ginger snaps jewelry wholesale Briefly introduce the four Internet networks in my country?

wholesale turquoise fashion jewelry The following content will help the issues raised by the landlord:
1. China ’s national information
The method of mentioning the method of national information infrastructure has no national information infrastructure, which is the idea of ​​national informatization. China's national informatization is under the unified planning and organization of the country. It applies modern information technology in all aspects of agriculture, industry, science and technology, national defense and social life, in -depth development and wide use of information resources, and accelerating the country's modernization process.

The goal of national information construction is: by 2000, a certain scale and relatively complete national information system will be formed; by 20L0, a sound, quite large scale, advanced one will be established National informationization system. The national information system consists of the following six elements, namely information resources, national information networks, information technology applications, information technology and industries, information talents, information policies and standards and standards.

It can be seen that my country's informatization is different from foreign information highways and national information infrastructure. my country emphasizes the close relationship between the six elements of the information system, and places the development and utilization of information resources in the core position. In recent years, the development speed of China's information industry has exceeded the growth rate of the national economy. During the eighth and fifth, the average annual increase in the electronics industry was increased by 30%, and the average increase in the telecommunications industry was more than 40%. China Communications Network basically realizes digitalization and programming. The nation ’s initially built -in optical cables, supplemented by digital microwave and satellite communication, and various means.

L at the end of 1993, the relevant ministries of the country decided to build the "Golden Bridge", "Golden Card", and "Gold Guan" project, referred to as the "three gold" project. The "Golden Bridge" project is based on the satellite comprehensive digital network. It forms an open space integrated network structure based on optical fiber, microwave, and wireless movement. The National Public Economic Information Communication Network with engineering connectors can transmit data, words, images, etc., and use emails, electronic data exchange (EDI) as information exchange platforms to provide physical channels for circulation of various types of information. At present, Jinqiao Engineering has established a satellite comprehensive information network with satellite communication with satellite communications in 24 central cities such as Beijing, Tianjin, Shenyang, Dalian, Changchun, Harbin, and Shanghai with satellite communication.

"Gold Card", the project is the electronic currency project. Its goal is to promote and popularize financial trading cards and credit cards in the 300 million cities in more than 10 years. The "Guan Guan" project uses EDI to realize international trade informatization and further connect with international trade.

At present, 114 information centers (commissions, offices) are established, and 50%have established computer networks, of which 15%have established computer networks covering the country; provincial (city, district) establishment established 32 and 40%of the information centers were established, of which L0%established computer networks covering the province (city, district); 1,000 large state -owned enterprises established their own information centers and 50%established corporate computer networks. The ratio of these networks and public networks is lower than L0%. From the perspective of Inteiwet's domestic development, as of June 1999, the four Internet Internet achieved interconnection. Among them, there are more than 4 million users, more than 1,600 access units, more than 150,000 computers, and 12,643 registered three -level domain names registered under CN. It is foreseeable that in 2000, the installed capacity of Chinese computers will exceed L00 million, of which 30%will be connected to various computer networks and mainly based on public computer networks. At the same time, with the establishment of the high -speed Internet network exchange center and regional exchange center, it will greatly promote the information sharing of the Internet. By 20L0, my country ’s computer networks will be more than L00,000, 30%of families can get network services, and a variety of information media integrate networks will make significant progress.

2. China Public Data Network

In recent years, China's public data communication network has built rapidly. The telecommunications department has established digital communication networks such as ChinaPac, Chinaddn, and Chianfrn, forming my country's public data communication network. rnrn中国公用分组交换数据网(ChinaPAC) rnrnl993年9月开通，l996年底已经覆盖全国县以上城市和一部分发达地区的乡镇，与世界23个国家Interconnect with 44 data networks in the region.

(1) Network condition

The group exchange network is the earliest basic data communication network construction and development of the post and telecommunications department. The group exchange network is based on CITTX.25 recommendations, which can meet the communication between different rates, different models of terminals and computers, computers and computers, and computer local area networks. The group exchange network is a basic data communication network that can build various value -added services on its network platform, such as: electronic mailboxes, electronic data exchange, fax storage forwarding, etc.

chinaPac consists of the national backbone network and the province (cities, districts) of the provinces (cities, districts). At present, the backbone network covers all provincial capital cities, and the provincial network covers all cities and developed towns with business requirements. By interconnected with the telephone network, ChinaAPAC can cover all areas where telephone networks have reached. CHINAPAC has a first-level exchange center and a secondary exchange center. The first-level exchange center adopts an incomplete mesh structure. In the entrance and exit of Guangzhou, there is an entrance to the Hong Kong and Macau regions to complete the network of international data.

(2) network characteristics and business functions

The prominent advantage of the packet exchange network can be opened on one physical circuit at the same time, and use it at the same time for multiple users to use simultaneously. ; The network has a dynamic path and complex and complete error correction function. The X.25 protocol was developed under the poor quality of the physical link transmission. In order to ensure the reliability of data transmission, she must perform error testing and error transmission on each link; this complicated error is Although the verification mechanism has limited its transmission efficiency, it does provide a good guarantee for the secure transmission of user data.

chinapac provided as follows:

L. Basic business functions

Basic business functions are the basic business provided by any digital terminal device (DTE) Function. It can meet the basic requirements of users' communication. There are two types of basic businesses, exchanged virtual circuits (SVC); permanent virtual circuit (PVC)

2. Optional business function

Special needs of users, special business functions provided by users, such as calls, calls, blocked blocking, one -way logical channels, one -way logical channels, etc.

3. Other business functions

chinaNe also provided other costs of ITU-T recommended business functions, such as virtual special network (VPN), TCP/IP, grouping multi-site broadcast, calling, calling Change to wait.

(3) User access method

chinaNenet provides two access methods.

1. Special line method

The application for large communication business, frequent use of frequent, high reliability, and no loss of loss, but the dedicated line is required, and the cost is relatively high. The network access rate is 9.6 to 64kbps.

2. Telephone dialing

The applications for small business volume, long interval time, and tolerating the application of failure. Because of its existing telephone lines, there is no need to invest, and the data can be shared with the words, so it greatly saves investment and is an ideal access method for scattered users. It can be divided into X.28 asynchronous dial-up access or X.32 synchronous dial-up network. The speed of dial-up access to the network is L200-9600bps

(4) Tariff policy
nChinaPac The one is the time -to -measure charging, and the other is the monthly charging. Time measurement charges.

The application field and business positioning wide

compared with DDN and frame relay, and the group business tariffs are cheaper. Essence In the case of a multi -point connection at the same time, the dotted circuit function of the group exchange network can replace the expensive multi -point DDN dedicated line. However, due to the complexity of the X.25 protocol itself, the group business is used in low -speed applications with a rate of less than 64K. For example, with the continuous advancement of the Gold Card project, the use of POS machines is becoming more and more popular, and the POS business volume is small, but the real -time requirements are high. Essence

The public digital data network (Chinadd)

digital communication network (DDN) is to provide permanent and semi -permanent connection lines using digital channels to transmit data signals as the mainstay Digital transmission network. It can provide a variety of flexible data interfaces for transmitting data signal services. Due to its simple protocol and high rate, it has developed rapidly in my country in recent years.

DDN consists of digital channels, DDN nodes, network management systems, and user ring circuits. It mainly provides digital -specific line services with points and points to multiple points. G3 fax business.

DDN's main features are:

(1) High transmission quality. Due to the current DDN use of a large number of fiber transmission channels, the transmission quality is greatly improved;

(2) The transmission rate is high, the rate is between 2400bps and 2Mbps

(3) The protocol is simple. Because DDN mainly adopts time reuse and cross -connection technology, the user information is transparent. There are fewer technical requirements for users and flexible applications;

(4) In the DDN network, advanced network management technology is adopted, line scheduling and fault monitoring can achieve centralized management. The automatic route roundabout improves the utilization rate of user lines.
(1) The business application and characteristics of DDN

DDN mainly provides point -to -point digital special line services. Widely used in the fields of banking, securities, meteorology, cultural education, etc., used in the interconnection of LAN7WAN, and the interconnection of different networks. For example, a company's headquarters and divisions are located in different locations, and the communication between two points is very frequent. Not only must it be connected to the phone, but also the computer connected to the Internet. If a DDN dedicated line is rented, and the reuse equipment is added at both ends to connect the telephone system distributed between the two places and the computer system, it can easily communicate between the two places. This not only saves the long -distance telephone costs between the two places, but also achieves the interconnection of the computer system.

DDN also provides multi -point business, mainly refers to the multi -point business, two -way multi -point business (rotation) and conference TV business. Broadcasting multi -point business features are: data information flow can be transmitted from one point to multiple points, so that multiple points can get the same information at the same time. Multi -point broadcasting business is suitable for information promulgation (stock, news, meteorological forecast, etc.). The two -way and multi -point business mainly refers to a two -way communication with one at a time at a time, and the main station regularly accesss a slave station and exchange information with the Site. The two -way multi -point communication business is suitable for centralized surveillance, credit card verification, data services, and pre -system. The television business of the conference is to use DDN's multi -point bridge connection function to achieve the focus of multi -point i, secret image, and words. Each site of the conference TV system can communicate with other sites as the main site, but only one main station can be at a time. One feature of the multi -point business is that a certain point can complete the communication between the multi -point through one interface, saving user -end equipment and network resources, and reduced investment. In addition, the use of DDN online relay resource modules and voice compression modules can also achieve open frame relay business and compressed voice/G3 fax business.

(2) The history, current status and development of Chinaddn

The public data network is a data network operated by the post and telecommunications department and provided services to users nationwide. In the early 1990s, first developed in several cities, and in 1994, the CHINDDN first -level trunk network was formed. At present, the first -level trunk network has reached all provincial capital cities, and all provinces, municipalities, and autonomous regions are actively building and operating DDN networks. By the end indivual. In the near future, it can provide users with a nationwide virtual special network (VPN) business.

chinaddn is divided into the first -level trunk network, secondary trunk network, and local network level according to the responsible geographical area of ​​the network construction, operation, management and maintenance of the network. The first -level trunk network is composed of nodes set up in various provinces, autonomous regions and municipalities. It mainly provides a transit of cross -provincial long -distance DDN business. At present, it has been connected to all provincial cities except Taiwan. The secondary trunk network is composed of nodes set in the province, which provides DDN business in the province's long -distance and entry and exit provinces. Except for Tibetan provinces, the province has been completed. The local network refers to the network within the city, which mainly provides users with local and long -distance DDN services.

At present, Chinddn has become a supporting network of other networks of the post and telecommunications department. A large number of Chinddn, Chinafax, and ChinaNet are on the chinaddn. CHINADDN, as a transmission plane of the first phase of the Telephone No. 7 Salmonic Network, will play an important role in the construction of the telephone network. The DCN project of the network management center and the provincial network management center also chose ChinaDDN as its transmission channel. Mobile phone letters to allow roaming and multimedia networks to rely on Chianddn to transmit information. The China Financial Data Network formed by the Ministry of Posts and Telecommunications and the Chinese people's silver is a huge frame relay network, all of which use CHIANDDN as data transmission channels. Chinaddn is increasingly becoming an important support for various businesses of telecommunications.

It, all sectors of society also rent the CHINDDN dedicated line to carry out its own business. Various professional banks, securities companies, and education and research departments are the user base of ChinaDDN.

CDCHINADD's user access method

The media that connects users and DDN business providers (telecommunications bureau) is mainly telephone copper lines, so users access to chinaddn mainly use Modem, The number of words and the 2B D line terminal device are connected by telephone copper line. With the user's high -speed requirements, HDSL device will also be applied in the network.

CinaFrn

Chinafrn is the first broadband data for the public to provide services to the public in my country The communication network will have a positive impact on my country's national economic informatization and will become an important part of my country's information highway.

chinafrn mainly provides medium and high -speed data communication services above 64K. The business type can be either sudden or real -time.

chinafrn can also provide high -speed relay transmission for other data communication networks, which enhances the performance of each network and improves the use efficiency of the line.

The main feature of China's public frame relay business backbone network is the ATM technology platform, while providing frame relay and Xinyuan relay and other businesses. The main technical characteristics of the backbone network of China's public frames, including

(L) the device is advanced, the network is good, and the backbone hub adopts a full network connection.

(2) The type of network business is complete, providing basic businesses such as relay PVC, ATMPVC, and SVC.

(3) The port type is complete and the range is wide. For frame relay business, the types of interfaces provided by the network include V35, X.21, EL, Channel EL, ISDNPRI, E3, etc. For the ATM business, the interface types provided by the network include E1, E3, STM-L, etc.

(4) The user access method is flexible. The terminal device that supports frames or ATM protocols can be directly accessible; the local area network can be directly accessible through roads and risks and LAN switches; other protocol terminals can be accessed through FRAD devices. In addition, due to the built -in FRAD function of the network port itself, terminals support HDLC, SDLC and PPP protocols can also be directly accessible.

(5) Support the frame of the frame.
3. China ’s Internet

The introduction of China LNTERNET

The development history of China Internet is divided into three stages.

The first stage from L986_L994. This stage is mainly through the network line of the Chinese Academy of Sciences, and realizes Email in Europe and North America. The earliest use of the Internet in the Chinese science and technology community started from L986. Some domestic scientific research units have made online database retrieval through long -distance calls to some countries in Europe. Soon, the connection of these countries to the Internet is used to communicate with E.Mail. The units that realize this communication have successively included the Institute of North East Computer Application and the Institute of High Energy Physics of the Chinese Academy of Sciences. The units that have been reposted by E.Mail are mainly in Europe, such as the University of Karlsroe in Germany, GMD in Germany, CERN in Switzerland, Norway, France, etc.

L989, China ’s ChinaPac (X.25) public data network was basically opened. Although ChinaPac is not large, it has an international connection (X.75) with the public data network (X.25) in France, Germany, etc. (X.75).

L in 1990, the domestic research units such as Beijing Computer Applied Research Institute, the Institute of High Energy Physics of the Chinese Academy of Sciences, the North China Computing Institute, and the 54th Research Institute of Shijiazhuang Department of the Ministry of Electronics have successively used their computers to X .28 or X.25 connects to ChinaPac. At the same time, using computers in European countries as a gateway, we can transfer to the Ⅰ TNTERNET | and Division on the X.25 network, so that Chinese CHINAPAC technology users can communicate with Internet users with E-mail.

L in March of 1993, in order to support foreign scientists using Beijing positive and negative electronic collision to perform high -energy physical experiments in order to support foreign scientists, it opened a 64KBPS international data channel in order to support foreign scientists. The Chinese Academy of Sciences in the western suburbs of Beijing and the Stanford Linear Accelerator Center (SLAC) in the United States (SLAC), running the Decnet protocol, cannot provide a complete internet function, but the transfer of SLAC machines can communicate with Internet. Users use the international network to log in to the VAXLL/780 (BEPC2) of the Institute of High Energy Physics of the Chinese Academy of Sciences by using the LAN or dial -up line. With the 64Kbps special channel, the communication capacity is dozens of times higher than the international dial -up line and the X.25 channels, and the communication costs are reduced by ten times. Greatly promoted the application of Internet in China.

It stage from 1994-1995, this stage is the development stage of education and research network. Beijing Zhongguancun area and Tsinghua and Peking University formed NCFC networks. In April L994, the 64KBPS dedicated connection of the International Internet was opened. At the same time, there was also the highest domain name (CN) server in China. This is China that really joined the international MiTERNET ranks. Since then, China Education and Scientific Research Network (CERNET).

The computer network information center (CNIC, CAS) of the Chinese Academy of Sciences was completed in April of L994. Since the beginning of L990, the center has hosted a "China National Computing and Network Facilities" (NCFC), which is a project jointly invested by the World Bank loan and the State Family Planning Commission. The project content is to build a super computing center in Zhongguancun area for scientific calculations for scientific research users in this area. In order to facilitate the use of supercomputers, more than thirty institutes in Zhongguancun area of ​​the Chinese Academy of Sciences and two universities, Peking University and Tsinghua University, all use optical cables. Among them, the network part was completed in L993, and in March 1994, a 64Kbps international line was opened to the United States. The router was opened in April and officially connected to the Internet. NCFC later developed into China Technology Network (CSTNET).

Cernet is a national education and scientific research network approved by the National Family Planning Commission of China and the construction and management of the National Education Commission. The communication of information resources and connect with the existing international academic computer network.

The third stage is after 1995, and the commercial application stage began at this stage. In May, the Ministry of Posts and Telecommunications opened the Chinese public Internet network, namely Chinanet. In September of L. in September, the Tunzi Ministry CHINAGBN opened, and ISPs in various places were also opened. By the end of L996, there were more than 30 North Beijing.

At present, there are four networks (referred to as Internet networks) approved by the state (referred to as Internet networks) that can directly interconnect with Internet: CSTNET, Chinanet, CERNET. and Gbnet. Their completion time, the nature of the operation management unit and business such as:

The network name operation management unit international networking time business nature
CStnet Chinese Academy of Sciences 1994.4 Technology
chinaNet Post and Telecommunications Department 1995.5 Commercial
CERNET National Education Commission 1995.11 Education
gbnet Electronics Department 1996.9 Commercial

The development of computers on the Internet of China Internet Network is rapid. There is no complete data in China. From the Internet, the data developed over the years is as follows:

D number of hosts increased the number of domain names
94.0L 0
94.07 325
95.0L 569
95.07 1023 95
96 .01 2146 110% 153 61%
96.07 11282 426% 475 210%

The China Telecom's prediction of China's Internet users will reach 10 million in 2000. China Internet Information Center (CNNIC) is responsible for managing and running the top domain name CN in China.

INTERNET's history and development
internet originated from Arpnet, the predecessor of the predecessor of DARPA (DEFENSE Advanced Research Projects Agency), which was used in 1969. Since the 1960s, ARPA has provided funds to computer departments in American universities and some private limited companies to promote research on computer networks based on group exchange technology. In 1968, ARPA established the ARPANET network project. This project is based on such a dominant idea: the network must be able to withstand the test of the failure and maintain normal work. Once a war occurs, when a part of the network loses the ability to work due to attacks, a certain part of the network loses its ability to work, and the ability to work, and the ability to work due to attacks, and the ability of the network will lose its ability to work. Other parts of the network should be able to maintain normal communication. Initially, ArpaNet was mainly used for military research purposes. It has five major characteristics:
⑴ Support resource sharing;
⑵ uses distributed control technology;
n
⑷ communication control processing uses communication control processing Machine;
分 分 机 uses layered network communication protocols.
In 1972, ArpaNet met with the public for the first time at the first computer background communication international conference and verified the feasibility of group exchange technology. As a result, ArpaNet became a sign of the birth of modern computer networks.
arpnet's other major technical contribution is the development and use of the TCP/IP protocol cluster. In 1980, ARPA Investment added TCP/IP to the core of Unix (BSD4.1). After BSD4.2 version, the TCP/IP protocol became the standard communication module of the Unix operating system. In 1982, Internet was merged by several computer networks such as ArpAnet, Milnet. As an early backbone network of Internet, ArpANET test laid the foundation and development of the existence and development of the Internet. It solved a series of theories and theory and the interconnection of the heterogeneous machine network. technical problem.
In 1983, ArpaNet split into two parts: ArpAnet and Milnet for pure military. In January of that year, Arpa used the TCP/IP protocol as the standard protocol of Arpanet. After that, people called this Internet Internet with ArpaNet as the Internet. It is easy to use and excellent efficiency.
At the same time, the generation and vigorous development of the LAN and other wide -area network played an important role in the further development of the Internet. Among them, the most noticeable is the National Science Foundation NSFNET established by the National Science Foundation NSF (NATIONAL Science). In 1986, NSF established six supercomputers. In order to enable scientists and engineers across the country to share these In the supercomputer facilities, NSF establishes its own TCP/IP -based computer network NSFNET. NSF has established a computer -wide area network divided by the region across the country, and connects these regional networks with super computing centers. Finally, the super computing centers are connected. The composition of the regional network is generally geographically limited in a certain region. In terms of management, it is interconnected by a computer that belongs to a certain institution or a user that has a common interest. The high -speed data dedicated line constitutes the main network of NSFNET. In this way, when a user's computer is connected to a certain area, in addition to using the facilities of any super computing center, you can communicate with the Internet with an online user, and you can also get the network. A large amount of information and data provided. This success made NSFNet completely replaced ArpaNet in June 1990 and became the main network of Internet.
NSFNET's biggest contribution to InterNet is to open the Internet to the whole society, not just used by computer researchers, government staff and government contractors as before. However, with the rapid growth of online communication, NSF has to adopt updated network technology to meet the needs of development. In September 1990, Merit, IBM, and MCI jointly established a non -profit organization -advanced network and science company ANS (Advanced Network