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2025-01-15 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Network Security >
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How to solve the bottleneck of Internet development?
What is the new application trend of Internet?
First of all, the development of Internet is to get out of the predicament and expand its capacity, and then it is possible to continue to launch new applications and use them freely. Now we will start with the development of network lines and talk about the broadband access technology that has become a hot spot in communication in recent years, as well as the new application trend of Internet.
1. The development of access technology
Access technology, also known as "last kilometer" technology, represents a connection from the end user to the local telecommunications service provider. We are already familiar with the technologies such as PSTN dial-up, ISDN and private line, while the access technology has developed rapidly in recent years. The more mature ones are: ADSL,ADSL, also known as asymmetric digital subscriber line, is one of the most widely used DSL family technologies (HDSL, VDSL, IDSL, etc.). Its biggest advantage is that it uses the existing telephone twisted pair as the transmission medium, so the cost is low, but the access bandwidth is much faster than the PSTN transmitted by the telephone line (currently the highest 115.2Kbps). Theoretically, the downlink rate from the office to the user can reach 7-8m, the actual downlink rate is generally 1.5-2Mbps, and the uplink rate from the user to the office is hundreds of Kbps, which is much higher than that of PSTN. The asymmetry of ADSL is consistent with the network access characteristics of end users-most applications of individual users obtain data from the Internet in the way of customers, such as WWW and FTP, and only send a large amount of data to the network at individual times, such as sending e-mail with multimedia information, so the amount of downlink data is large and the amount of uplink data is small, which is also asymmetric.
2. Cable modem
Cable modem is a very suitable access technology for home users. On the basis of cable TV, it changes the backbone of the distribution network into optical cable, completes the photoelectric conversion at each service node, and then sends the transmission signal to the user's home by coaxial cable, which can effectively realize the services such as Internet access, TV on demand and data telephone, and has a broad market prospect. Cable transmission is also asymmetric. The downlink rate of each service node is as high as 10-30Mbps and the uplink rate is about 2m. But unlike ADSL, it is a shared network. The actual available bandwidth per user is inversely proportional to the number of Internet users connected to the node. Even so, the bandwidth that users can enjoy is considerable. The biggest obstacle to the development of cable modem application is the two-way transformation of cable lines-traditional cable TV is mostly one-way transmission, while data access is two-way, so it is necessary to implement line transformation to adapt to this new application. Before the transformation is completed, there is also a temporary solution: the downlink data is transmitted by television cable, and the uplink data is transmitted back by telephone line.
3. Wireless access technology
As a supplement to wired access, in areas where wired access is not convenient, wireless communication equipment is used to connect users to the local telephone exchange network, which is collectively referred to as wireless access system. Wireless local loop system technology comes from the following three aspects:
(1) from the cellular mobile communication system;
(2) it comes from large area communication system, digital cordless telephone system, digital microwave and satellite communication system. Zone system mainly refers to trunking communication system.
(3) it comes from a dedicated wireless local loop system with high power, large coverage and low cost. With its unique advantages, it was quickly accepted by the market and developed rapidly. At present, almost all the major communication companies in the world have typical products.
CDMA (Code Division multiple access) and its derived wireless local loop technology have incomparable advantages over other wireless access technologies and represent the development direction of wireless access technology. The development of access technology fully reflects the application trend of "three networks in one": ADSL uses the original voice carrier telephone line to transmit data, cable modem uses the original image carrier cable TV to transmit data, and the familiar IP phone transmits voice through all kinds of data carriers. Therefore, the future data network, television network and telephone network will no longer be isolated from each other, and will jointly contract the service of data, voice and image integration, thus alleviating the bandwidth pressure of Internet.
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