wave. Which is not the 3 elements of carrier wave?
A、Amplitude
B、Frequency
C、Period
D、Phase
2、The following figure shows Manchester coding. What is the binary data shown in this figure?
A、01011
B、01101
C、10100
D、01100
3、In order to increase the transmission distance of the analog transmission system, what equipment should be used?
A、Bridge
B、Amplifier
C、Router
D、Switch
4、Analog communication system usually consists of source, modulator, channel, demodulator and sink. The electrical signal before modulation is called analog signal, and the modulated signal is called digital signal.
5、In analog data communication system, digital data can be modulated according to different elements of carrier wave. There are three methods of modulating signals, namely amplitude keying, frequency shift keying and phase shift keying.
2.3 Multiplexing随堂测验
1、Which is wrong among the following descriptions of the concept of time division multiplexing?
A、Time division multiplexing divides the time used by the line into a plurality of time slices
B、Time division multiplexing is divided into synchronous time division multiplexing and statistical time division multiplexing
C、Statistic time division multiplexing assign time slices to each channel in advance
D、The concepts of "frame" used in time division multiplexing and the "frame" in data link layer function differently
2、Which is wrong among the following descriptions of the technical characteristics of statistical time division multiplexing,?
A、The English abbreviation of statistical time division multiplexing is "ATDM"
B、Statistic time division multiplexing allows dynamic allocation of time slices
C、The data sent out by statistical time division multiplexing does not need to have addresses of both receiving and receiving parties
D、The multiplexing device may also adopt the store-and-forward mode to adjust the transmission rate of the communication line
3、Multiplexing technology can be divided into three basic modes: frequency division multiplexing, wavelength division multiplexing and time division multiplexing.
4、The process of pulse coding modulation can be simply divided into two processes: sampling and coding.
5、In cellular mobile communication systems, there are three commonly used multiple access technologies: frequency division multiple access, time division multiple access and code division multiple access.
2.4 PSTN随堂测验
1、In ATM technology, cells are the basic unit of data transmission, and their length is:
A、43B
B、5B
C、48B
D、53B
2、Which is incorrect among the following descriptions of packet switching?
A、The datagram mode is flexible and fast
B、There are two mode of packet exchange: datagram mode and virtual circuit mode
C、The packet switching technology has high error rate of data transmission and low line utilization rate
D、The virtual circuit mode can establish several logical virtual circuits on one physical circuit, making users feel as if there are several physical links
3、What is the meaning of "asynchronous" in Asynchronous Transfer Mode (ATM) technology?
A、Adopts asynchronous serial communication technology
B、Adopts asynchronous control mode
C、Periodically inserts into ATM cells
D、Inserts into ATM cells at any time
4、Which is wrong among the following descriptions of T1 carrier?
A、T1 carrier rates are designed for time division multiplexing of pulse code modulation PCM
B、T1 system multiplexed 24 channels of digital voice channels on one communication line
C、PCM encoder alternately inserts 24 channels of 8bit digital voice signals into the designated position in the frame
D、The data transmission rate of T1 carrier is 2.048 Mbps
5、Which is wrong among the following descriptions of the comparison between ADSL and HFC?
A、ADSL backbone uses optical fiber and HFC backbone uses broadband coaxial cable
B、ADSL’s user-access uses telephone line, HFC’s user-access uses CATV cable
C、The telephone line connected to the ADSL modem is dedicated to the user, and the CATV cable connected to HFC user is shared
D、ADSL operators can make a commitment to subscribers' broadband, whereas HFC operators generally do not make an explicit commitment
Unit test
1、Among the following descriptions of the physical layer, which is wrong?
A、The main task of the physical layer is to ensure the correct transmission of the bit stream through the transmission medium
B、The transmission media connecting physical layer may have different types, such as optical fiber and wireless communication lines, etc
C、Protocols of physical layer can be divide into two types: point-to-point communication lines and broadcast-based lines
D、Physical layer shields the difference between Ethernet and IP
2、Among the following descriptions of data transmission rate, which is wrong?
A、Data transmission rate represents the number of transmitted binary bits per second
B、For binary data, that data transmission rate is S=1/T (bps)
C、Common data transmission rate units are: 1Mbps = 1.024 × 10e6 bps
D、Data transmission rate is one of the important technical indexes to describe the performance of data transmission system
3、Which is wrong among the following descriptions of Nyquist's criteria?
A、Used to calculate "bandwidth" and "rate" in the state of random noise
B、Use a calculation model of narrow pulse signal passing through an ideal communication channel
C、Maximum transmission rate of the line is numerically equal to 2 times of the channel bandwidth
D、The unit of transmission rate is bps
4、If the following is a Manchester encoded waveform of 8-bit data, what is this data?
A、10110100
B、01001011
C、11010010
D、01011100
5、Which is wrong among the following statements about satellite communication?
A、Satellite communication has a large communication distance and a wide coverage range
B、It is easy to realize broadcast communication and multiple access communication by using satellite communication
C、The advantages of satellite communication are that it is not affected by climate and its bit error rate is very low
D、High communication cost and large delay are the shortcomings of satellite communication
6、When FSK modulation is performed on a signal, and if the carrier frequency is fc and the original/modulated signal frequencies are f1 and f2 respectively (f1 < f2), what is the relationship between the three?
A、fc-f1=f2-fc
B、f2-f1=fc
C、f2+f1=fc
D、f1·f2=fc
7、Which is the modulation and demodulation technology mainly used among the following communication modes?
A、Analog channel transmits digital data
B、Analog channel transmit analog data
C、Digital channel transmit digital data
D、Digital channel transmit analog data
8、What is the channel communication mode in which both communication parties can transmit data simultaneously at the same time?
A、Half duplex communication
B、Simplex communication
C、Datagram
D、Full duplex communication
9、Generally speaking, for high-speed local area networks with large volume, which should be selected in order to obtain higher performance among following media?
A、Coaxial cable
B、Optical Fiber
C、Twisted pair
D、Wireless
10、What are the three basic forms of analog data coding?
A、BSK, PSK, LSK
B、ASK, FSK, PSK
C、AKS, FKS, PKS
D、BKS, PKS, FKS
11、When a digital signal is transmitted in an analog transmission system, what are required at the transmitting and the receiving ends respectively?
A、Modulator and Demodulator
B、Demodulator and Modulator
C、Encoder and decoder
D、Decoder and encoder
12、Dividing the frequency bandwidth of the physical channel into several subchannels, each subchannel transmitting one signal. What is this multiplexing technology called?
A、Synchronous time division multiplexing
B、Space division multiplex
C、Asynchronous time division multiplex
D、Frequency division multiplex
13、During data transmission, local telephone network has a physical connection line between the source node and the destination node, which constitute intermediate nodes. What is the technology adopted by this local telephone network called?
A、Message Exchange
B、Line Switching
C、VCP switch
D、Datagram packet exchange
14、Which one among the following multiplexing technologies has the function of dynamically allocating time slots?
A、Synchronous time division multiplexing
B、Statistical time division multiplex
C、Frequency division multiplex
D、Wavelength division multiplexing
15、In digital communication, what is the technology to keep the time reference between the transceiver and the transceiver consistent?
A、Switching Technology
B、Synchronization Technology
C、Coding Technology
D、Transmission Technology
16、What is the coding method which represents the digital signal 1, 0 by changing the phase value of the carrier signal?
A、ASK
B、FSK
C、PSK
D、NRZ
17、Shannon's theorem describes the relationship between "bandwidth" and "rate" from a quantitative point of view. In the formula of Shannon's theorem, the parameters related to the maximum transmission rate of the channel mainly includes channel bandwidth and ()?
A、Frequency characteristics
B、Signal-to-Noise Ratio
C、Phase Characteristics
D、Noise Power
18、The packet switching mode is to divide a long message into several shorter packets with a fixed maximum length. Different from packet switching, packet switching has ( )?
A、Message Header
B、End of message
C、Routing
D、Group Number
19、Generally speaking, digital transmission can get higher signal quality than analog transmission, because?
A、The repeater can regenerate digital pulses to remove signal distortion, and the amplifier amplifies the analog signal as well as the analog signal distorted
B、Digital signals are smaller than analog signals and are not prone to distortion
C、Analog signals are continuous and are not prone to distortion
D、Digital signal is easier to sample than analog signal
20、Among the following data exchange modes, the transmission delay of data through the network is long and unstable. Which cannot be used for voice data transmission?
A、Line Switching
B、Message exchange
C、VCP switch
D、Datagram packet exchange
21、Data transfer rate is the number of bytes transferred per second.
22、Modem is only used to convert digital signals into analog signals and transmit them on the line.
23、Manchester code and differential Manchester code belong to self-contained clock code.
24、Bit rate describes the number of binary bits that make up the code transmitted per second in computer communication.
25、Data sent by statistical time division multiplexing need to have addresses of both transceiver and transceiver.
Unit homework
1、What is the signal-to-noise ratio required to use T1 line on 50kHz line?
2、It is known that the data transmission rate is 14400bps and the number of phases k=16 for polyphase modulation. Find: Modulation Rate?
3、Is there any difference between the demodulation part of the modem and the encoding part of the codec? If so, what is the difference? (Both convert analog signals into digital signals.)
4、Assuming that A, B and C transmit bit 0 simultaneously through a CDMA system, their time slice sequence is A: (-1-1 +1 +1-1 +1 +1) B: (1-1 +1-1 +1 +1-1) C: (1 +1-1 +1 +1-1-1) What is the time slice sequence obtained from the result?
5、It is known that the OC-1 rate defined by SONET is 51.840 Mbps. Calculation: What is the corresponding rate for STM-4?
3 Data Link Layer
3.1 Basic concepts and design points随堂测验
1、What does not belong to the three possible services that are provided by data link layer?
A、Connectionless service without acknowledgement
B、Connectionless service with confirmation
C、Connection-oriented service without acknowledgement
D、Confirmed connection-oriented service
2、The data link layer encapsulates the packets obtained from the network layer into frames for transmission, each frame containing a frame header and a payload domain.
3、In byte filling, if the escaped byte appears in the middle of the data, there is no need to insert the escaped byte in front.
4、In bit filling, when the sender's data link layer encounters five consecutive bits "1" in the data, it automatically fills one bit "0" in the output bit stream. And there is no need to fill when 5 consecutive bits "0" are encountered.
5、Sometimes due to hardware problems, some frames are completely lost. At this time, the receiver will not respond, while the sender has been waiting because it has not received feedback information. Introducing timers in the data link layer can solve this problem.
3.2 Error detection and correction随堂测验
1、In polynomial coding, arithmetic operations of polynomials have carry in addition and borrow in subtraction.
2、Error control codes can be divided into error detection codes and error correction codes. Among them, the error detection code is the code of automatic error detection; An error correcting code is a code that can not only detect errors but also automatically correct them.
3、The so-called error is that in data communication, the data received after the data through the communication channel is inconsistent with the data sent.
4、Generally speaking, most of the errors in transmission are caused by noise. Errors caused by thermal noise are called burst errors, while errors caused by impact noise are called random errors.
5、In the odd check scheme, the check bit of binary sequence 0101101 is "0".
3.3 Elementary protocols随堂测验
1、In data communication, when data transmission errors occur, the error control method that the sender does not need to retransmit the data is?
A、ARQ
B、FEC
C、BEC
D、CRC
2、The error detection and correction capability of a code depend on its Hamming distance. In order to detect d-bit errors, what is the code with Hamming distance?
A、d
B、d+1
C、d+2
D、2d +1
3、What is the frame synchronization method used by HDLC protocol?
A、Beginning and tail mark method using bit filling
B、Beginning and tail delimiter method filled with characters
C、Byte counting method
D、Illegal coding method
4、In a simplex stop-wait protocol, data traffic is simplex, only from the sender to the receiver, so the communication channel between the two data link layers only needs to have the capability of unidirectional transmission of information.
5、The most basic function of the data link layer is to provide reliable and transparent services to users at this layer.
3.4 Sliding window protocols随堂测验
1、What kind of control is flow control actually?
A、Data flow of the sender
B、Data flow of the receiver
C、Transmit and receiving data flow of both sides
D、Data flow between any two nodes on that link
2、The error control method by which the receiving end can not only detect the error, but also determine the location where the error occurred. What is this control method?
A、Feedback retransmission ARQ
B、Forward error correction FEC
C、Stop and wait method
D、Select and retransmit
3、From the point of view of sliding window, when the transmission window = 1 and the reception window = 1, what is the equivalent of feedback retransmission?
A、Selection and retransmission of continuous work
B、Pull back of continuous work
C、Stop and wait
D、Work continuously
4、In the sliding window protocol, the sending window of the sender and the receiving window of the receiver must have the same upper and lower bounds.
5、In the actual measurement of a data transmission system, the more binary bits are measured, the closer it will be to the true bit error rate.
3.5 Example data link protocols随堂测验
1、Which layer does SLIP or PPP belong to?
A、Physical layer
B、Transport layer
C、Network layer
D、Data link layer
2、Suppose a WAN has four networks connected in parallel by dedicated telephone lines and using TCP/IP, NWLINK, and NETBEUI protocols. If communication between these networks requires data compression, which should be used among the following dial-up communication protocols?
A、SLIP
B、PPP
C、DLC
D、NCP
3、Among the common operation modes in HDLC, what is the transmission process that can only be started by the master station?
A、Asynchronous balanced mode
B、Unbalanced asynchronous response mode
C、Non-equilibrium normal response mode
D、A, B, C can all
4、Which does not belong to the TCP/IP protocol family among the following protocols?
A、ICMP
B、TCP
C、DNS
D、HDLC
5、In PPP protocol, Link Control Protocol/LCP is used to establish, configure, manage and test data link connections. And the Network Control Protocol/NCP is used to establish and configure different network layer protocols.
Unit test
1、In order to carry out error control, the transmitted data frame must be checked. Which kind of verification method is widely used in LAN?
A、Parity
B、Hamming
C、Gray
D、Cyclic Redundancy (CRC)
2、Which is the most accurate description of the characteristics of CRC among the following options?
A、Check each character one by one
B、Can check out more than 99% of errors
C、The error with even number of bit errors cannot be checked
D、Is not as reliable as the parity check method
3、The types of errors in data transmission mainly include burst errors and ( )?
A、Calculation error
B、Parity error
C、Random error
D、CRC check error
4、In an ideal channel, data is error-free from the sending end to the receiving end, but in practical application, data transmission will produce errors. Which one is not a factor affecting the error due to physical transmission medium?
A、Abnormality and attenuation of signal amplitude, frequency and phase randomly generated on physical lines
B、Echo effect caused by reflection of electrical signals on the line
C、The compression ratio of data is too high, resulting in errors in transmission that cannot be overcome
D、String interference between adjacent lines, as well as lightning, electromagnetic interference, etc
5、The error detection and correction capability of a code depend on Hamming distance. In order to correct d-bit errors, what is the code with Hamming distance?
A、d
B、d+1
C、d+2
D、2d +1
6、What is the check code that can detect all odd errors, single bit errors, double bit errors and all burst errors which are less than or equal to the length of the check bit?
A、Hamming
B、CRC
C、Horizontal vertical parity check code
D、Horizontal or vertical parity check code
7、Flow control is one of the basic functions of the data link layer. Regarding flow control, which one is correct among following statements?
A、Only the data link layer has flow control
B、Not only the data link layer has flow control, but the flow control objects of each layer are the same
C、Not only does the data link layer have flow control, but the flow control objects of each layer are different
D、None of the above is right
8、Which of the three services provided by the data link layer to the network layer has the lowest quality of service and can be used to transmit information with high real-time requirements in occasions with low line bit error rate?
A、Connectivity-oriented service with confirmation
B、Connectivity-free service without confirmation
C、Confirmed Connectionless Service
D、Confirmed Connectionless Service
9、Which does not belong to the data link layer among following functions?
A、Frame Synchronization Function
B、Circuit Management Function
C、Error control function
D、Flow control function
10、The zero-bit insert/delete method states that if the sender is in a sequence of bits between two F flags. How many successive ones are detected, if it increments the number by one, regardless of whether the bit after it is 0 or 1.
A、4
B、5
C、6
D、8
11、Assume that the data link layer adopts go-back-N mode for error control, and the sender has already sent the frames numbered from 0 to 7. When the timer times out and the confirmation of frame 1 does not return, what is the number of frames that the sender needs to retransmit?
A、1
B、2
C、6
D、7
12、Among the common operation modes in HDLC, which one can start the transmission process by both the master station and the slave station?
A、Asynchronous balanced mode
B、Unbalanced asynchronous response mode
C、Non-equilibrium normal response mode
D、A, B, C
13、In order to avoid the disappearance of frames during transmission, what method does the data link layer adopt?
A、Number the sending frame
B、Cyclic redundancy code
C、Hamming code
D、Timer’s timeout retransmission
14、What is the probability that binary bits are transmitted incorrectly in the data transmission system called?
A、Error correction rate
B、Error rate
C、Minimum data transmission rate
D、Maximum data transmission rate
15、Which is wrong among the following descriptions of bit error rate?
A、Bit error rate is a parameter to measure the transmission reliability of the data transmission system under the normal working state
B、For an actual data transmission system, the lower the required bit error rate, the higher the cost of transmission system equipment
C、Bit error rate of the actual application data transmission system can reach zero
D、In the actual measurement of a data transmission system, the more binary bits are measured, the closer it will be to the true bit error rate
16、Which will only retransmit the wrong data frame among the following error control methods?
A、Continuous work
B、Stop and wait
C、Select and retransmit
D、Pull back
17、Which control method is primarily used by the sliding window protocol?
A、Error control
B、Safety control
C、Flow control
D、Congestion control
18、In CRC code calculation, a binary bit string can be associated with a unary polynomial containing only 0 or 1 coefficients. For example, the polynomial corresponding to bit string 101101 is（）?
A、x6+x4+x3+1
B、x5+x3+x2+1
C、x5+x3+x2 + x
D、x6+x5+x4+1
19、If the frame sequence number of the data link occupies 4 bits, the maximum sender window should be?
A、13
B、14
C、15
D、16
20、In CRC cyclic redundancy calculation, a binary bit string can be corresponded to a unary polynomial with only two coefficients of 0 or 1. For example, the string of binary numbers corresponding to the polynomial x5+x4+x+1 should be?
A、110011
B、111100
C、1100110
D、110010
21、Connectionless service without confirmation is very suitable for real-time communication, such as voice transmission.
22、In data frames, when control characters appear in the transmitted data, appropriate measures must be taken so that the receiving party does not mistake the data for control information. This ensures that the data link layer is connection-oriented.
23、The commonly used methods of frame synchronization are character counting method, delimiter method with byte filling, delimiter mark method with bit filling and physical layer coding violation method.
24、CRC verification cannot absolutely ensure the correct verification of data.
25、An important parameter to measure the coding performance is the bit error rate.
Unit homework
1、What are the main causes, error types and characteristics of transmission errors in the process of transmitting bit streams on physical lines?
2、Data link protocols almost always put CRC at the tail instead of the head. Why?
3、The bit rate of a channel is 4kbps and the transmission delay is 20ms.What range of frame sizes can stop-wait protocols achieve at least 50% efficiency?
4、A 100 km long cable runs at T1 data rate. The transmission speed of the cable is 2/3 of the speed of light in vacuum. How many bits can be accommodated in the cable?
5、A string of data 1011010111110111001 uses CRC check method. It is known that the binary number used for check is 1110101. What is the generated polynomial? What is the remainder?
4 The Medium Access Control Sublayer
4.1 MAC sublayer随堂测验
1、The sequential transmission of data packets is mainly completed by MAC sublayer.
2、The existence of MAC sublayer shields the differences of different physical links.
3、"Conflict" refers to the signal conflict that will occur when two or more users apply for communication at the same time and in the same link.
4、Static channel-allocation scheme is not suitable for occasions with many users and large traffic changes.
4.2 Protocosl of channel allocation随堂测验
1、No conflict will occur during the competition cycle in the CSMA/CD protocol.
2、In order to solve the problem that the basic bitmap protocol cannot be well expanded, the solution is to use binary station addresses.
3、Non-persistent CSMA protocol will listen to the channel before each transmission. If the channel is busy, it will continue to listen and send as soon as the channel is idle.
4.3 Ethernet随堂测验
1、Which is wrong the following description of Ethernet protocol, the error is
A、The length of conflict window specified in Ethernet protocol is 51.2 us
B、The data transmission rate in Ethernet is 10Mbps, and the collision window can send 521bit of data
C、64B is the minimum frame length for Ethernet
D、No conflict is found when the host sends the preamble code of a frame and the preamble delimiter of the frame, then the host can continue to send
2、Which is wrong among the following descriptions of Ethernet frame reception error
A、Frame address error means that the physical address of the received frame is not the address of this site
B、Frame check error means that CRC check is incorrect
C、Frame length error means that the frame length is incorrect
D、Frame bit dislocation mean that the frame length is not an integral multiple of 8 bits
3、Which is wrong among the following descriptions of the physical address of Ethernet
A、The physical address of Ethernet is also called MAC address
B、48-bit physical address of Ethernet allows 2 ^ 47 addresses to be assigned
C、The physical address of network card is written into the EPROM of host computer
D、The physical address of each network card is unique in the world
4.4 Data link layer switching随堂测验
1、Which is wrong among the following descriptions of the basic functions of switch
A、Establishing and maintaining a mapping table representing the corresponding relationship between MAC address and switch-port number
B、Establishing a virtual connection between port of the sending host and the receive host
C、Filtering and transferring of frames
D、Executing RIP routing protocol
2、A switch has 24 ports with10/100 Mbps and two 1Gbps ports. If all ports are operating in full duplex, the total bandwidth of the switch is the maximum
A、4.4 Gbps
B、6.4 Gbps
C、6.8 Gbps
D、8.8 Gbps
3、One of the main features of switching lans is their low switching transmission latency.The delay time of LAN switch is higher than that of bridge, but lower than that of router.
Unit test
1、Which is wrong among the following descriptions of the terms "shared media", "multiple access" and "conflict", the error is
A、Traditional Ethernet uses a coaxial cable as a bus to connect multiple nodes
B、Coaxial cables connecting multiple nodes are called "shared media"
C、The phenomenon that two or more nodes simultaneously use coaxial cables to send data at the same time is called "Collision"
D、The corresponding physical layer protocol is 10Base-T
2、Which is wrong among the following descriptions of LAN’s application environment
A、Under the same load condition, token network shows good throughput and low transmission delay
B、Under the same scale condition, the cost of token network is generally higher than that of Ethernet
C、Ethernet can adapt to office environment application
D、For industrial environments and applications that require strict real-time data transmission, Ethernet protocol is recommended
3、Which is wrong among the following descriptions of Ethernet protocol
A、The length of conflict window specified in Ethernet protocol is 51.2 us
B、The data transmission rate in Ethernet is 10Mbps, and the collision window can send 521bit of data
C、64B is the minimum frame length for Ethernet
D、No conflict is found when the host sends the preamble code of a frame and the preamble delimiter of the frame, then the host can continue to send
4、Which is wrong among the following descriptions of the random delay retransmission mechanism
A、The Ethernet protocol stipulates that the maximum number of retransmissions of a frame is 16
B、Ethernet adopts the cut-off binary exponential backward delay algorithm
C、Backward delay algorithm can be expressed as t=2^k*R*a
D、The maximum possible delay time is 1024 time slices
5、Which is wrong among the following descriptions of Ethernet frame reception error
A、Frame address error means that the physical address of the received frame is not the address of this site
B、Frame check error means that CRC check is incorrect
C、Frame length error means that the frame length is incorrect
D、Frame bit dislocation mean that the frame length is not an integral multiple of 8 bits
6、Which is wrong among the following descriptions of network card
A、Network card coverage MAC sublayer and physical layer of IEEE802.3 protocol
B、Network card realizes the electrical connection with the bus coaxial-cable through the transceiver
C、Network card is connected with the computer through an circuit-interface
D、Network card realizes the bridge function of connecting with other local-area networks
7、Which is wrong among the following descriptions of the physical address of Ethernet
A、The physical address of Ethernet is also called MAC address
B、48-bit physical address of Ethernet allows 2 ^ 47 addresses to be assigned
C、The physical address of network card is written into the EPROM of host computer
D、The physical address of each network card is unique in the world
8、Which is wrong among the following descriptions of the standard naming method for Ethernet physical layer
A、The naming method for physical layer of the standard Ethernet is: IEEE802.3 X Type-Y Name
B、X represents data transmission rate in Mbps
C、Y denotes the maximum length of the network segment in 1000m
D、Type indicate whether that transmission mode is baseband or band
9、Which is wrong among the following descriptions of the basic functions of switch
A、Establishing and maintaining a mapping table representing the corresponding relationship between MAC address and switch-port number
B、Establishing a virtual connection between port of the sending host and the receive host
C、Filtering and transferring of frames
D、Executing RIP routing protocol
10、A switch has 24 ports with10/100 Mbps and two 1Gbps ports. If all ports are operating in full duplex, the total bandwidth of the switch is the maximum
A、4.4 Gbps
B、6.4 Gbps
C、6.8 Gbps
D、8.8 Gbps
11、Which is wrong among the following descriptions of the similarities among CSMA/CD, Token Bus and Token Ring
A、The architecture follows the TCP/IP hierarchy model
B、Transmission medium mainly adopt coaxial cable, twisted pair and optical fiber
C、Transmitting and receiving data frames by shared media
D、The control of medium access adopts the distributed control method
12、Which is wrong among the following descriptions of Token Bus
A、Token Bus is a kind of local-area network that uses tokens as control nodes to access the common bus
B、Token is a data frame with a special structure
C、The sequence of token obtained by a defective node in advance form a logical ring shape
D、The maximum interval in which the node in the loop gets the token to send data is determined
13、Which is wrong among the following descriptions of Token Ring
A、Nodes in the token ring network form a closed ring structure through a network card and a point-to-point line
B、The data in the ring is transmitted around the ring station along one direction
C、The control of token ring is suitable for heavy load application
D、Token ring and token maintenance are complicated, and networking cost is high
14、Which is wrong among the following descriptions of the four major protocols of media access connection
A、IEEE 802.3 defines CSMA/CD bus access-control sublayer and physical layer
B、IEEE 802.11 defines the standard of access-control sublayer and physical layer for WLAN
C、IEEE 802.15 defines the standards of access-control sublayer and the physical layer for WAN
D、IEEE 802.16 define standards of access-control sublayer and physical layer for broadband wireless metropolitan-area network
15、Which is wrong among the following descriptions of "conflict detection"
A、Propagation delay is equal to D/V
B、The value of "conflict window" is equal to D/V
C、Within 2 times the propagation delay, the conflicting data frame can be propagated throughout the entire cable segment
D、All computers connected with the cable segment belong to one "collision domain"
16、Which is wrong among the following descriptions of the frame structure of Ethernet
A、The "type field" specified in the 802.3 corresponds to the "type/length field" of Ethernet V2.0 frames
B、No length field is set in DIX frames, and the receiving end can only determine the receiving state of a frame based on the interval between them
C、The minimum length of the data field is 64B and the maximum length is 1500B
D、The destination address of all 1 is the broadcast address, and the frame will be received by all nodes
17、Which is wrong among the following descriptions of IEEE802.1 Q protocol
A、IEEE 802.1 Q extends the Ethernet frame with the length and type fields in the frame head
B、TCI is divided into three parts: priority, CFI and VID
C、TPID value is 0x8100
D、VID value is between 1 and 4094
18、Which is wrong among the following descriptions of the main features of transparent bridges
A、The source node sending the frame is responsible for routing
B、It is a plug-and-play LAN interconnection device
C、Generating and maintaining that bridge forward table by self-learning algorithm
D、Bridge is transparent to the host
19、Among the following MAC protocols, the correct received data frame is confirmed by
A、CDMA
B、CSMA
C、CSMA/CD
D、CSMA/CA
20、Which is wrong among the following descriptions of IEEE802.11 WLAN
A、IEEE802.11 supports two basic structural units in the presence of base stations: BSS and ESS
B、An AP of a BSS is a base station with a diameter of less than 100m
C、Through the router, BSS composed of multiple APs can be interconnected to form an ESS
D、There is no base station in Ad hoc, and peer-to-peer communication is adopted between hosts
21、In a LAN with Shared media, the phenomenon of multi-node "conflict" is inevitable no matter what kind of media access control method is adopted.
22、One of the main features of switching lans is their low switching transmission latency.The delay time of LAN switch is higher than that of bridge, but lower than that of router.
23、Bridges can interconnect two networks using different data link layer protocols, different transmission media and different transmission rates.
24、Token Ring and Token Bus are used to determine the node access delay in the Ring, which is suitable for heavy load environment and supports priority service. Meanwhile, Ring maintenance is relatively simple.
25、Token Bus of IEEE802.4 and Token Ring network of 802.5 are only allowed to use single Token.
Unit homework
1、There are now multiple stations that need to share a 56kbps pure ALOHA channel.Each station outputs an average of one 100-bit frame per second (even if the previous frame has not yet been sent).How many stations are there at most when the idea is established?
2、Try to explain the meanings of "100", "BASE" and "T" in 100BASE-T.
3、How is CSMA/CD plugged into the shared channel?What are the advantages of doing this over traditional TDM?
4、Please explain the similarities and differences between Ethernet switches and bridges.
5、An office building has six floors, each with 12 adjacent offices.The front wall of each office contains a terminal socket that forms a rectangular grid on the vertical surface.It is known that there is a distance of 4 meters between the sockets in both horizontal and vertical directions.A direct cable can be pulled between any pair of adjacent sockets, whether in a horizontal or vertical direction. How many meters of cable are needed to connect all the sockets in the form of 802.3?
5 The Network Layer
5.1 Conception, functions and services随堂测验
1、When designing network layer services, we must ensure that they have nothing to do with routing technology.
2、Virtual circuit connection is not a fixed connection of physical lines, but a logical connection.
3、Datagram service is a connectionless service.
5.2 Routing algorithms随堂测验
1、Diffusion method and shortest path algorithm are static algorithms.
2、In a static algorithm, the network topology is static.
3、The spreading method has the problems of duplicate data packets and waste of bandwidth.
5.3 Distance Vector (D-V)随堂测验
1、In practice, the topology of the network does not change with time.
2、D vector is the distance from this node to all other nodes in the network.
3、Each node needs to update the routing table according to the path information.
5.4 Link State Algorithm (LSA)随堂测验
1、Link state algorithm includes topology distribution and local shortest path calculation.
2、Diffusion method has the problem of repeated arrival of state packets.
3、The limitation of the LSA is that it incurs significant communication and processing cost.
5.5 Congestion control and quality of service随堂测验
1、Insufficient buffer, slow processor speed and insufficient line bandwidth are all the causes of congestion.
2、The open-loop control method in congestion control can ensure that the problem will not appear at the beginning.
3、Admission control means that once congestion occurs, new virtual circuits are not allowed to be established until the problem is eliminated.
5.6 IP address, classification and subnet division随堂测验
1、The subnet mask uses the same format as IP addressing.
2、Hosts generally have one interface, but they can also have multiple interfaces.
3、IP addresses are used to bind interfaces, not hosts or routers.
Unit test
1、If both the destination network and the destination host are correct, but the IP packet is carrying TCP packets, and the destination host is using UDP protocol. Then, what type of ICMP packet will the destination host sends to the source host after dropping the packet
A、Network is unreachable
B、Host is unreachable
C、The protocol is unreachable
D、The port is unreachable
2、Which belongs to the global IP address among the followings
A、10.0. 0.1
B、155.25. 255.128
C、172.32. 0.1
D、192.168. 255.1
3、The broadcast address for network 155.25. 0.0/20 is
A、155.25. 0.255
B、155.25. 255.128
C、155.25. 15.255
D、155.25. 255.255
4、A company has an IP address of class A, and the original content has 700 subnets. Another 450 subnets are needed after the company is reorganized, and a maximum of 4092 hosts per subnet is required. What is the appropriate subnet mask
A、/16
B、/17
C、/18
D、/19
5、The IP address space of a network is 201.1.5.0/24, which is divided by subnet, and the address mask is 255.255.255.248. Then, the maximum number of subnets and the maximum number of addresses that can be allocated for each subnet of the network are
A、32, 8
B、32, 6
C、8, 32
D、8, 30
6、If the subnet mask is 255.255.192.0, which host with the following addresses must be routed to communicate with host 128.2.144.16
A、128.2. 191.33
B、128.2. 159.22
C、128.2. 192.160
D、128.2. 176.222
7、Routing table entries in a routing table include
A、The destination network and the full path to the network
B、The destination host and the full path to the destination host
C、The destination network and the IP address of the next-hop router to the destination network
D、The destination network and the MAC address of the next-hop router to the destination network
8、Which of the following situations requires sending an ARP request message
A、The host needs to receive data packets, but does not have the source IP address and MAC address of the packets
B、The host needs to receive data packets, but there is no record of packet source routing in the routing table
C、The host needs to receive data packets, but there is no destination host routing table entry in the routing table
D、The host needs to receive packets of data, but there is no MAC address corresponding to the packet destination IP address
9、The IP address block assigned by a company to the personnel department is 10.0.11.0/27, the IP address block assigned to the planning department is 10.0.11.32/27, and the IP address block assigned to the Marketing Department is 10.0.11.64/26. Then the addresses of these three address blocks after aggregation are
A、10.0. 11.0/25
B、10.0. 11.0/26
C、10.0. 11.64/25
D、10.0. 11.4/26
10、In the autonomous system using RIP protocol, if router R1 receives neighbor router R2 and sends it to the distance vector containing <net1,16>, then it can be concluded that
A、R2 can go through R1 to net1, 16 hops
B、R2 can go through R1 to net1, and the number of hops is 17
C、R1 can go through R2 to nuet1, and the number of hops is 17
D、R1 cannot go through R2 to net1
11、Which of the following protocols does not belong to the network layer
A、ICMP
B、IGMP
C、ARP
D、DHCP
12、The IP address space of a network is 201.1.5.0/24, which is divided by subnet, and the address mask is 255.255.255.248. Then, the maximum number of subnets and the maximum number of addresses that can be allocated for each subnet of the network are
A、32, 8
B、32, 6
C、8, 32
D、8, 30
13、If the subnet mask is 255.255.192.0, which host with the following addresses must be routed to communicate with host 128.2.144.16
A、128.2. 191.33
B、128.2. 159.22
C、128.2. 192.160
D、128.2. 176.222
14、A company has the IP address 201.12.77.0/24, among which 201.12.77.16/28 and 201.12.77.32/28 have been assigned to the personnel department and finance department. Now the technical department needs 100 IP addresses, and the addresses that can be assigned are
A、201.12.77.0/25
B、201.12. 77.48/25
C、201.12. 77.64/25
D、201.12. 77.128/25
15、R1 and R2 are two adjacent routers using RIP routing protocol in an autonomous system. The routing table of R1 is shown in figure (a). As shown in figure (b), R1 receives the (V, D) message sent by R2, and the distance of the four routing table items of R1 after the update is 0, 4, 4, and 2 from top to bottom. So the possible data among a, b, c, and d in figure (b) may be
A、1,2,2,1
B、2,2,3,1
C、3,3,3,1
D、4,4,3,2
16、Which is wrong among the following simplified representations of Ipv6 address FE : 30: 0: 0: 060: 0A00: 0: 09DC
A、FE:30:: 60: 0A00: 0: 09DC
B、FE:30: 60: A00: 0: 09DC
C、FE:30: 0: 0: 60: A00: 9DC
D、FE:3: 60: A: 0: 09DC
17、Which is right among the following expressions about UDP and TCP?
A、UDP gives the sequential delivery of data, whereas TCP does not give the sequential delivery of data
B、UDP does not allow multiplexing. TCP allows multiplexing
C、UDP runs the active flow control mechanism and TCP runs the passive flow control mechanism
D、UDP is connectionless and TCP is connection-oriented
18、In a TCP/IP network, what is the connection socket between two application processes?
A、IP addresses of both sides
B、The IP addresses and the port numbers of both parties
C、The port numbers of both parties
D、The MAC addresses and the port numbers of both parties
19、How many bytes is the data portion in TCP message segment?
A、65535
B、536
C、65495
D、65515
20、Given that the class B address of IP does not use 16 bits but 20 bits as the network number part of the class B address. How many networks of class B are available for assignment?
A、2 ^ 18
B、2 ^ 18-2
C、2 ^ 14-2
D、2 ^ 16
21、The application layer protocol of TCP/IP uses the client-server mode.
22、IP addresses can reflect geographic information about the location of the host.
23、RARP, IP and UDP are protocols belonging to the network layer.
24、BUS is a topology that can control media access only with CSMA/CD and not with tokens.
25、TCP connections are in the form of bitstreams that do not preserve the boundaries of data blocks.
Unit homework
1、There is a host on a 10Mbps network whose traffic is integer through a token bucket.The token bucket is filled at a rate of 1Mbps.The initial time token bucket was filled to a capacity of 10MB.How long can the computer transmit at a full rate of 6 Mbps?
2、Host A sent IP datagram to host B, passing through 7 routers on the way.How many times will ARP be used during IP datagram sending?
3、The hexadecimal value of an IP address is C02E2780. Convert it to the point decimal notation.
4、Suppose there are four companies that have applied for a large number of consecutive available IP addresses starting at 192.16.0.0.The four companies A, B, C and D will use 4000, 2000, 4000 and 8000 addresses in order.For each application, write down the first IP address assigned, the last IP address, and the mask in the form w.x.y.z /s.
5、The subnet mask for a network on the Internet is 255.255.248.0.How many mainframes can it accommodate?
6 The Transport layer
6.1 Introduction随堂测验
1、The core layer in the computer network architecture is _ _ _ _ _ _ _, whose main function is to realize distributed process communication.
A、Physical layer
B、Data link layer
C、Transport layer
D、Network layer
2、The mission of the transport layer is to provide reliable, cost-effective data transfer between the source and target machines, and to be completely independent of the physical network currently in use.
3、Like the data link layer, the two routers communicate directly over a physical channel.
4、Just as the network layer has two different types of services (connection-oriented and connectionless), there are two types of transport services, connection-oriented and connectionless.
5、Transport layer services are suitable for a variety of networks, but different services and qualities of service provided by different communication subnets need to be taken into account.
学习通是由中国科学技术大学、中国科学院计算技术研究所、上海交通大学、清华大学等多家高校共同开发建设的一个在线教育平台，旨在为全国广大学生、教师提供高质量的网络教育资源和服务。
信息通信网络
信息通信网络是一种基于物理网络和通信协议的新型网络，它支持多种数据传输模式和网络应用，为人们的日常生活、工作和学习提供了便利。信息通信网络的发展促进了人类社会信息化的进程。随着信息通信技术的进步和人们对数字化信息的需求增加，信息通信网络已成为现代社会的重要基础设施。
信息通信网络的组成
信息通信网络由三个部分组成：
- 物理网络：由电缆、光缆、无线信号传输设备等构成，用于将信息从发送端传输到接收端。
- 协议：用于控制数据传输的过程，包括数据格式、传输速度、数据传输的路线等。
- 应用：指基于信息通信网络的应用程序和服务，例如电子邮件、在线视频、远程教育等。
信息通信网络的类型
信息通信网络可以按照不同的方式分类，例如：
- 按照传输介质分类：可以分为有线网络和无线网络。
- 按照网络范围分类：可以分为局域网、城域网、广域网和互联网。
- 按照网络拓扑结构分类：可以分为星型网络、环形网络、总线网络和网状网络。
信息通信网络的应用
信息通信网络广泛应用于各行各业，它让人们在工作、学习和生活中得到了很多便利。
- 远程教育：学习通等在线教育平台的出现，让学习不受时间和空间的限制，人们可以随时随地学习。
- 电子商务：通过网络购物、在线支付等方式，方便快捷。
- 医疗卫生：通过远程诊断、远程手术等方式，可以为患者提供更好的医疗服务。
- 社交娱乐：社交网络、在线游戏、音乐、电影等各种娱乐形式，让人们在网络上找到更多的乐趣。
信息通信网络的发展
信息通信网络的发展正在以惊人的速度迎来新的历史时期，它的未来发展方向可以预见为：
- 更快的传输速度：新一代的信息通信网络将会采用更高效的传输技术和协议，使得数据传输的速度更快。
- 更智能的应用：随着人工智能技术的不断发展，网络应用将会变得更加智能化，能够更好地服务于人类。
- 更广泛的应用场景：信息通信网络将会进一步渗透到各个领域，包括工业、农业、交通等，为人们的生产和生活带来更多的便利。
总结
信息通信网络是现代社会的重要基础设施，它为人们的生产和生活带来了诸多便利。随着网络技术的不断发展，信息通信网络将会进一步发展壮大，为人类社会信息化的进程做出更大的贡献。
