What is network decentralized optimization
Publish: 2021-04-12 05:43:38
1. Do you mean search engine optimization in websites?
search engine optimization (SEO) is a way to improve the ranking of target websites in relevant search engines by using the search rules of search engines. Many studies have found that users of search engines tend to pay attention to the first few items in the search results, so many websites hope to influence the ranking of search hits in various forms. Among them, the websites that rely on advertising for their living are the most. The so-called "optimizing the search engine" is to make the website easier to be accepted by the search engine. Deep understanding is: through SEO such a set of marketing ideas based on search engine, provide ecological self marketing solutions for the website, let the website occupy a leading position in the instry, so as to obtain brand income
to put it simply, it is to make use of technology and the sense of beauty to make user experience, so that people in need can find you more easily, from face to face, to let the website rank at the top of the search engine, for example, the website ranks at the first page of the network and Google's first page, which is the optimization of the website
there is also a kind of network engineering optimization:
it refers to making the network performance reach the best balance point we need through various hardware or software technologies! Hardware refers to the reasonable analysis of the system needs in terms of performance and price to make the optimal solution! Software refers to the setting of software parameters in order to achieve the highest performance load within the scope of the software
in short, it is to develop the configuration of the system to the best state, and reasonably allocate these configurations to achieve the best state
I don't know whether you asked these questions or not. Your question description is not clear.
search engine optimization (SEO) is a way to improve the ranking of target websites in relevant search engines by using the search rules of search engines. Many studies have found that users of search engines tend to pay attention to the first few items in the search results, so many websites hope to influence the ranking of search hits in various forms. Among them, the websites that rely on advertising for their living are the most. The so-called "optimizing the search engine" is to make the website easier to be accepted by the search engine. Deep understanding is: through SEO such a set of marketing ideas based on search engine, provide ecological self marketing solutions for the website, let the website occupy a leading position in the instry, so as to obtain brand income
to put it simply, it is to make use of technology and the sense of beauty to make user experience, so that people in need can find you more easily, from face to face, to let the website rank at the top of the search engine, for example, the website ranks at the first page of the network and Google's first page, which is the optimization of the website
there is also a kind of network engineering optimization:
it refers to making the network performance reach the best balance point we need through various hardware or software technologies! Hardware refers to the reasonable analysis of the system needs in terms of performance and price to make the optimal solution! Software refers to the setting of software parameters in order to achieve the highest performance load within the scope of the software
in short, it is to develop the configuration of the system to the best state, and reasonably allocate these configurations to achieve the best state
I don't know whether you asked these questions or not. Your question description is not clear.
2. It is the optimization of network data. Some programs and threads may not be necessary (such as uploading some files to the server in the background for analysis, networking for data detection, and so on). After optimization, it will prevent or limit their occupation of the network, and ensure the correct use of your network information, without affecting the download and download It is a kind of processing form that can be realized more quickly and conveniently. In short, the optimized network will ensure that your daily Internet access is faster, but it does not guarantee that your other programs will be affected
3. Through the ADSL dial-up Internet, has become the preferred way for many indivial users. Although this way of Internet access is much faster than the traditional telephone dial-up Internet access, this speed is still far from the real broadband speed. Of course, if we can use our brains to tap the potential of ADSL, there are still ways to make ADSL run faster, or even make its speed close to the real broadband speed. If you don't believe it, please take a look at the following ADSL optimization moves. I believe that under the guidance of these methods, the ADSL Internet speed is much faster than usual
1. Enable the data subcontracting function
as you all know, if you transmit large amount of data information on the Internet, you will find that the Internet speed of ADSL will be very slow at this time; On the contrary, if you transmit a small amount of data and information on the Internet, you will feel that the speed of ADSL becomes very fast. According to this principle, you can enable the data subcontracting function of ADSL, so that when ADSL transmits large capacity data information, it will automatically divide these data into small packets for transmission. In this way, you will not feel any interruption phenomenon when ADSL transmits data, so it will not take a long time to wait. To enable the data subcontracting function of ADSL, you can set it according to the following steps:
click the start / run command in turn. In the pop-up system running dialog box, enter the registry editing command regedit, and click OK to open the registry editing window of the system
select the registry branch HKEY in turn_ LOCAL_ MACHINE\ SYSTEM\ CurrentControlSet\ Services\ Tcpip\ Parameters. In the right sub window of the corresponding parameters branch, check whether the double byte value of sackopts is included. If not, you can right-click the parameters branch and execute the command "new / double byte value" from the pop-up right-click menu, and then name the newly created double byte value "sackopts"
then double-click the "sackopts" key value, enter the number "1" in the pop-up value setting window as shown in Figure 1, and then click the "OK" button. Finally, restart the computer system. In this way, ADSL installed in the computer can automatically start the data subcontracting function. At this time, when using ADSL to transmit large capacity data on the Internet, You will find that the speed of ADSL is much faster all of a sudden
2. Set the appropriate buffer size
generally, the size of the buffer accepted by the default data transmission unit of TCP / IP is 576 bytes. If the size of the buffer is set to be relatively large, once a TCP / IP packet data error occurs, all the packet contents in the whole data buffer will be changed, Will be lost and retransmitted; Obviously, continuously retransmission will greatly affect the efficiency of ADSL data transmission. Therefore, setting the appropriate buffer size to ensure that the efficiency of ADSL data transmission is always very high will have a direct impact on the ADSL transmission speed. When setting the buffer size, you can follow the following steps:
click the start / run command in turn. In the pop-up system operation dialog box, enter the registry edit command regedit, and click OK to open the registry edit window of the system
select the registry branch HKEY in turn_ LOCAL_ MACHINE\ SYSTEM\ CurrentControlSet\ Services\ VxD\ Mstcp, as shown in Figure 2
in the right sub window of the corresponding mstcp branch, check whether the string value "defaultrcvwindows" exists. If it does not exist, you can right-click the mstcp project and execute the "new / string value" command from the pop-up right-click menu, and take the name of the newly created string value as "defaultrcvwindows", Then double-click the "default rcvwindows" key value, and in the subsequent numerical setting window, enter the number "256960", and finally click the "OK" button, and then restart the computer system. At this time, ADSL's Internet access speed will be faster
3. Prevent frequent disconnection
if you use ADSL dial-up mode to access the Internet in Windows 98 system, it is particularly easy to connect and disconnect the network for a while. This phenomenon is mostly caused by the "congenital" poor compatibility of ADSL related network components in Windows 98 system; It is obvious that frequent disconnection will lead to a great decline in the speed of ADSL Internet access. In order to effectively improve the transmission speed of ADSL, you must find a way to prevent the frequent interruption of ADSL; To do this, it's very simple. You can go to ftp://61.155.52.131/adslpatch.EXE In this way, the compatibility of Windows 98 system with ADSL related network components will be improved, and it is not easy for ADSL to have frequent disconnection when accessing the Internet, In this way, ADSL's Internet speed will be improved
4. Dynamically optimize the MTU value
as we all know, the MTU value of TCP / IP has a direct impact on the data transmission efficiency of ADSL. If the value is set too large, it is necessary to re group the data in the actual transmission, which will rece the transmission efficiency. If the value is set too small, it is also not concive to the high-speed data transmission. Therefore, many people set the maximum MTU value of ADSL to 1450 by modifying the registry. In fact, the maximum MTU value of ADSL provided by different ISPs is not exactly the same. If you "fix" the maximum MTU value of ADSL to 1450, it may rece the data transmission efficiency of ADSL! So is there any way to automatically detect the line status provided by ISP in the process of ADSL dial-up Internet access, and dynamically optimize the MTU value according to the actual situation, so that the ADSL data transmission efficiency is always in the optimal state? The answer is yes. With the help of DSL speed tool, you can easily dynamically optimize the maximum MTU value of ADSL
from ftp://61.155.52.131/adslpatch.EXE The DSL speed tool is downloaded from and installed according to the conventional method; After the installation, double-click the corresponding shortcut program icon on the desktop, and then click "continue in trail mode" to open the optimization setting interface as shown in Figure 3
in the "normal optimize" tab page of the interface, first click the "testing your DSL connection speed online" button, and in the subsequent Internet page, Follow the prompts to detect your ADSL Internet speed. Once the detection is completed, you can see your ADSL Internet speed in the result page as shown in Figure 4
Figure 4
and then click the "process" button in Figure 3 interface. When the prompt window of "optimization takes effect after restarting the computer" appears on the screen, you must click the "OK" button to indicate approval
next, switch to the "advance optimize" tab page, and click the "start" button, so that DSL speed tool will start to detect the ISP environment parameters where your ADSL is located, and dynamically analyze and verify these parameters, so as to find the most ideal MTU value; After the analysis and verification operation, you can click the "process" button in the corresponding tab page, so that the DSL speed tool will automatically optimize ADSL dynamically with the most ideal MTU value. After the optimization, you must also restart the computer system. At this point, the task of dynamic optimization of MTU value is completed<
5. Overclocking ADSL
in order to tap the "potential" of ADSL devices as much as possible, you can overclock ADSL with the help of optimization tools such as ADSL overclocking marvel, so as to improve your surfing speed
when overclocking ADSL, You can start from http://www.skycn.com/soft/6021.html Download the latest version of ADSL overclocking Marvel program, and then install it into the computer system where ADSL is located; Then double click the corresponding program icon on the desktop to open the ADSL overclocking interface; Click the "advanced overclocking" tab in the interface to enter the overclocking advanced settings page as shown in Figure 5
Figure 5
next, click the "start verification" button on the page, and then ADSL overclock will automatically verify the current online parameters of ADSL, and dynamically modify the relevant parameters in the system registry. After verification, you can click the "advanced overclock" button, and ADSL overclock will officially overclock ADSL, After the overclocking task is completed, restart the computer system. When you use ADSL dial-up mode to access the Internet, you will find that the Internet speed is about twice as fast as before
6. Connect ADSL reasonably
don't underestimate the line connection of ADSL, because whether the line connection is appropriate or not has a great impact on the speed of ADSL Internet access. Because ADSL also uses a special twisted pair transmission technology to transmit data, and twisted pair is to wind two copper wires together with appropriate rules, so as to achieve the purpose of resisting external electromagnetic signal interference. For this reason, if you connect ADSL with the home telephone line, you must ensure that the home telephone line is not too long. After all, the two copper wires in the home telephone line are parallel. If their length is too long, it is easy to cause the decline of ADSL's ability to resist external interference, thus leading to the decline of ADSL's data transmission speed. Under normal circumstances, the home telephone line should not exceed 5 meters. If it is 5 meters away, it must be replaced with more than 5 types of twisted pair
in addition, ADSL transmits data by superimposing high frequency digital communication signal on the basis of ordinary telephone line; In order to ensure that the high-frequency digital signal is not interfered in the transmission process, please do not install the telephone before the ADSL filter, or install the telephone anti-theft system; Moreover, at each joint of ADSL connecting line, it is necessary to ensure that the joint is firm without any looseness, otherwise the data transmission speed will be greatly affected.
1. Enable the data subcontracting function
as you all know, if you transmit large amount of data information on the Internet, you will find that the Internet speed of ADSL will be very slow at this time; On the contrary, if you transmit a small amount of data and information on the Internet, you will feel that the speed of ADSL becomes very fast. According to this principle, you can enable the data subcontracting function of ADSL, so that when ADSL transmits large capacity data information, it will automatically divide these data into small packets for transmission. In this way, you will not feel any interruption phenomenon when ADSL transmits data, so it will not take a long time to wait. To enable the data subcontracting function of ADSL, you can set it according to the following steps:
click the start / run command in turn. In the pop-up system running dialog box, enter the registry editing command regedit, and click OK to open the registry editing window of the system
select the registry branch HKEY in turn_ LOCAL_ MACHINE\ SYSTEM\ CurrentControlSet\ Services\ Tcpip\ Parameters. In the right sub window of the corresponding parameters branch, check whether the double byte value of sackopts is included. If not, you can right-click the parameters branch and execute the command "new / double byte value" from the pop-up right-click menu, and then name the newly created double byte value "sackopts"
then double-click the "sackopts" key value, enter the number "1" in the pop-up value setting window as shown in Figure 1, and then click the "OK" button. Finally, restart the computer system. In this way, ADSL installed in the computer can automatically start the data subcontracting function. At this time, when using ADSL to transmit large capacity data on the Internet, You will find that the speed of ADSL is much faster all of a sudden
2. Set the appropriate buffer size
generally, the size of the buffer accepted by the default data transmission unit of TCP / IP is 576 bytes. If the size of the buffer is set to be relatively large, once a TCP / IP packet data error occurs, all the packet contents in the whole data buffer will be changed, Will be lost and retransmitted; Obviously, continuously retransmission will greatly affect the efficiency of ADSL data transmission. Therefore, setting the appropriate buffer size to ensure that the efficiency of ADSL data transmission is always very high will have a direct impact on the ADSL transmission speed. When setting the buffer size, you can follow the following steps:
click the start / run command in turn. In the pop-up system operation dialog box, enter the registry edit command regedit, and click OK to open the registry edit window of the system
select the registry branch HKEY in turn_ LOCAL_ MACHINE\ SYSTEM\ CurrentControlSet\ Services\ VxD\ Mstcp, as shown in Figure 2
in the right sub window of the corresponding mstcp branch, check whether the string value "defaultrcvwindows" exists. If it does not exist, you can right-click the mstcp project and execute the "new / string value" command from the pop-up right-click menu, and take the name of the newly created string value as "defaultrcvwindows", Then double-click the "default rcvwindows" key value, and in the subsequent numerical setting window, enter the number "256960", and finally click the "OK" button, and then restart the computer system. At this time, ADSL's Internet access speed will be faster
3. Prevent frequent disconnection
if you use ADSL dial-up mode to access the Internet in Windows 98 system, it is particularly easy to connect and disconnect the network for a while. This phenomenon is mostly caused by the "congenital" poor compatibility of ADSL related network components in Windows 98 system; It is obvious that frequent disconnection will lead to a great decline in the speed of ADSL Internet access. In order to effectively improve the transmission speed of ADSL, you must find a way to prevent the frequent interruption of ADSL; To do this, it's very simple. You can go to ftp://61.155.52.131/adslpatch.EXE In this way, the compatibility of Windows 98 system with ADSL related network components will be improved, and it is not easy for ADSL to have frequent disconnection when accessing the Internet, In this way, ADSL's Internet speed will be improved
4. Dynamically optimize the MTU value
as we all know, the MTU value of TCP / IP has a direct impact on the data transmission efficiency of ADSL. If the value is set too large, it is necessary to re group the data in the actual transmission, which will rece the transmission efficiency. If the value is set too small, it is also not concive to the high-speed data transmission. Therefore, many people set the maximum MTU value of ADSL to 1450 by modifying the registry. In fact, the maximum MTU value of ADSL provided by different ISPs is not exactly the same. If you "fix" the maximum MTU value of ADSL to 1450, it may rece the data transmission efficiency of ADSL! So is there any way to automatically detect the line status provided by ISP in the process of ADSL dial-up Internet access, and dynamically optimize the MTU value according to the actual situation, so that the ADSL data transmission efficiency is always in the optimal state? The answer is yes. With the help of DSL speed tool, you can easily dynamically optimize the maximum MTU value of ADSL
from ftp://61.155.52.131/adslpatch.EXE The DSL speed tool is downloaded from and installed according to the conventional method; After the installation, double-click the corresponding shortcut program icon on the desktop, and then click "continue in trail mode" to open the optimization setting interface as shown in Figure 3
in the "normal optimize" tab page of the interface, first click the "testing your DSL connection speed online" button, and in the subsequent Internet page, Follow the prompts to detect your ADSL Internet speed. Once the detection is completed, you can see your ADSL Internet speed in the result page as shown in Figure 4
Figure 4
and then click the "process" button in Figure 3 interface. When the prompt window of "optimization takes effect after restarting the computer" appears on the screen, you must click the "OK" button to indicate approval
next, switch to the "advance optimize" tab page, and click the "start" button, so that DSL speed tool will start to detect the ISP environment parameters where your ADSL is located, and dynamically analyze and verify these parameters, so as to find the most ideal MTU value; After the analysis and verification operation, you can click the "process" button in the corresponding tab page, so that the DSL speed tool will automatically optimize ADSL dynamically with the most ideal MTU value. After the optimization, you must also restart the computer system. At this point, the task of dynamic optimization of MTU value is completed<
5. Overclocking ADSL
in order to tap the "potential" of ADSL devices as much as possible, you can overclock ADSL with the help of optimization tools such as ADSL overclocking marvel, so as to improve your surfing speed
when overclocking ADSL, You can start from http://www.skycn.com/soft/6021.html Download the latest version of ADSL overclocking Marvel program, and then install it into the computer system where ADSL is located; Then double click the corresponding program icon on the desktop to open the ADSL overclocking interface; Click the "advanced overclocking" tab in the interface to enter the overclocking advanced settings page as shown in Figure 5
Figure 5
next, click the "start verification" button on the page, and then ADSL overclock will automatically verify the current online parameters of ADSL, and dynamically modify the relevant parameters in the system registry. After verification, you can click the "advanced overclock" button, and ADSL overclock will officially overclock ADSL, After the overclocking task is completed, restart the computer system. When you use ADSL dial-up mode to access the Internet, you will find that the Internet speed is about twice as fast as before
6. Connect ADSL reasonably
don't underestimate the line connection of ADSL, because whether the line connection is appropriate or not has a great impact on the speed of ADSL Internet access. Because ADSL also uses a special twisted pair transmission technology to transmit data, and twisted pair is to wind two copper wires together with appropriate rules, so as to achieve the purpose of resisting external electromagnetic signal interference. For this reason, if you connect ADSL with the home telephone line, you must ensure that the home telephone line is not too long. After all, the two copper wires in the home telephone line are parallel. If their length is too long, it is easy to cause the decline of ADSL's ability to resist external interference, thus leading to the decline of ADSL's data transmission speed. Under normal circumstances, the home telephone line should not exceed 5 meters. If it is 5 meters away, it must be replaced with more than 5 types of twisted pair
in addition, ADSL transmits data by superimposing high frequency digital communication signal on the basis of ordinary telephone line; In order to ensure that the high-frequency digital signal is not interfered in the transmission process, please do not install the telephone before the ADSL filter, or install the telephone anti-theft system; Moreover, at each joint of ADSL connecting line, it is necessary to ensure that the joint is firm without any looseness, otherwise the data transmission speed will be greatly affected.
4. What does network optimization mainly do? SEO job responsibilities:
1. Keyword analysis. The construction of a website is not to build a website at the beginning, but you need to have an idea first. This is actually the positioning of a website keyword. Of course, this positioning should be considered from multiple perspectives, and the conclusion should be made according to your procts, and a lot of vocabulary analysis, opponent analysis, keyword layout, etc
2. Website structure analysis. The construction of the website is to allow the network (for example, the network) spider to crawl, of course, your website should have a structure in line with it, and you need to understand the design of the website, the language of the website is best div + CSS style, general website is to achieve directory structure
3. After the website is built, comprehensive analysis shows that after a website is built, we should first fill in the articles and content, because the website is just built, so don't let the website appear dead chain, regularly update the articles quickly, and slowly make good use of webmaster tools to analyze the website, and want the major search engines to submit.
1. Keyword analysis. The construction of a website is not to build a website at the beginning, but you need to have an idea first. This is actually the positioning of a website keyword. Of course, this positioning should be considered from multiple perspectives, and the conclusion should be made according to your procts, and a lot of vocabulary analysis, opponent analysis, keyword layout, etc
2. Website structure analysis. The construction of the website is to allow the network (for example, the network) spider to crawl, of course, your website should have a structure in line with it, and you need to understand the design of the website, the language of the website is best div + CSS style, general website is to achieve directory structure
3. After the website is built, comprehensive analysis shows that after a website is built, we should first fill in the articles and content, because the website is just built, so don't let the website appear dead chain, regularly update the articles quickly, and slowly make good use of webmaster tools to analyze the website, and want the major search engines to submit.
5. That is, according to the rules of search engines, such as the Internet and Google, they extract information, and build websites in the way that most meets their requirements, so as to achieve the effect that the website can be displayed on the front page of the search engine. To put it simply, let others search for a word, your website can appear in front of his eyes, and is the front.
6. 1. When the mobile communication network is completed, the function of network optimization is to ensure the full coverage of the network and the reasonable allocation of network resources. In the initial stage of the network, it is mainly responsible for the full coverage of the signal. After the network is basically formed, with the increase of BTS in the network, the interaction between BTS will be more and more serious. At the same time, with the increasing number of customers, the demand for the reasonable allocation of network resources will be higher and higher. The main work of the network optimization engineer will become to eliminate the mutual interference between BTS in the network, the allocation of resources and the further planning and construction of the network
2. Performance analysis. Due to the increasing number of customers in the network, network resources will graally change from idle to congestion. The uneven distribution of customer density will also lead to the use of network resources can not be the same as the model in the early stage of planning. In this case, performance analysis is needed. Engineers need to analyze the traffic in the network to reasonably allocate the resources in the network. At the same time, according to the overall resource utilization rate of the network and the change of network traffic, they need to put forward the further network construction scheme
3. Road test. Although the number of base stations in the network is small in the initial stage of network construction, and the connection between base stations is basically in a rather fixed state, with the increasing number of base stations in the network, there will be many covered base stations in the same section of the road. Whether users can occupy the most suitable base station for communication will directly affect the quality of users' calls, The main task of the road test engineer is to ensure that the user can use the best base station signal to make a call on the road.
2. Performance analysis. Due to the increasing number of customers in the network, network resources will graally change from idle to congestion. The uneven distribution of customer density will also lead to the use of network resources can not be the same as the model in the early stage of planning. In this case, performance analysis is needed. Engineers need to analyze the traffic in the network to reasonably allocate the resources in the network. At the same time, according to the overall resource utilization rate of the network and the change of network traffic, they need to put forward the further network construction scheme
3. Road test. Although the number of base stations in the network is small in the initial stage of network construction, and the connection between base stations is basically in a rather fixed state, with the increasing number of base stations in the network, there will be many covered base stations in the same section of the road. Whether users can occupy the most suitable base station for communication will directly affect the quality of users' calls, The main task of the road test engineer is to ensure that the user can use the best base station signal to make a call on the road.
7.
It mainly includes three categories: network resource manager, application performance accelerator and web performance accelerator< br />
8. The theory of computer network studies the typical problems and their solutions in the process of computer network planning, design, implementation, testing, operation, application, maintenance and management. It is a comprehensive applied science, in addition to the direct use of communication theory and technology, computer science and technology, but also involves logic, operations research, statistics, model theory, graph theory, information theory, cybernetics, simulation, artificial intelligence, cognitive science, neural networks and other disciplines<
optimization design
editor
in view of the huge scale, wide contact and many factors involved in the computer network, it is usually divided into various specific problems, highlighting the main factors, ignoring or weakening the secondary factors, summarizing and abstracting, and establishing a typical model to study
the first specific and theoretical problems to be solved when building a computer network. The purpose is to design and build a safe, reliable, effective, well operated, adaptable, easy to manage, easy to maintain, easy to transform and easy to expand computer network with the least investment (including manpower, material resources, financial resources, time, etc.) under the condition of meeting the application requirements and objective constraints, It is expected to answer the questions about the time limit of fund recovery and the maximum social and economic benefits that may be obtained. The optimization design is divided into three stages: 1) requirement analysis and planning stage. The demand and environment should be investigated, and the necessary information and data should be collected and sorted out, including application purpose, information format, communication volume, response time, error rate, reliability requirements, selection standards, existing equipment, user distribution, geographical environment, natural conditions, meteorological characteristics, external influence, etc. The purpose is to identify the demand, find out the key links, and provide reference for the development of the project Plan the overall outline of the project. ② Network overall design stage. On the basis of investigation and analysis, the overall framework and important network parameters of the network should be determined according to the application requirements, and some important key issues must be selected, such as the selection of topology, the selection, placement and connection method of equipment, the selection of communication medium, line layout and capacity allocation, communication proceres, routing, flow and error control technology, The types of network services, the quality of service and the choice of high-level protocols. ③ Design scheme evaluation stage. According to the evaluation target. Various mathematical models (such as prediction model, optimization model, performance evaluation model, etc.) are established to analyze and evaluate the network performance, cost, time limit of construction period, benefit budget estimate, fund recovery period, etc., and give technical and economic feasibility conclusions. If the conclusion fails to meet the expected requirements, some or all of them should be redesigned according to the situation<
network architecture
Edit
computer network architecture is a set of principles and basis for planning, designing and establishing computer network, including hierarchy, function division, protocol specification, process description, etc. The most influential network architecture for the development of computer network is the open systems interconnection (OSI) reference model proposed by the international organization for Standardization (ISO). It is formulated and described through three abstract levels: system model, service definition and protocol specification. Architecture model is the highest level abstraction of OSI. It constructs an abstract and hierarchical architecture model from the functional and conceptual level, and describes the overall performance, structural elements, behavior characteristics, hierarchical relationship, data format and other contents of open system. The OSI architecture model consists of application layer, presentation layer, session layer, transport layer, network layer, data link layer and physical layer. Service definition is a low-level abstraction of OSI. It defines the services provided by each layer in more detail, and specifies the external features and abstract interfaces of each layer, but it does not involve the details of whether or not to implement and how to implement. Protocol specification is the lowest level abstraction of OSI. It precisely defines the semantics and syntax of the control information that a layer of entities need to transmit in order to work together and interact with each other, and what kind of proceres are used to analyze, interpret and process them. The further development trend of architecture model is to study and formulate network application architecture model, which aims to create a good operating environment and development environment for network users. For example, some network experts put forward the idea of open application architecture (OAA) model based on OSI model. OAA consists of operating environment and development and maintenance environment<
Path Selection
editing
there are several hot research topics in the early computer field, with many achievements and large amount of literature. The main purpose of path selection is to select the best path in the network and transmit the message information sent by the source site to the destination site in a high-speed and effective way. Its focus is to improve the network service quality, rece the delay time and rece the transmission cost. The criteria to measure the quality of path selection algorithm include: 1) the message is sent to the destination in the shortest time, the shortest path or the least cost. ② The algorithm is simple, easy to implement and has strong adaptability (it can adapt to the impact of network faults and structural changes). ③ However, it increases the network and node overhead (including processor time, storage capacity, information transmission, etc.). ④ It helps to improve network performance, maintain stable throughput, rece average transmission delay, balance network load and so on. Typical path selection algorithms include diffusion path selection, random path selection, fixed path selection, adaptive path selection, etc<
control content
Edit
flow control and congestion control
the purpose of flow control and congestion control is to control the flow of information on the network and each communication line, and keep the network in a stable working state, so as to improve the network throughput and rece the average delay time. Its focus is to improve the network efficiency and resource utilization, Prevent congestion and deadlock. Flow control can be divided into four types: flow control between adjacent nodes, flow control between source node and destination node, flow control between host and node, flow control between host and host. The common control methods include limiting transmission rate, rejecting retransmission, suspending transmission, limiting the size of receiving and sending window, reserving buffer, etc. The methods used for congestion control include reservation of buffer, restriction of pipeline flow, access permit, reverse suppression, etc
error control
is also an important research topic in network design. Its purpose is to select the appropriate control mechanism and method according to the application requirements, line quality, equipment performance and external environment, find out and correct the errors in information transmission, and rece them to the allowable level. In computer network, two basic strategies are usually used to deal with errors in information transmission: ① using error correcting codes. That is, enough rendant information is added to the message to be sent, so that the receiver can not only find out, but also correct the errors in the message. Because of the large amount of information rendancy and complex control, it is usually used for one-way transmission or as an auxiliary measure. ② Use error detection code. In other words, some rendant information is added to the message to be sent, so that the receiver can find out the error in the message (but do not know what kind of error), and inform the sender to retransmit the original message. Communication protocol and network protocol usually adopt this method<
protocol engineering
editing
one of the most active research topics in the field of computer network, the purpose is to apply the principles and methods of software engineering to the description, implementation and verification of computer network protocols. The main research contents of protocol engineering include three aspects: (1) protocol formal description and its formal description language. ② Automatic generation technology of protocol software and its development and maintenance tool. ③ Protocol conformance testing technology and testing tools. The research of protocol engineering is helpful to deepen the understanding of computer network protocol, improve the proction efficiency of protocol software, and improve the maintenance and management level of network protocol software. However, compared with software engineering, protocol engineering has a long way to go in terms of the depth and breadth of research, development and application.
optimization design
editor
in view of the huge scale, wide contact and many factors involved in the computer network, it is usually divided into various specific problems, highlighting the main factors, ignoring or weakening the secondary factors, summarizing and abstracting, and establishing a typical model to study
the first specific and theoretical problems to be solved when building a computer network. The purpose is to design and build a safe, reliable, effective, well operated, adaptable, easy to manage, easy to maintain, easy to transform and easy to expand computer network with the least investment (including manpower, material resources, financial resources, time, etc.) under the condition of meeting the application requirements and objective constraints, It is expected to answer the questions about the time limit of fund recovery and the maximum social and economic benefits that may be obtained. The optimization design is divided into three stages: 1) requirement analysis and planning stage. The demand and environment should be investigated, and the necessary information and data should be collected and sorted out, including application purpose, information format, communication volume, response time, error rate, reliability requirements, selection standards, existing equipment, user distribution, geographical environment, natural conditions, meteorological characteristics, external influence, etc. The purpose is to identify the demand, find out the key links, and provide reference for the development of the project Plan the overall outline of the project. ② Network overall design stage. On the basis of investigation and analysis, the overall framework and important network parameters of the network should be determined according to the application requirements, and some important key issues must be selected, such as the selection of topology, the selection, placement and connection method of equipment, the selection of communication medium, line layout and capacity allocation, communication proceres, routing, flow and error control technology, The types of network services, the quality of service and the choice of high-level protocols. ③ Design scheme evaluation stage. According to the evaluation target. Various mathematical models (such as prediction model, optimization model, performance evaluation model, etc.) are established to analyze and evaluate the network performance, cost, time limit of construction period, benefit budget estimate, fund recovery period, etc., and give technical and economic feasibility conclusions. If the conclusion fails to meet the expected requirements, some or all of them should be redesigned according to the situation<
network architecture
Edit
computer network architecture is a set of principles and basis for planning, designing and establishing computer network, including hierarchy, function division, protocol specification, process description, etc. The most influential network architecture for the development of computer network is the open systems interconnection (OSI) reference model proposed by the international organization for Standardization (ISO). It is formulated and described through three abstract levels: system model, service definition and protocol specification. Architecture model is the highest level abstraction of OSI. It constructs an abstract and hierarchical architecture model from the functional and conceptual level, and describes the overall performance, structural elements, behavior characteristics, hierarchical relationship, data format and other contents of open system. The OSI architecture model consists of application layer, presentation layer, session layer, transport layer, network layer, data link layer and physical layer. Service definition is a low-level abstraction of OSI. It defines the services provided by each layer in more detail, and specifies the external features and abstract interfaces of each layer, but it does not involve the details of whether or not to implement and how to implement. Protocol specification is the lowest level abstraction of OSI. It precisely defines the semantics and syntax of the control information that a layer of entities need to transmit in order to work together and interact with each other, and what kind of proceres are used to analyze, interpret and process them. The further development trend of architecture model is to study and formulate network application architecture model, which aims to create a good operating environment and development environment for network users. For example, some network experts put forward the idea of open application architecture (OAA) model based on OSI model. OAA consists of operating environment and development and maintenance environment<
Path Selection
editing
there are several hot research topics in the early computer field, with many achievements and large amount of literature. The main purpose of path selection is to select the best path in the network and transmit the message information sent by the source site to the destination site in a high-speed and effective way. Its focus is to improve the network service quality, rece the delay time and rece the transmission cost. The criteria to measure the quality of path selection algorithm include: 1) the message is sent to the destination in the shortest time, the shortest path or the least cost. ② The algorithm is simple, easy to implement and has strong adaptability (it can adapt to the impact of network faults and structural changes). ③ However, it increases the network and node overhead (including processor time, storage capacity, information transmission, etc.). ④ It helps to improve network performance, maintain stable throughput, rece average transmission delay, balance network load and so on. Typical path selection algorithms include diffusion path selection, random path selection, fixed path selection, adaptive path selection, etc<
control content
Edit
flow control and congestion control
the purpose of flow control and congestion control is to control the flow of information on the network and each communication line, and keep the network in a stable working state, so as to improve the network throughput and rece the average delay time. Its focus is to improve the network efficiency and resource utilization, Prevent congestion and deadlock. Flow control can be divided into four types: flow control between adjacent nodes, flow control between source node and destination node, flow control between host and node, flow control between host and host. The common control methods include limiting transmission rate, rejecting retransmission, suspending transmission, limiting the size of receiving and sending window, reserving buffer, etc. The methods used for congestion control include reservation of buffer, restriction of pipeline flow, access permit, reverse suppression, etc
error control
is also an important research topic in network design. Its purpose is to select the appropriate control mechanism and method according to the application requirements, line quality, equipment performance and external environment, find out and correct the errors in information transmission, and rece them to the allowable level. In computer network, two basic strategies are usually used to deal with errors in information transmission: ① using error correcting codes. That is, enough rendant information is added to the message to be sent, so that the receiver can not only find out, but also correct the errors in the message. Because of the large amount of information rendancy and complex control, it is usually used for one-way transmission or as an auxiliary measure. ② Use error detection code. In other words, some rendant information is added to the message to be sent, so that the receiver can find out the error in the message (but do not know what kind of error), and inform the sender to retransmit the original message. Communication protocol and network protocol usually adopt this method<
protocol engineering
editing
one of the most active research topics in the field of computer network, the purpose is to apply the principles and methods of software engineering to the description, implementation and verification of computer network protocols. The main research contents of protocol engineering include three aspects: (1) protocol formal description and its formal description language. ② Automatic generation technology of protocol software and its development and maintenance tool. ③ Protocol conformance testing technology and testing tools. The research of protocol engineering is helpful to deepen the understanding of computer network protocol, improve the proction efficiency of protocol software, and improve the maintenance and management level of network protocol software. However, compared with software engineering, protocol engineering has a long way to go in terms of the depth and breadth of research, development and application.
Hot content