| With the rapid development of Access Network and diverse needs of user, the Access Network is tending to be a multi-protocal platform on the scale and structure. At the same time,The competition in communications market is becoming gragually fiercer.How to make use of the network resources and improve the network performace to fit in with the multi-variable enviroment, is becoming a way of communication enterprise to continously and effectively improve competitive power.In the long term, it is no doubt that the developing trend of access will be FTTH (Fiber to The Home). But, due to the high-cost of FTTH and no universal requirements of ultra wideband, at present, the practical approach is to use a set of access platform to lealize the fusion of multi-business and multi-technology.That is to say to use a mothed to lealize smooth transition to FTTH."Fiber replace copper"plan means to extend fiber and shorten copper line as much as possible to move the physical location of DSLM to user side, therefore, to increase the transmission bandwidth of NT.In this artical, we describe the Access Network design technology development after the occur of AN.Combined with practical requirements of telecommunication carrier, dicuss and analyze the Access Network design problems we meet from the perspective of triple play .We can find how the Litespan1540 Access Network system to lealize multi-business access and the advancement opening bus design strategy of the Litespan1540.In the first chapter, we analyze the application and technology of Access Network in the telecommunication market, also we find some problems in this market, new technology pushes the Access Network market forwad, and it's the most object of this article. The main content of the second chapter is the basic concepts of Access Network, including typical technique, classification feature, ADSL modem and architecture of ADSL Access Network system.In the third chapter, based on the opening feature of the Litespan 1540, we introduce the design technique of MLS, architecture and performance of the bus in detail. We design the line cards according to function units and then integrate the line cards using MLS slots to make up a complete Access Network system, this strategy well adapted to IP access.In the forth chapter, we design a new type broad band card GEBC, which is used in IP access system, lealize the standard interface of Ethenet by using the Motorola powerpc MPC8260 high performance chip.The GEBC has two parts, they are LANx switch and NT net control. In the two parts we analyze the core technology about Ethenet interface.In the fifth chapter, we introduce the design technology of the line card EFLCA/B used in the MLS. EFLCA/B is a broad band line card based on Ethenet. We design the function unites that compand the EFLCA/B separately. The main units include power module, clock generate and distribute module, IXP2350 network processor and interrupt module. In the interrupt module design, we use the CPLD technology to simplify the whole design greatly. At the end of the chapter, we describe the development platform of test program and principle of the main function test segments used by the line card EFLCA/B.In the sixth chapter, it's the conclusion and foreseeing. |
PDF Full Text Request