Application of Internet Access Mode

First, the traditional dial-up Internet access.

Internet dial-up access

Traditional dial-up Internet access uses traditional analog modem and traditional analog line POTS (Ordinary Old Telephone Service). Both the user's computer and the remote access server RAS of the Internet access service provider ISP are connected to the telephone network through modems. Theoretically, its modem can reach the speed of 56k bit/s, but in fact, due to the influence of telephone line quality and distance, the speed of general telephone dial-up Internet access can only reach about 30K, or even lower. Telephone lines are built to transmit audio signals, and digital signals output by computers cannot be directly transmitted on ordinary telephone lines. At one end of communication, it is responsible for converting the signals output by the computer into analog signals that can be transmitted through ordinary telephone lines, and at the other end, it is responsible for converting the signals received on telephone lines into digital signals that can be processed by the computer.

Installation and cost: After applying for opening an account with ISP, you can get an account to dial up the Internet, or you can use public accounts such as 16300 to dial up. Generally speaking, these fees include three parts: first, the account opening fee, the procedure and production fee for applying for an account with ISP; Internet usage fee: e-mail space exceeds free disk space, and connection time is charged; Third, telephone charges: the charging rules for answering the phone. (At present, some ISPs, such as 163, reduce the telephone charges for surfing the Internet to about half of the ordinary telephone charges). Some ISPs also offer a monthly discount service. I don't remember the time, but only pay a fixed monthly rent, which is about 100. Of course, you can also use public accounts and network cards provided by some ISPs to dial up the Internet directly, and you don't need to apply to the ISP, and you can charge by time according to specific standards.

Suitable for families: families with less internet time and frequency and low requirements for network speed.

Second, "one line" online.

Introduction to ISDN

Integrated Services Digital Network (ISDN) is usually called "one-wire communication". The core technology of ISDN is to adopt asynchronous transmission mode ATM to realize efficient transmission, switching and multiplexing. "First-line communication" combines two B channels and one D channel into a digital channel of 144kbps (64kbps for B channel and 16kbps for D channel), and the user computer accesses the Internet through a complete digital channel ISDN adapter with the rate of 144kbps. SDN is different from the traditional dialing, and its transmission process is all digital signals, which do not need modem for modulation and demodulation. The user computer of ISDN is connected with the ISDN switch of ISP through TA and NT, and the digital line is used as the communication line. Users access ISDN switches by dialing.

Installation and cost: After completing the ISDN application procedures in telecommunications departments, the installer will come to your door soon, install the line, NT, TA and special dialing software for you, and give you an ISDN user number. You can install a new line or modify the existing telephone line, which will require you to pay the rent for the additional line. If you modify the original line, your original telephone service will be stopped unless you buy a digital telephone. The network terminal NT is given by telecom for free, but the TA and ISDN adapter cards need to be purchased by themselves. Therefore, the general family ISDN installation fee is above 1500 yuan, and there is a monthly rent. The rent for home ISDN is about 100 yuan.

Suitable for family: users who spend more time and frequency surfing the internet and want to browse the web more smoothly and faster. With the rise of ADSL, ISDN gradually withdrew from the market.

Thirdly, asymmetric digital subscriber line.

Brief introduction of ADSL

Asymmetric digital subscriber line (ADSL). ADSL is the most striking technology at present, which is different from the common analog subscriber line POTS (ordinary old telephone service). It is a transmission technology that provides high-speed digital access by using a load phone on a trunkless subscriber line, and it belongs to a new broadband transmission technology that uses xDSL (Digital Subscriber Line) for high-speed digital loop access. The upload speed of ADSL Modem can be from 64K bit/s to 640K bit/s, and the downlink speed can be from 1.5M /s to 9M/s, which has fully met the requirements of ordinary families for video and voice data transmission. Because of the difference between the upper and lower transmission speeds, it becomes an asymmetric transmission technology. As long as ADSL service is provided in the local telephone office (telecommunication bureau or ISP), ADSL Modem are installed in the vast number of clients, and the existing copper telephone lines are used as communication lines for dial-up access, users can enjoy the original telephone service and quickly obtain various services on the Internet.

Installation and cost: ADSL installation is generally free, and ISPs all over the country will provide on-site service to install ADSL modems and dial-up software for you. However, ADSL modems need to be purchased, and the general household ones are around 500 yuan. The monthly fee of ADSL is not expensive either, but the telecom departments vary from place to place. General household 100 yuan, business use is more expensive. If you surf the Internet frequently and have high requirements on network speed, it is recommended to install ADSL. However, there are still some cities in China that have not opened ADSL services, and it will take some time to install them.

Suitable for families: families who often surf the Internet, have high requirements on network speed and need voice and video data transmission.

Fourth, "wired" access

Brief introduction of "wired communication"

"Wired connection" refers to the broadband network on the cable TV network. Cable connection is based on HFC (Hybrid Fiber Coaxial Cable Network). Compared with the original cable TV network, it uses optical fiber technology for data transmission on the trunk line, while the original analog coaxial cable mode is still used for wiring and lead-in lines. To surf the Internet through cable TV, users only need to install a cable modem at home, one end is connected to cable TV, and the other end is connected to a computer through a network cable, so they can surf the Internet. The maximum downlink speed of WireConnect is 1 10Mbps, and the uplink speed is 80Mbps. Compared with10mbps LAN uplink and downlink, 2M ADSL downlink and 5 12K uplink, WireConnect has great advantages. By enabling the excellent traffic balancing strategy, the downlink speed of home users generally reaches 15Mbps, and the uplink speed reaches 10Mbps. It only takes a few seconds to download more than ten megabytes of files, and you can open multiple windows at the same time to watch multiple 800Kbps streaming video programs.

Installation and cost: Cable TV is generally managed by the cable TV company under the local radio and television department, and the installation is generally free. You can register in the user management department of the cable TV company, and the installer will automatically come to help you install the cable modem and dial-up software. Cable modems need to be purchased, but cable TV companies in many areas often give them away for free in order to expand their business, and the monthly subscription fee of cable TV is not expensive, but it varies from place to place.

Suitable for family: If you are a family who often surf the Internet and have high requirements on network speed, it is strongly recommended to install WireConnect, which is said to be the cheapest, fastest and most suitable broadband access method for family users. However, it should be noted that the WireConnect project depends on the two-way transformation of the cable TV network, and only some users in the living quarters who have undergone the transformation of the cable TV network can install it.

5. Other access methods.

There are many other access methods, such as other XDSL, optical cable access, data private line access to the mobile wireless access technology of the telecommunications sector and so on. But these are generally used for business purposes, and there are relatively few home visits. The following is just a brief introduction.

1. high-speed digital loop access technology line XDSL (digital subscriber line)

XDSL makes use of twisted-pair copper wire in the existing telephone network, and excavates the high-frequency bandwidth resources of twisted-pair copper wire through band coding technologies such as 2B 1Q, CAP (Carrier-Free Amplitude Modulation) and DMT (Discrete Multi-Tone), and realizes broadband access through bandwidth multiplication technology. At present, there are mainly the following types of xDSL: high bit rate digital subscriber line (HDSL), rate adaptive digital subscriber line (RADSL), multi-rate digital subscriber line (MDSL) and so on.

2. Optical Cable Access Network (OAN)

Optical fiber access network refers to the network form that uses optical fiber as the main transmission medium to realize information transmission in the access network. It has the advantages of large communication capacity, stable performance, anti-electromagnetic interference and strong security, and the speed can reach several gigabits per second, which is the focus of future network development. The user establishes a connection with the exchange office through an optical cable. However, both users and exchange offices receive electrical signals, so they need to perform electrical/optical (E/O) conversion at the exchange office and optical/electrical (O/E) conversion at the optical network unit (ONU). In order to achieve the connection. Optical fiber access According to the distance between the network unit (ONU) and the optical line terminal OLT, optical fiber access can be divided into various optical fiber access modes: FTTC (fiber to the roadside), FTTZ (fiber to the building), FTTO (fiber to the office), FTTH (fiber to the home) and so on. Its technical principle is basically similar, which is related to FTTH (fiber laying to the home).

3. Dedicated data line access in the telecommunications sector

There are X25, FR, DDN, ATM and other common data networks, which are undoubtedly a little overqualified for families. Moreover, the cost of the private line is very high, which is difficult for ordinary users to bear. Generally, it is installed by group users and enterprises and institutions, unless there are families with special requirements.

4. LAN access

Some families access the Internet through their local area network at work or school. Local area network can be divided into two categories from the perspective of media access control methods; * * * Sharing LAN and switching LAN. There are three main types of traditional LAN: Ethernet, token bus and token ring. At present, the most widely used should be Ethernet.

5. Mobile wireless access technology

Mobile wireless access is to provide data mobile access service by using the most popular mobile communication system. The most widely used scheme is the combination of GPRS and WAP, which can provide users with access rates from 9Kbps to 17 1.2kbps.