sip

Network communication China (Voipchina) at present the most popular IP deferent technology has 3 kinds, namely IP Over ATM, IP Over SDH or IP Over WDM. The different share of the different period that deferent technology of 3 kinds of IP will develop in telegraphic net and network produces his due effect, 3 person will coexist complementary. But will look from the perspective that faces future, IP Over WDM will be the technology that provides vitality most, its tremendous bandwidth potential and the IP business that explosive type grows are to comparative match, this kind of deferent to IP business optimal technology will make prospective network especially the dominant of backbone net is deferent technology.

In recent years, the swift and violent development of Internet, make IP technology obtain the high speed that never been able to have had toward communication and IT to develop. In last few years, no matter IP technology goes up from network structure, still be business is developed on transmission ability go up to obtain tremendous progress. 70 time put forward TCP/IP as agreement of the interconnection between the net, inside time of near 20 years, besides outside effect has in interconnection of American local area network, did not cause the attention of the outer world all the time. ITU-T is in very long this standard was not admitted inside period. The occurrence till the Web at the beginning of 90 time from go up at all changed this kind of position, IP net achieved express progress, corresponding IP technology also achieved express progress.

IP is network layer agreement, SDH, WDM is physical layer deferent technology, in two between need layer of link of a data, the signal that data link layer is in charge of offerring physical layer is changed into the signal that network layer place needs, at present the most popular IP deferent technology has 3 kinds, namely IP Over ATM, IP Over SDH or IP Over WDM.

Traditional enlarge look method is to use TDM(time answer is used) means, have time to telegraphic date namely disjunctive answer is used. No matter be the 34 Mbit/s-140 Mbit/s-565 Mbit/s of PDH, still be the 155 Mbit/s-622 Mbit/s-2 488 Mbit/s-9 952 Mbit/s of SDH, undertake according to this one principle. According to statistic, contain 2.5 Gbit/s) under 2.5 Gbit/s(when systematic speed, system every upgrade, the transmission cost of every bit drops 30% the left and right sides. Accordingly, upgrade in the system in the past in, what people thinks of above all and use is TDM technology. Use time answer to use (TDM) means is digital communication raises the transmission efficiency, significant step that reduces transmission cost. But rise quickly as what contemporary and telegraphic net asks to transmitting a capacity, use TDM means to already approached the limit of silicon and gallium arsenic technology increasingly, for example to present 10 Gbit/s, TDM already can be dug without too much latent capacity, and transmit the price of equipment very tall also, the influence of fiber-optic chroma chromatic dispersion and polarization model chromatic dispersion is increasingly aggravating also. People an increasing interest from report answer use to recover with move, use from smooth region namely all sorts of answer will improve transmission efficiency with means, rise answer with rate.

Since 1996, provide most representative is a cent answer with (WDM) system appeared. Alleged WDM technology is to make full use of the tremendous bandwidth resource that area of small loss of Chan Moguang fine brings, use a cent answer to use implement (close wave implement) , in send the smooth carrier wave that carries will different wavelengh to incorporate rise and send into fiber-optic undertake transmission. In sink, use by a cent answer again implement (cent wave implement) bear the weight of these different wavelengh the smooth carrier wave of different signal is apart answer with means. Because differ,the signal of smooth carrier wave of wavelengh can regard mutual independence (take no account of fiber-optic nonlinear when) , consequently two-way transmission problem is solved very easily, need to arrange the signal of two direction respectively only transmit in different wavelengh can. According to wave cent answer with implement different, can answer used wavelengh number is different also, differ to a few from 2, this depends on the removed size of wavelengh of allows smooth carrier wave.

[1] [2] issues one page