中文摘要：

策略提炼和策略，中突是解决基于策略的网络管理系统实现中两个最主要的难点问题．本文通过对基于策略的网络管理理论和访问控制技术的研究，利用访问控制列表（ACL），提出了一个基于策略的网络管理系统实现方案．主要介绍和描述了系统的整体框架及其实现机制；重点讨论了实现过程中的关键技术问题及解决方法，包括策略表示、策略提炼和策略，中突等问题；对策略冲突的解决方案进行了形式化描述，并通过模拟实验验证了本方案的可行性和有效性．

英文摘要：

Policy refinement and policy conflict resolution are two of the toughest issues in implementing a policy-based network management （PBNM） system. Based on a brief review of general PBNM theories and specific access control technologies, the paper proposed a novel policy-based network management model, which adopts XML as the high level policy description language, and uses the generalized access control list （ACL） as an intermediate refining mechanism, focusing on network security and QoS management. Some critical issues and their solutions, including policy representation, policy refinement, and policy conflict ＆ policy detection, are discussed. A formula representation of the policy conflict issue is given with several important inferences. The effectiveness and efficiency of the model is verified by the implemented prototype.