Research And Implementation Of The E1overIP Circuit Emulation Adapter

With the evolution of network technology and the convergence between different networks, the way of transmitting and switching with data packets as its basic unit will play the dominate role in the Next Generation Network (NGN). So the main research direction of the development of the next generation communication is to build a new network, which can provide integrated services for voice, data and video transmittion and achieve the transition and transformation from circuit switching to packet switching.TDMoIP, which can perform circuit simulation to achieve TDM business such as E1/T1and E3/DS3in the IP network, provides a viable technical support for this transformation. The basic principle of TDMoIP is to build a "tunnel" in the IP network, which can encapsulate the TDM business into packets periodically and transfer them to the receiving end through the IP network transparently. As a transitional mode, it connects IP network with existing TDM network to achieve seamless access, and completes the transition to a next generation information network while reserving the service quality of TDM business.In this thesis, the basic concepts and technical points of TDMoIP technology are introduced and the challenges of realization principally are analysed. As an application of TDMoIP technology, the design of EloverIP circuit emulation adapter system and implementation of the various functional modules in a research project are completed. The design mainly describes the key modules such as the clock recovery module and the queue management module. The clock recovery module can recover the accurate original clock with the use of digital PLL technology. The queue management module can realize the packet loss and the disorder process. Functional modules introduced above have been implemented by Verilog HDL. And adapter solution is timing simulated by the tool of Modelsim whose copyright is Mentor Graphics corporation. Finally, for a variety of board-level functional testing, it shows that the EloverIP circuit emulation adapters can achieve the desired objectives.