论文部分内容阅读
Detecting traffic anomalies is essential for diagnosing attacks.High-Speed Backbone Networks (HSBN) require Traffic Anomaly Detection Systems (TADS) which are accurate (high detection and low false positive rates) and efficient.The proposed approach utilizes entropy as traffic distributions metric over some traffic dimensions.An efficient algorithm,having low computational and space complexity,is used to estimate entropy.Entropy values over all dimensions are collected to form a detection vector for every sliding window.One class support vector machine classifies all detection vectors into one of two groups:abnormal vectors and normal vectors.A Multi-Windows Correlation Algorithm (MWCA) calculates comprehensive anomaly scores observed in a sequence of windows in order to reduce false positive rates and obtain high detection rates.Some real-world traffic traces have been used to validate and evaluate the efficiency and accuracy of this system through three experiments.In Experiment 1,the estimating algorithm of entropy which costs less memory and runs faster than traditional algorithms is more suitable for detection anomalies.In Experiment 2,the classification and correlation algorithms can improve the detection accuracy significantly.Experiment 3 compares the subject system and three well-known systems.Ours system is the most accurate one.Those results have indicated that the proposed system significantly improves the accuracy and efficiency.