Internet Access Technology Study Notes

From the current development trend of the communication industry, the development of broadband networks will be a major direction, and also drive the constant updates of Internet access technologies. dial-up access and ADSL are our very common access technologies, here we will give you a detailed introduction. With the rapid development of the Internet, the demand for online resources is getting higher and higher, and the development of broadband networks is an inevitable trend. Although the current use of optical fiber technology can make the computer network's backbone network bandwidth enough, can completely solve the network "bottleneck" problem. However, the number of accesses from the user's home to the ISP network is enormous, and the investment in Broadband User Access networks will be even greater, resulting in the so-called "last mile" problem. To solve this problem, it is still under active exploration through technical transformation of existing network telephone networks, cable television networks, and computer networks, or completely adopting new technologies. In the long term, fiber-to-the-home is certainly the best option, but it cannot be achieved overnight. Sometimes, the user's needs are diverse. How to select an appropriate network access method based on the actual situation, in order to achieve fast, practical, convenient, and economical purposes.

GPON telephone network is the world's most widely used network, achieving narrowband Internet access technology is the most economical and convenient, but its data transmission rate is only 64 KB/s. Direct broadband data transmission based on telephone networks is not feasible. Considering that the bandwidth from the telephone switch to the user's line is wide, xDSL is a widely used Internet access technology. The real-time and bandwidth of cable TV networks are both good, and the coverage of urban and rural areas is large. The prospect of using existing TV networks alone is very good. The problem is that the technical transformation of existing TV cables should be carried out, changing one-way transmission to two-way communication, and broadband networks with exchange and network management functions still require huge investment.

To make wireless access easier for mobile users, GPON is now rapidly emerging. In the future, wireless communication networks will be connected by wireless access points through broadband networks to form a large, infinitely scalable wireless communication network. In short, there are a variety of Internet access technologies. Various users should select an appropriate access method based on their actual conditions and specific requirements.

1. dial-up access

GPON connects to the Internet through a telephone network through a modem, which is the primary method for early and current Internet Access Technologies for home users. This method is simple, cost-effective, and cannot achieve broadband access. The main function of GPON modem is to enable computer data to be transmitted over analog telephone channels. A modem can be divided into two functional parts: a modem and a modem. A modulation is used to send signals. It uses data signals to prepare a simulated signal called a carrier, so that digital signals can be transmitted over a telephone line. The modem receives a signal. It decrypts the received analog signal, restores it to the original digital signal, and sends it to the receiver. The modem does not change the data content. It only changes the data representation for transmission.

2 xDSL access

GPONDSL is the abbreviation of Digital Subscriber Line. X indicates the DSL family. Different x prefixes are used to represent different broadband solutions implemented online for digital users. Among them, adslasypolicric Digital Subscriber Line) is a non-symmetric Digital user line, HDSLHigh speed DSL) is a high-speed Digital user Line, SDSLSingle-line DSL) is a one-to-one Digital user Line, VDSLVery high speed DSL) A high-speed digital user line, while a DSL uses an ISDN User line. See table 1.
Currently, GPON has replaced ISDN and become a choice for commercial and domestic users who access the Internet at a higher speed. XDSL uses digital technology to transform existing analog telephone user lines so that they can carry broadband services.

Considering that the broadband service that users need when using WWW is mainly because there is a large amount of information downloaded from Internet sites, and the amount of information uploaded to Internet access technology sites is small, make the upstream and downstream bandwidths of ADSL Asymmetrical. In this way, the economy can meet the requirements. The minimum frequency is 0 ~ 4 KHz, used to transmit traditional phone signals. 20 ~ The 50 kHz frequency band is used to transmit upstream digital information. From 150 ~ The 1.5 kHz frequency band is used to transmit data at a rate of 140 Mb/s downstream digital information ~ The 6.3 KHz frequency band is used to transmit data at a rate of Mb/s downstream digital information.

GPONADSL is suitable for residential areas with low user density and small enterprises or departments geographically dispersed. Because these users are often unable to lay optical fiber. Another reason is that the twisted pair wires still occupy more than 90% of all user lines, and the telephone lines in the telephone network can be used. This is also the reason why telecom companies are vigorously promoting the use of ADSL. It is easier to install ADSL,

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