Broadband access and Bidirectional Transformation Technology

Comparison of HFC, XDSL, wireless access ( LMDS ), Ethernet, optical fiber access mode of broadband access way which is more suitable?

Several broadband access way has its characteristic:

HFC ( hybrid fiber coax )

The advantages of HFC network not only to provide the original cable television business, but also to provide voice, data and interactive services. Because the cable network home has been very popular, local area and even over telephone penetration rate, so HFC is recognized to the information highway.

Compared with the traditional wired network, HFC network main innovation to establish service area ( SA ) concept. The entire network with optical node is divided into a service area. Modification of HFC with bidirectional transmission of digital media information, open the VODNVOD (VOD ), distance education, telemedicine, Internet/Intranet fast access and voice telephone new value-added service. Radio and television departments force to promote HFC technology.

Disadvantages of HFC cable TV network structure of a portion of the optical fiber data collection star network, cable section collects dendritic distribution network. This kind of network structure in broadband speed integrated services network is unreasonable, the main cause of CATV network integrated services network reliability for different, integrated information network for network reliability.

Cable distribution network transmission channel, active filter passive filter, cable joint, severe descending transmission system reliability.

Broadband speed integrated information network for data communication, bit error rate, and cable with shielding, so that no electromagnetic leakage cable connector. But cable TV network equipment as the demand.

Network management issues. Cable television network, are generally not make network automatic management. The network function is, on this account to reflect, two on network maintenance management regularly patrol monitoring. Broadband integrated information network and modern intelligent communication network, and has very reliable, has an automated network management, network performance, configuration, fault, billing and other comprehensive management, to improve operation efficiency of network quality of service.

XDSL

Advantage through existing copper twisted pair are respectively with a modem, which realizes the transmission rate is increased several times. XDSL technology not only makes the copper twisted pair medium speed digital communication field occupy on the ground, but also plays a very important role. Lev xDSL technology in broadband access service advantage is very clear, first, to take full advantage of the existing copper cable telecommunications network resources, and the user at any time, without afresh each time the connection is established, while not affecting the telephone so that, each household exclusive speed channel, no blocking problem. The xDSL access, confidentiality, security by.

Inferior xDSL line can provide the speed distance copper quality is very sensitive, especially the increase in distance, crosstalk crosstalk increased, so that the line quality deterioration. The other, a considerable number of copper wire mesh China due to aging and other quality problems can not withstand a transmission rate.

Ethernet

Advantages of Ethernet technology is mature, cost, simple structure, stability, good extensibility, easy network upgrade, at the same time to realize the real-time monitoring, intelligent property management, district / building / home security, home automation ( such as remote control home appliances, visual doorbell, remote meter reading, etc.), to provide intelligent, information office, home furnishing, different levels to meet the information needs of people. User, network speed, fee.

Disadvantages we should pay attention to, using high-speed Ethernet access facing end equipment, lack of IP address resource quantity, the operation and management level of a problem.

LMDS

LMDS (local distribution business ) Local Multipoint Distribution Services shrinkage, microwave broadband service, belonging to the wireless fixed access means, the characteristics in wideband characteristics. LMDS data transmission rate of 1.2Kbps ～155Mbps support, and support for the agreement, including ATM, TCP, frame relay and IP. LMDS 's own characteristics, decision is more suitable for the city or the more densely populated areas; because the work frequency, communication quality is affected by rain, snow and weather effects.

Optical fiber

( optical fiber direct access ) nearly arisen kind of broadband access way. The utility model has the advantages of wide bandwidth, in order to reach the GHz level.

If the use of radio and television network advantage, so only by Cable Modem. While Cable Modem has a frequency division technology, time division technology code technology, how to choose? Code technology user bandwidth slightly less than the other two, but because of no on line modification, and cost more, so we think that the code technology will be the mainstream Cable Modem technology.

Optical transceiver and its new development

Face informatization construction make a spurt of progress, people for data, voice, image and other multimedia applications demand increases increasingly, Ethernet Broadband access way is therefore referred to a more and more important position. At the same time, optical fiber communication with its large information capacity, confidentiality good, light weight, small volume, no relay, long distance of transmission has been widely applied, fiber optic transceivers is the use of optical fiber the high-speed transmission medium well solves the problems in the transmission of ethernet.

Fiber optic transceivers is a short distance of the twisted pair telecommunications and long distance optical signal exchange Ethernet transmission media conversion unit, in many places, also known as the photoelectric converter. Enterprises in the information technology infrastructure, typically pay more attention to the router, switch and network card for node data exchange network equipment, but often neglect the medium converting the network core but essential equipment. Especially in some of the requirements for a high degree of information, the data flow of large government agencies and enterprises, network construction needs to directly connected to the optical fiber as the transmission medium of the backbone network, while the internal local area network transmission medium for copper wire, ensure that the data packets between different network smooth transmission medium conversion equipment necessary. Fiber optic transceiver includes three basic functional modules: OEMC, optical signal interface ( optical transceiver module ) and the signal interface ( RJ45 ), if equipped with network management functions include network management information processing unit.

With the development of fiber optic transceivers on the network capacity demand increase sharply, operator for the requirement of network management is increasing, the Ethernet transmission speed upgrade, an optical transceiver type and complexity are developing at an amazing speed. Because the optical fiber technology and the decline in the cost of capacity requirements increase, many telecommunications companies, local government, even for large enterprise groups have begun to optical fiber technology used in city area network ( MAN ) application. Therefore, once confined to remote and high-end backbone network optical fiber link technology is now available throughout the network facilities at each corner of the. However, the rapid increase of the number of optical fiber link application also caused a wide variety, sometimes even conflicting fiber optic transceivers will usher in rapid development according to authoritative market research agencies forecast, 2014 40Gbps/100Gbps Ethernet </a> transceiver market sales revenue will reach 545000000 yuan, of which 2/3 sales revenue from the 40Gbps module products. Because 40G/100G product standard in mid 2010, when the new product will enter the market, 40G/100G module development momentum will be shown increasingly. While the standard before the 40/100 transceiver product suppliers, such as Avago, Finisar, Opnext and Sumitomo, the market will play an important role in the development.