Newbie road 5: select a broadband Internet connection line

[It168] Choosing a suitable broadband line makes your own Broadband Router even more powerful. Currently, common wide-line channels include XDSL, CM, fttx + LAN, PLC, DDN, satellite access, and microwave communication. Which of the following broadband access methods is better?

XDSL

XDSL refers to the digital user line access technology developed on telephone lines. Currently, it is commonly used in two types: ADSL and VDSL.
① ADSL (Asymmetric Digital user line)
ADSL allows asymmetric high-speed data transmission on a pair of twisted-pair copper lines without affecting existing telephone services. The upstream speed of ADSL is 224kbps ~ 640 Kbps, downstream transmission rate 1.544mbps ~ 9.2 mbps; the transmission distance is 2.7 ~ 5.5 km. Practice has proved that the asymmetric transmission ADSL technology is most suitable for applications such as high-speed Internet access and video on demand, and has great development potential.
② VDSL (very high bit rate digital user line)
VDSL is the development direction of ADSL and the most advanced digital user line technology. VDSL generally uses DMT modulation to implement digital transmission on a pair of Copper Twisted Pair wires. the downlink speed of VDSL can reach 13 ~ 52 Mbps, uplink speed up to 1.5 ~ 7 Mbps, the transmission distance is about 300 meters ~ 1.3 km.

Fttx + LAN

Fttb + LAN (LAN) broadband access network in fttx is the most reasonable, practical, and cost-effective broadband access method.CommunityAnd 10 MB to the building and 10 MB to the user. It provides high-speed access for residential users. It does not provide common voice services, so fttb + LAN can only access the Internet and cannot make phone calls.

Cm

A cable modem is also known as a cable modem. Its English name is Cable Modem (cm for short). It mainly uses a cable TV network for data transmission. In principle, cable modem and traditional modem transmit data within a frequency range of the 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 TV companies generally change from 42mhz ~ A 6 MHz channel is separated from a television channel between MHz for downstream data transmission. Generally, the downstream data is modulated by 64QAM (orthogonal Amplitude Modulation). The maximum rate is 27 Mbps. If 256qam is used, the maximum rate is 36 Mbps. Generally, the upstream data passes through 5 ~ In order to effectively suppress the accumulation of upstream noise, a period of spectrum between MHz is usually transmitted. For better noise environments than 64QAM. The maximum uplink speed is 10 Mbps.

PLC

PLC (Power Line Communication) is Power Line Communication. By using the transmission current wire as the communication carrier, the PLC has great convenience. As long as there is a power outlet in the room, no dial-up is required, you can immediately enjoy 4.5 ~ High-speed network access at Mbps to browse webpages, make phone calls, and watch online movies. In addition, the telephone, television, audio, refrigerator and other household appliances in the house can be connected by PLC for centralized control to realize the dream of "smart home.

DDN

What is DDN? It is a data transmission network that uses digital channels to transmit data signals. It is mainly used to provide users with a digital data transmission channel with permanent and semi-permanent connections, which can be used for communication between computers or for transmitting digital fax, digital voice, digital image signal or other digital signal. A permanent digital data transmission channel is an exclusive bandwidth circuit that establishes a fixed connection between users and keeps the transmission rate unchanged. The digital data transmission channel with semi-permanent connection is non-interchangeable for users. However, the user can apply and the network administrator can modify the transmission rate, data transmission destination, and transmission route. Network operators provide users with flexible and convenient digital circuit leasing services for various industries to form their own private networks.

DDN not only applies to meteorology, public security, railways, hospitals, and other industries, but also involves real-time data exchange for securities, banking, and gold card projects. DDN bandwidth generally provides data bandwidth of 9.6kbps-2 Mbps.

Satellite access

The advantage of large bandwidth and wide coverage of satellite channels is used to transfer downstream channels from common dial-up lines to satellite channels to achieve high transmission speeds.