SDH Background

Birth SDH technology has its inevitability, with the development of communications, information transfer requires not only a voice, as well as text, data, images and video. Coupled with the development of digital communications and computer technology in the 1970s and 1980s, has been found in the T1 (DS1) / E1 carrier systems (1.544 / 2.048Mbps), X.25 frame relay, ISDN (Integrated Services Digital Network) and FDDI ( Fiber Distributed Data Interface) and other network technologies. With the advent of the information society, people want modern information transmission network quickly and cost-effectively provide a variety of circuits and services, and the complexity of the bandwidth limitations of the above-mentioned network technology because of its monotony of business, expanded only in the original modify or improve within a frame has been of no avail. SDH is in this context to develop. In a variety of broadband fiber access network technologies, using SDH technology access network system is the most common. SDH solve the birth home due to bandwidth limitations behind the development of the medium and the backbone network and customers' business needs, and user generated between the access and core network "bottleneck" problem, while improving the lot of bandwidth transmission line utilization. SDH technology since the introduction of the 1990s, it has been a mature, standard technology, the backbone network is widely used, and the price is getting lower and lower, application SDH technology in the access network can be enormous bandwidth in the core network and technology advantages into access networks and take advantage of SDH synchronous multiplexing, standardized optical interface, a powerful network management capabilities, flexible network topology capability and high reliability benefits, benefit from long-term construction and development of the access network .