The Research And Implementation Of IP-DSLAM Line Termination Board Based On SHDSL

Because of the rapid development of economy and the fast spread of Internet in China, The demand in the market of broadband access network is growing sharply. Among all the technique of broadband access network, Digital Subscriber Line (DSL) which provides fast Internet access via the existing twisted-pair telephone wires,has become the leading actor because of its low cost and simple implementation. Single-pair High-bit-rate Digital Subscriber Line (SHDSL) is a new transport specification used in broadband access via digital subscriber line. The main purpose of this thesis is to research and implement a line termination board of the IP-DSLAM based on SHDSL.SHDSL can support the maximal symmetrical speed of 5.7Mbps both in upstream and downstream. It can resolve the disadvantages of asymmetrical transmission speed and short distance existed in present DSL so as to meet the requirement of symmetrical bandwidth for commerce. IP-DSLAM can realize the functions such as the aggregation of DSL users, the termination of ATM cells, the uplink of Ethernet ports and the access of IP backbone. Integrating the above two technologies as well as IMA, a new IP-DSLAM line termination board is designed.Firstly, the principles and network topologies of IP-DSLAM are learned and the protocol architectures to implement the scheme are analyzed. Secondly, the hardware circuit of IP-DSLAM line termination board is designed. The Inter-Working Function module is implemented in a totally new way, which realizes protocol exchange between ATM cells and Ethernet frames. Also SHDSL access module and IMA module are designed to realize the demands of high-speed communication and quality of service. Then, the board support package design is carried on under embedded real time operating system, which finishes system initialization, interface, interrupt handling and device access. Finally, some test schemes are proposed to test the function modules and holistic system.Test results are provided to verify system performance. The result proves that this system can totally satisfy the transmission of high symmetrical speed and far distance and plays a positive impetus for the further development of SHDSL technology and IP-DSLAM.