拒绝服务DoS（Denial of Service）攻击是互联网安全的最大威胁之一。低速率拒绝服务LDoS（Low-rate DoS）攻击是一种新型的DoS攻击，具有极强的隐蔽性，给检测和防御带来了困难。.本课题针对面向RED主动队列管理的LDoS攻击，从LDoS攻击下网络行为建模、LDoS攻击检测和LDoS攻击防御三方面展开研究：①将TCP拥塞控制机制和路由器队列管理算法关联分析，建立LDoS攻击下TCP拥塞窗口模型和路由器队列模型；②分析LDoS攻击下的队列分布，提取LDoS攻击特征，设计基于队列分布率的LDoS攻击检测方法；③设计基于队列稳定控制的LDoS攻击防御方法。通过上述研究，解决目前LDoS攻击领域存在的问题，达到有效检测和防御LDoS攻击的目的。

Denial of Service (DoS) attack is one of the greatest threats against Internet security. Low-rate DoS (LDoS) attack is a new type of DoS attack. With strong concealment, it is more difficult to detect and defend..This subject focus on the LDoS attack oriented to RED active queue management. Researches are expanded from three aspects: ①Network behaviors modeling. Through the related analysis of TCP congestion control mechanism and router queue management algorithm, the TCP congestion window model and the router queue model are built. ②LDoS attack detection. The queue distribution is analyzed to extract LDoS attack characteristic, and then a new detection approach is designed based on queue distribution rate. ③LDoS attack defense. A new LDoS attack defense approach is proposed based on queue stability controlling technology. Through the above researches, this subject tries to solve the existing problems in LDoS attack field, and achieves the goal of effectively detecting and defending LDoS attack.