The first 1 chapter summary
one , choice question
* The world's first computer network is （ A ）.
A. ARPANET B. ChinaNet C.Internet D.CERNET
* TCP/IP The network interface layer in the reference model corresponds to OSI Medium （ D ）.
A. network layer B. physical layer C. data link layer D. Physical layer and data link layer
* A computer network system in a building , belong to ( B ).
A. PAN B. LAN C. MAN D. WAN
* Service and agreement are two completely different concepts , The following statements about them are wrong ( D ).
A The agreement is horizontal , That is, a protocol is a rule that controls the communication between peer entities . The service is vertical , That is, the service is provided from the lower layer to the upper layer through the inter layer interface .
B. Under the control of the agreement , The communication between two peer-to-peer entities enables this layer to provide services to the upper layer . To implement this layer protocol , You also need to use the services provided by the following layer .
C. The implementation of the protocol ensures that services can be provided to the upper layer .
D. OSI The data units exchanged between layers are called protocol data units PDU.
* The standardization of LAN is made up of ( A ) To make it .
A. OSI B. IEEE C. ITU-T D. CCITT
* Internet The English abbreviation of service provider is ( D ).
A. DSS B. NII C. IIS D. ISP
* At present, the existing and used WAN are basically adopted ( C ).
A. Bus topology B. ring topology C. Mesh topology D. star topology
8. Among the following switching methods, the one with the best real-time performance is ( C )
A. Datagram mode B. Virtual circuit mode C. Circuit switching mode D. All methods are the same
9. stay OSI Reference model , The following statement is correct （ C ）
A. The connection between adjacent layers is carried out through protocol B. The connection between adjacent layers is carried out through conversation
C. The communication between peer layers is carried out through protocol D. The communication between peer layers is carried out through the interface
10. Rules established for data exchange in a computer network , A set of standards or conventions is called ( C )
A. Architecture B. Agreement elements C. Network protocol D. Functional specification
11． The following statement about network architecture is correct （C）.
A． The functions of each level are independent , Not related to each other
B． The communication between adjacent layer entities follows the same layer protocol rules
C． The communication between peer entities follows the same layer protocol rules
D． The communication between all levels in the hierarchical structure is logical communication
12．OSI/RM In the seven layer protocol of the reference model , The lower three floors are （D）.
A． Session layer , Bus layer , network layer
B． Presentation layer , Transport layer , physical layer
C． Logical layer , Sending layer , Receiving layer
D． physical layer , data link layer , network layer
13．Internet The core agreement is （B）.
14． stay OSI Reference model , The active elements in each layer are called （A）. It can be software , It can also be hardware .
A． entity B． Service access point C． Interface D． system
15． The three elements that describe network protocols are （B）
A． data format , code , signal level
B． grammar , semantics , synchronization
C． data format , control information , Speed matching
D． code , control information , synchronization
16． Wan and LAN are based on （A） To share .
A． Network scope B． Information exchange mode
C． Network users D． Network protocol
17． stay OSI In the model , Between the data link layer and the transport layer is （B）
A． physical layer B． network layer C． Session layer D． Presentation layer
18． stay OSI Reference model , The first N Layer and on it N＋1 The relationship between layers is （A）.
A．N Layer is N＋1 Service provided by layer
B．N＋1 Layers will be from N A header is added to the information received by the layer
C．N Layer utilization N＋1 Services provided by layer
D．N Layer pair N+1 Layers have no effect
19． About data exchange technology , The following statement is incorrect （C）.
A． Circuit switching connection oriented
B． Packet switching has better network response speed than message switching
C． Message exchange without storage and forwarding process
D． Packet switching has a store and forward process
20． The communication subnet provides the possibility of multiple transmission paths between the source node and the destination node of the network , Routing refers to （C）.
A． Establish and select a physical link B． Establish and select a logical link
C． After the network intermediate node receives a packet , Determine the path to forward packets
D． Select communication media
21． Network architecture is （D）.
A． Network layers and the collection of protocols in layers B． Network layer protocols and their specific descriptions
C． Network layer interface and its specific description D． Network layers , A collection of protocols in a layer and interfaces between layers
22． stay OSI Reference model , network layer , The data units transmitted by the data link layer and the physical layer are （C）.
A． message , frame , Bit B． grouping , message , Bit
C． grouping , frame , Bit D． Datagram , frame , Bit
23． The agreement is （D） Rules or conventions for communication between .
A． Upper and lower layers of the same node B． Different nodes
C． Adjacent entity D． Peer entities of different nodes
24． Among the three basic elements of network protocol ,（B） Is the structure or format of data and control information .
A． semantics B． grammar C． service D． morphology
25． Among the three basic elements of network protocol ,（A） It is the control information used for coordination and error handling .
A． semantics B． error control C． agreement D． Collaborative control
two , Completion
1． Computer network is a combination of computer technology and communications technology Combined products .
2． In network hierarchy ,n Layer is n-1 Layer users , again n+1 Service provider of layer .
3． Will cover a city , The computer network of one country or many countries is called wide area network , It only covers the same building , The computer network in the same university or within a few kilometers is called LAN
, The computer network between the two is called Metropolitan area network .
4． Computer networks can be divided into signal communication Subnet and resources Subnet .
5． Common computer network topologies are Bus type , Star type , Tree type , Ring type And reticular type 5 Topology .
6． In data exchange technology , Common switching technologies are Circuit switching , Message exchange and packet switching Three kinds .
7． stay OSI In the environment , The application process data of the sender is transmitted layer by layer from the application layer to the physical layer , The service data unit of the transport layer is called message , The service data unit of the network layer is called grouping
, The service data unit of the data link layer is called frame , The service data unit of the physical layer is called Bit .
8. Network protocols are usually designed with the idea of layering ,OSI Open system architecture divides protocols into 7 layer , and TCP/IP The architecture divides protocols into 4 layer .
9. The Internet can be divided into edge Partial sum core part . End system Located at the edge of the network , What works is So that many hosts can communicate with each other and exchange or share information .
At the core of the network , Its function is to press Store and forward Packet switching .
10. The communication mode adopted by the computer is customer - The server Mode and Peer to peer connection mode （P2P mode ）.
three , Judgment question
1． The computer network system belonging to packet switching network is composed of communication subnet and resource subnet . （）
30． Computer network is logically divided into communication subnet and resource subnet . The communication subnet is responsible for the information transmission of the whole network , The resource subnet is responsible for information processing , Provide available resources to the network . （）
38． The three elements that make up a network protocol are syntax , Semantics and synchronization . （）
48． Packet switching network uses store and forward to communicate . （）
four , Simple questions
13． Briefly describe what is the Internet and several types of network interconnection .（5 branch ）
answer ： Internet concept （2 branch ）, Three types LAN-LAN,LAN-WAN,WAN-WAN（3 branch ）
15．OSI/RM What levels are set ? What are the main functions of each layer ?（14 branch ）
answer ： physical layer ： Transparent transmission bitstream ;（2 branch ）
data link layer ： Error free transmission frame between adjacent nodes ;（2 branch ）
network layer ： Routing and congestion control between source and destination nodes ;（2 branch ）
Transport layer ： Reliable transmission of messages from end to end ;（2 branch ）
Session layer ： Session management and session synchronization ;（2 branch ）
Presentation layer ： Data format conversion , data encryption , Decryption, etc ;（2 branch ）
application layer ： Provide interface or means for users to use the network .（2 branch ）
16．OSI Differences and relationships between services and protocols in the reference model .
19． Brief customer / Server mode .
answer ： Communication between applications requires customer compliance - Server mode , The application layer protocols are based on this communication mode （1 branch ）. The server ： Means any provision （ Accessible through the network ） Service procedure （ Software ）. The server receives requests over the network , Then the service is provided and returned to the requester . If a computer is mainly used to execute a service program , The computer can also be called a server providing a service （3 branch ）. customer ： A program that sends a request to the server and waits for a response can be called a client .（1 branch ）
29．OSI Name and main functions of each layer of the reference model （ It can be described in one sentence ）.
answer ：( common 5 branch ) physical layer ： Transparent transmission bitstream ;
data link layer ： Error free transmission frame between adjacent nodes ;
network layer ： Routing and congestion control between source and destination nodes ;
Transport layer ： Reliable transmission from end to end ;
application layer ： Provide interface or means for users to use the network .
five , Comprehensive questions
6． Draw and explain TCP/IP The architecture of the protocol and the main functions of each layer , Describe the names and functions of the main protocols of each layer .（ common 17 branch ）
answer ：TCP/IP It is a group of protocol clusters , Not only include TCP agreement , It also contains many other agreements .TCP/IP And OSI Correspondence of seven layer reference model ： (4 branch )
Main functions of each layer ：
Network interface layer ： This layer receives IP The packet is encapsulated into a frame format suitable for transmission on the physical network and transmitted , Receive frame unpacking from physical network , formation IP grouping , Network interconnection layer processing (2 branch )
Network interconnection layer ： Responsible for communication between adjacent computers . Including routing , flow control , congestion control , error control (2 branch ).
Transport layer ： Ensure reliable end-to-end communication (2 branch ).
application layer ： The application layer includes many applications , Such as email , Remote login . strictly speaking , They don't belong to TCP/IP. however ,TCP/IP A number of agreements have been developed , People can develop their own applications .(2 branch )
Main agreement ：
ARP The protocol is the address translation protocol , It is responsible for IP The address is converted to the corresponding physical network address .(1 branch )
RARP Reverse address translation protocol , After site initialization , Only their own physical network address and no IP address , Then it sends a broadcast request through the protocol , Ask for your own IP Address can complete such function .(1 branch )
ICMP Used to check and report some basic errors . Give the reason for the error to a certain extent .(1 branch )
TCP（ Transmission control protocol ） Provide reliable for applications in an unreliable interconnection network , Connection oriented end-to-end byte stream data transmission service .(1 branch )
UDP（ User datagram protocol ） The information provided is unreliable , Connectionless datagram service , It is usually used in applications that do not require reliable transmission .(1 branch )