The long-tailed distribution characterizes many Internet traffic properties which are often modeled by Lognormal distribution, Weibull or Pareto distribution theoretically. However, it is rather difficult to directly apply these models in traffic analysis and performance evaluation studies due to their complex representations and theoretical properties. This paper proposes a Hyper-Erlang Model (Mixed Erlang distribution) for such longtailed network traffic approximation. It fits network traffic with long-tailed characteristic into a mixed Erlang distribution directly to facilitate our further analysis. Compared with the wellknown hyperexponential based method, the mixed Erlang model is more accurate in fitting the tail behavior and also computationally efficient. Further investigations on the M/G/1 queueing behavior also prove the efficiency of the Mixed Erlang based approximation.

Collecting network traffic is becoming a more challenging task in passive network measurement due to the rapid growth of link speed. Flow-based network traffic capture and storage provides an efficient way for high-speed network measurement. The paper concentrates on the flow detection issue which is also the premise for further flow-based traffic analysis and modeling in such challenging environment. Based on the statistical investigation of the correlations between flow size and the maximum packet interarrival time within a flow, we obtain the empirical conditional distribution functions for some popular TCP protocol-based application flows, and then propose a Probability-Guaranteed Adaptive Timeout algorithm (PGAT) for flow termination decision. The assessment criteria for flow termination decision algorithm is systematically developed. Comparisons on flow generation ratio, flow intact ratio, and mean flow extra retaining time metrics indicate that the PGAT algorithm can obtain more attractive performance than other related works.

如何保证各网络设备协议实现的一致性，是保证各设备可以互联、互操作的关键。文中在介绍OsPFv3协议的基础上，设计并实现了该协议一致性测试系统。根据系统支持多端口的特性，提出一种改进的针对中继系统的一致性测试方法，克服了原有穿越式测试方法中测试系统之间的同步和协调问题。利用该系统对开放源码的路由软件包zebra进行了测试，结果表明在数据库描述包的MTu字段处理上和RFc2328存在不一致。