Based On The Tunnel Ip Broadcast Packet Exchange Mechanism And Its Applications In The Ems System

Energy Management System (EMS) is a modern integrated system for power dispatch automation based on computer technology. It provides the system engineers and operators with a powerful tool to improve system's reliability, which greatly facilitates the monitoring and controlling of the power grid by collecting and analyzing real-time data. Traditionally, EMS keeps the whole system's state information, such as system management information, communication management information etc., through broadcasting packets, which could not work properly in new generation EMS. New requirements and applications make EMS expand to large-scale and no longer be constraint in a single LAN, but broadcasting packets can not be transmitted among LANs.To solve the above problem, in this thesis, I first studied and compared three common communication modes, e.g. IP unicast, multicast and broadcast, then I proposed a new communication mode called tunneling-based broadcast by making a tradeoff between performance, cost and complexity in implementation. It possesses advantages of both unicast and broadcst, while it is easier to be implemented than multicast. Furthermore, I designed a TCP Broadcast Tunneling Protocol to apply to the practice system, which could transmit broadcasting packets through TCP unicast among LANs.Design pattern, as documented design experiences, can not only accelerate the development, but also improve the quality of software. This thesis explained the object-oriented design principles hidden behind design patterns afer analyzing and comparing 23 classical design patterns described by GoF, and then applied them to the implementation of communication software model to improve its quality, such as reliability, maintainability, portability, extensibility, reusability, and so on.