论文标题:P-NNI协议关键技术研究
Research On The Key Technology Of P-NNI Protocol
论文作者 应小凡
论文导师 刘增基,论文学位 硕士,论文专业 通信与信息系统
论文单位 西安电子科技大学,点击次数 85,论文页数 55页File Size2736k
2001-01-01论文网 http://www.lw23.com/lunwen_135390237/ ATM,P-NNI协议,QoS路由算法,分级网络,路由筛选机制
ATM,P-NNI protocol,QoS routing algorithm,Hierarchical Network,path filtrating method
ATM是宽带网络的关键技术，专用ATM网络节点间协议（P-NNI）是ATMForum的标准，因此，研究P-NNI协议具有十分重要的实际应用价值与学术价值。 本文给出P-NNI协议的总体功能框架，为进一步开发P-NNI产品奠定了一定的基础。同时，对ATM网络中的若干关键问题进行了深入的研究，并得到以下创造性成果：在Waxman网络模型的基础上提出了Efficient-Controllable网络模型，使生成的随机网络更接近实际的网络、更具有可操纵性，仿真效率更高，为本人的路由算法仿真提供了较好的实验平台；对通信网络QoS路由中的多约束条件下最小代价路由问题进行了研究，提出了适用于多种网络的Improved Multi-label算法，能够根据用户提出的速率因子等参数改善算法性能，灵活地在算法收敛速度与代价之间做出权衡，并提出一种新的路由筛选机制，及时将较差的路径淘汰，因此能够更灵活、效率更高地进行路由选择。此外，在文中证明了用改进的算法选出的路由是无环路的，进一步说明了Improved Multi-label算法具有较好的性能。在本人所提出改进的网络仿真模型中作了大量的仿真工作，证明改进的算法比原有的算法性能有了明显的改善，它效率更高、更灵活地解决了多约束条件下的最小代价路由这一难题；对ATM分级网络中关键节点的带宽需求与网络的可靠性作了深入的分析与研究，在分析过程中考虑到呼叫到达的多种典型分布，分别做了分析与比较，得到科学的结论。经过大量的仿真实验得到验证，证明理论分析所得到结论的正确性。分析与仿真结果表明在ATM分级网络中，关键节点的等级越高，承担的业务负载越重，相应的带宽需求越大，对网络可靠性的影响也越大。对避免ATM分级网络中瓶颈链与瓶颈节点的出现、提高QoS、改善网络性能有实际的指导意义。上述的路由算法及理论分析也适用于其它类型的通信网，具有一定的学术价值。 由于P-NNI协议非常复杂，而且协议中的许多内容还有待于进一步规范。例如：在分级结构下根据非精确信息的路由选择就没有统一的标准，分级选路是当前研究的热点也是很大的难点，是约束通信技术发展的瓶颈之一。在给出P-NNI的总体框架后如何更好地实现P-NNI还有许多难题需要解决，还需做大量的工作。
ATM is the key technology of broadband network, the P-NM protocol is the standard of ATM Forum on NNI. Therefore, the study of P-N7NI protocol has practical value and theory value. This paper presents the general function framework of P-NNI protocol, which may be the basis of further designing P-NNI product. Besides, studies of some key problems of ATM network are made, creative achievements are acquired as follows. Based on the Waxman network model, the Efficient-Controllable network model is presented, which is more similar to practical network, more controllable, and can improve the simulation efficiency, providing a good experiment environment for routing algorithm simulation; Study of communication network QoS routing is made, the Improved Multi-label algorithm is presented, which can improve the performance of algorithm according to the velocity parameter presented by the user .We can get the balance between the convergence velocity of the algorithm and the cost freely. A new path filtrating method is also presented which can delete the worst paths on time when routing, so we can route more freely and efficiently. Furthermore, we prove that paths routed using the improved algorithm are loopless, which further prove that the improved Multi-label algorithm has good performance. Many simulations are done on my network model, which prove that the new algorithm improve the performance of routing to a certain extent. The new algorithm solves the difficult problem of minimal cost routing with multiple constraints more flexibly and efficiently. Researches on the bandwidth requirement of different level key nodes and the reliability of network are done. Some typical kinds of calls are taken into account. Analysis and comparison among them are made. Simulations are made as well as mathematical analysis. The results of analysis and simulation show that the higher the level of key node (physical border node), the heavier service load the node should shoulder, so the bandwidth requirement of the key node is higher, the influence on the reliability of network is heavier, which makes important role to avoiding the arisen of bottleneck link and bottleneck node, improve the QoS and the performance of ATM hierarchical network. The algorithm and theory analysis are also applicable to other communication networks. Because the P-NNI protocol is very complex and need further standardized, implementing the P-NNI protocol still has many difficulty to deal with and many practical work to do. For example, the routing with inaccurate information under the hierarchical structure has no uniform standard, which is the hotspot and the difficulty of network technology research, is one of the bottlenecks that constrain the development of communication technology. After given the framework of P-NNI, we implementing the protocol still have many problems to resolve and much work to do.
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