构建宽带IP城域网技术综述（国外英文资料）.docVIP

构建宽带IP城域网技术综述（国外英文资料） Construction of broadband IP city wan technology review 1 technical background With (DWDM) and optical transmission technology of broadband IP technology mature gradually, so a routing switches, and DWDM system has entered the commercialization, which makes the transmission backbone communications network speed greatly improved, has reached the level -tbps. Meanwhile, various broadband access technologies (XDSLS, Cable modems, HFC, etc.) have also developed relatively rapidly, and the access bandwidth requirements for personal users of 10mb / 100M have been lost. This way, traditional telecommunication networks such as SDH, PSTN, etc., build the urban data communication network and the way to access the Internet to become the new network development bottleneck. Traditional SDH, TDM man cannot meet the demand for high-speed, low-cost network services, its inherent limitations mainly displays in: 1) the further expansion of bandwidth capacity constrained. 2) rigorous timing requirements lead to complexity and high cost of equipment. 3) it was originally designed for voice business, which is not suitable for the sudden and asymmetrical operation of the data business, resulting in reduced efficiency. 4) it is mainly a ring network, and the knot points are not suitable for network structure. 5) provide business preparation time (more than a few weeks) and do not adapt to the changing requirements of the data business. 6) the recovery of spare ring road wastes resources. So changes to the metropolitan area have become inevitable. Currently, there are two main types of metropolitan area networks, one for the metro-dwdm scheme and one for MSPP. 2 Metro DWDM - 2.2.dwdm is the status of the metropolitan area network DWDM (WDM) technology is in optical time division multiplexing technology in the domain of synchronous transmission is carried out in a single optical fiber different wavelength of light waves, get data transmission speed and capacity. It mak