Internet access methods

In recent years, with the development of the communication industry, the number of Internet access methods has also increased. Here we mainly introduce the most widely used PSTN dialing methods, including the introduction of ADSL. When it comes to access networks, we must first involve a bandwidth problem. With the continuous development and improvement of Internet technology, the bandwidth of access networks is divided into narrowband and broadband. Industry experts generally think that broadband access is the future direction of development. The network structure of the GPON broadband carrier is shown in 1. The entire city network consists of the core layer, convergence layer, edge convergence layer, and access layer. The access part from the Community end to the end user is usually the last kilometer, as shown in location 1 in the entire network. Currently, GPON supports the following Internet access methods: PSTN, ISDN, DDN, LAN, ADSL, VDSL, Cable-Modem, PON, and LMDS9, they have their own advantages and disadvantages.

PSTN Dialing: the most widely used

GPONPSTNPublished Switched Telephone Network (public Telephone exchange Network) technology is the use of PSTN to achieve user access through MODEM dialing. This access method is an Internet access method that everyone is very familiar with. Currently, the maximum speed is 56 kbps, which has reached the channel capacity limit determined by Xiannong's theorem, this speed is far from enough to meet the transmission needs of broadband multimedia information. However, due to the popularity of telephone networks, user terminal equipment Modem is very cheap, which is about 100 ~ An account can be opened between RMB 500 and no application is required. If you have a computer at home, you can directly access the Internet by connecting the telephone line to the Modem. Therefore, PSTN dial-up access is relatively economical and is still the main means of network access. With the development and popularization of broadband, this access method will be eliminated.
ISDN dialing

GPONISDN (Integrated Service Digital Network) access technology, commonly known as "one-line communication", uses Digital transmission and Digital exchange technology, integrates telephone, fax, Data, images, and other services into a unified digital network for transmission and processing. Using an ISDN User line, users can call and send and receive faxes while surfing the Internet, just like two telephone lines. The basic ISDN Rate Interface has two 64kbps information channels and a 16 kbps signaling channel, 2B + D for short. When a call is made, it automatically releases a B channel for telephone answering.

GPON is similar to a Modem used for dial-up Internet access. You also need dedicated terminal devices to use ISDN, which are mainly composed of network terminal NT1 and ISDN adapter. The network terminal NT1 is as essential as a user access box on a cable TV. It provides interfaces and Internet access methods for the ISDN adapter. The ISDN adapter and Modem are also divided into two types: Internal and External. the built-in ones are generally called ISDN built-in cards or ISDN adapter cards. The external ISDN adapter is called TA. The price of the ISDN built-in card is 300 ~ It is about 400 yuan, while TA is about 1000 yuan.

The user needs to apply for an account to access through ISDN dial-up. The initial installation fee varies depending on the region, and the cost generally ranges from several hundred to 1000 yuan. The maximum bandwidth of ISDN is 128 kbps. Various test data shows that the speed of Dual-line access cannot be doubled. From the development trend, narrowband ISDN cannot meet the needs of high-quality broadband applications such as VOD.
Ddnleased line: for Group Enterprises

GPONDDN is short for Digital Data Network. It is a new type of Network that rapidly develops with the development of Data communication services. DDN's backbone network transmission media include optical fiber, digital microwave, satellite channels, and so on. Common cables and twisted pair wires are used on the user end. DDN combines digital communication technology, computer technology, optical fiber communication technology, and digital cross-connection technology to provide a high-speed and high-quality communication environment, A leased line lease circuit for point-to-point and point-to-point transparent data transmission is provided to transmit data, images, sounds, and other information to users. DDN communication rate can be at N × 64 Kbps (N = 1 ~ 32), of course, the faster the speed, the higher the rental fee.

The GPON user needs to apply for an account to rent a DDN business. DDN charges can generally be based on monthly subscription and traffic calculation, which is different from the pay-as-you-go billing method for dial-up Internet access. The rental fee of DDN is expensive, and ordinary individual users cannot afford it. DDN is mainly for enterprises that need comprehensive use such as group companies. DDN charges vary according to different bandwidth rates. For example, if China Telecom applies for a 1000 kbps ddnleased line in the region, the monthly rental fee is about yuan. Therefore, it is not suitable for access by community residents and is only attractive to community commercial users.

ADSL: Personal Broadband popularity

GPONADSL (asyuncrical Digital Subscriber Line, asymmetric Digital user loop) is a technology that provides broadband data services through common telephone lines. It is also a promising Internet access method. ADSL is well known as "network express" and is favored by many users due to its high downlink rate, high bandwidth, excellent performance, convenient installation, and no need to pay telephone bills, it has become another new and efficient Internet access method after Modem and ISDN.

The biggest feature of the ADSL solution is that there is no need to transform the signal transmission line. You can use a common copper telephone line as the transmission medium and use a dedicated Modem to achieve high-speed data transmission. ADSL supports the uplink speed of kbps ~ 1 Mbps, downlink speed 1 Mbps ~ 8 Mbps, with a valid transmission distance of 3 ~ Within 5 kilometers. In the ADSL access scheme, each user has a separate line connected to the ADSL local terminal. Its structure can be viewed as a star structure, and the data transmission bandwidth is exclusive to each user.

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