Various Internet access speeds

There are multiple access methods for accessing the Internet at ordinary times, and the access speed provided by the ISP service provider is different from the download speed, which is hard to understand. The following lists the Internet access speeds for accessing the Internet:
1. PSTN (published Switched Telephone Network, public telephone exchange network) technology uses PSTN to implement user access through MODEM dialing. A modem card is installed on the computer and connected to the Internet through dialing through the telephone line. The speed is only 56 kbps.
2. ISDN (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.
3. 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 access technology. 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 access method after modem and ISDN. 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.
4. VDSL is faster than ADSL. With VDSL, the maximum downloading rate within a short distance can reach 55 Mbps, And the upload speed can reach 2.3 Mbps (19.2 Mbps or higher in the future ). VDSL uses a pair of copper wires, with a valid transmission distance of more than 1000 meters. However, the VDSL technology is still in its infancy, long-distance applications still need to be tested, and the popularization of endpoint devices also takes time.
5. Cable-modem is an ultra-high-speed modem that has been used for trial in the last two years. It uses a ready-made cable TV (CATV) network for data transmission, it is already a mature technology. With the development of cable TV networks and the continuous improvement of people's quality of life, using Cable Modem to access the Internet through cable TV networks has become a high-speed access method that attracts more and more industry attention. Because cable TV networks use analog transmission protocols, a modem is needed to convert digital data. In principle, cable-modem and traditional modem transmit data within a frequency range of cable (Cable) after modulation. The transmission mechanism is the same as that of common Modem, the difference is that it performs modulation and demodulation through a certain transmission frequency band of CATV. Cable modem connections can be divided into two types: symmetric rate type and asymmetric rate type. The data upload (data upload) Speed of the former is the same as that of data download, both in kbps ~ 2 Mbps; the latter's data upload speed is kbps ~ Data download speed: 2 Mbps to 10 Mbps ~ 40 Mbps.
6. The PON (Passive Optical Network) technology is a point-to-multiple-point Optical Fiber Transmission and access technology. the downlink adopts the broadcast mode and the uplink adopts the time division multiple access mode, A tree, Star, bus, and other topology structures can be flexibly formed. You only need to install a simple optical splitter when you do not need a node device at the optical pivot, it has the advantages of saving optical fiber resources, sharing bandwidth resources, saving investment in data centers, high equipment security, fast network construction, and low overall network construction costs. Pon includes ATM-PON (APON) and Ethernet-pon (EPON. APON technology has developed early, it also has the unique characteristics of integrated service access, QoS service quality assurance, ITU-T g.983 suggests to standardize the ATM-PON network structure, basic composition and physical layer interface, the Ministry of Information Industry of China has also formulated sound APON technical standards. Pon access devices are mainly composed of OLT, ont, and ONU. The OLT optical signals are divided into the ONU of the tree network by the passive optical splitter. One OLT can be connected to 32 ont or ONU, one ont can connect to 8 users, and The ONU can connect to 32 users. Therefore, an OLT can load up to 1024 users. The PON technology uses a single-core optical fiber for transmission. The maximum distance from the local terminal to the user side is 20 kilometers. The total transmission capacity of the Access System is 155 Mbps for both the uplink and downlink, the bandwidth used by each user can be flexibly divided from 64 Kbps to 155mbps. The user connected to an OLT shares the bandwidth of 155mbps. For example, the Fujitsu EPON product OLT device has a550, The ont device has a501, And the a550 device has up to 12 Pon ports, and each Pon downstream route to each a501 is mbps; the a501 uplink bandwidth connected to each Pon port is shared. The PON access technology is shown in figure 7.
7. LMDS access (Wireless Communication), which can be used currently Community A wireless access technology for broadband access. In this access mode, a base station can cover a region of 20 kilometers in diameter. Each base station can load 24 thousand users, and the bandwidth of each end user can reach 25 Mbps. However, the total bandwidth is 600 Mbps, and users under each base station share the bandwidth. Therefore, if a base station has a large number of users, the bandwidth allocated to each user is very small. Therefore, this technology is not suitable for the access of Community users, but its client devices can be bundled together and used for the interconnection of man networks of broadband operators. The specific practice is to create a base station in the data center of the aggregation point, and the Community data center around the aggregation data center can be used as the user end of the base station. If the Community data center is bound with four users, the bandwidth of the aggregation and Community data centers can reach 100 Mbps.
8. LAN access uses Ethernet technology and optical fiber cables and twisted pair wires to provide integrated wiring for the community. The specific implementation scheme is: laying optical cables from the Community machine room to the residential unit building, and laying cables in the building using five twisted pair wires to the user's home. The total length of twisted pair wires is generally no more than 100 meters, the user's home computer can access the Internet through the five modules on the wall through the five jumpers. The egress of the Community data center is connected to the man through optical cables or other media. LAN access can take full advantage of the resources of the residential area network to provide residents with a shared bandwidth of more than 10 MB, which is more than 180 times faster than dial-up, and can be upgraded to m or above according to the user's needs.
9. PLC, Power Line Communication Technology, refers to the use of power lines to transmit data and voice signals. The technology is to load the high frequency of information contained in the current, and then transmit it using a wire. the modem that receives the information then separates the high frequency from the current and transmits it to a computer or phone, to transfer information. On the basis of no re-wiring, this technology can carry data, voice, video, and other services on existing wires, that is, to achieve the integration of four networks. End users can connect to the Internet by plugging in the power plug. PLC uses the range of m to 30 m to transmit signals. During transmission, the user data is modulated using GMSK or OFDM modulation technology, and then transmitted on the power line. at the receiving end, the modulated signal is filtered out by the filter and then demodulated, the original communication signal can be obtained. The current communication rate varies between MB and MB depending on the specific device ~ Between 45 MB. The PLC device is divided into local terminal and modem. Local terminal is responsible for communication with internal PLC modem and external network connection. During communication, data from the user enters the modem modulation and is transmitted to the local device through the user's distribution line. The local device decrypts the signal and then forwards it to the external internet.
10. DDN is short for English 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.
11. GPRS/CDMA is the use of wireless network access by mobile phones.
Note: 1 k = 1024b
1B = 8B (one byte equals eight digits)
Generally, the Internet access speed refers to the number of BPS while the number of BPS for downloading files. BPS is short for bits per second. The transmission rate of network communication is measured in bps. BPS is short for byte per second. The download speed is usually measured in bps. For example, if the downstream bandwidth of the deployed ADSL instance is 2 Mbps, the download speed should be 256 kbps.
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