Efficient large flow detection over arbitrary windows: an exact algorithm outside an ambiguity region

Being able to exactly detect large network flows under an arbitrary time win- dow model is expected in many current and future applications like Denial- of-Service (DoS) flow detection, bandwidth guarantee, etc. However, to the best of our knowledge, there is no existing work that can achieve exact large flow detection without per-flow status. Maintaining per-flow status requires a large amount of expensive line-speed storage, thus it is not practical in real systems. Therefore, we proposed a novel model of an arbitrary time window with exactness outside an ambiguity region, which trades the level of exactness for scalability. Although some existing work also uses some techniques like sampling, multistage filters, etc. to make the system scal- able, most of them do not support the arbitrary time window model and they usually introduce a lot of false positives for legitimate flows. Inspired by a frequent item finding algorithm, we proposed Exact-outside-Ambiguity- Region Detector (EARDet), an arbitrary-window-based, efficient, simple, and no-per-flow-status large flow detector, which is exact outside an ambi- guity window defined by a high-bandwidth threshold and a low-bandwidth threshold. EARDet is able to catch all large flows violating the high- bandwidth threshold; meanwhile it protects all legitimate flows complying with the low-bandwidth threshold. Because EARDet focuses on flow clas- sification but not flow size estimation, it demonstrates amazing scalability such that we can fit the storage into on-chip Static Random-Access Memory (SRAM) to achieve line-speed detection. To evaluate EARDet, we not only theoretically proved properties of EARDet above, but also evaluated them with real traffic, and the result perfectly supports our analysis

Mining frequent itemsets in a stream, in:

Abstract Mining frequent itemsets in a datastream proves to be a difficult problem, as itemsets arrive in rapid succession and storing parts of the stream is typically impossible. Nonetheless, it has many useful applications; e.g. opinion and sentiment analysis from social networks. Current stream mining algorithms are based on approximations. In earlier work, mining frequent items in a stream under the max-frequency measure proved to be effective for items. In this article, we extended our work from items to itemsets. Firstly, an optimized incremental algorithm for mining frequent itemsets in a stream is presented. The algorithm maintains a very compact summary of the stream for selected itemsets. Secondly, we show that further compacting the summary is non-trivial. Thirdly, we establish a connection between the size of a summary and results from number theory. Fourthly, we report results of extensive experimentation, both of synthetic and real-world datasets, showing the efficiency of the algorithm both in terms of time and space

Dynamic bandwidth allocation in ATM networks

Includes bibliographical references.This thesis investigates bandwidth allocation methodologies to transport new emerging bursty traffic types in ATM networks. However, existing ATM traffic management solutions are not readily able to handle the inevitable problem of congestion as result of the bursty traffic from the new emerging services. This research basically addresses bandwidth allocation issues for bursty traffic by proposing and exploring the concept of dynamic bandwidth allocation and comparing it to the traditional static bandwidth allocation schemes