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Abusive traffic caused by worms is increasing severely in the Internet. In many cases, worm-infected hosts generate a huge number of flows of small size during a short time. To suppress the abusive traffic and prevent worms from spreading, identifying these "superspreaders" as soon as possible and coping with them, e.g, disconnecting them from the network,(More)
— Unfairness among best-effort flows is a serious problem on the Internet. In particular, UDP flows or unresponsive flows that do not obey the TCP flow control mechanism can consume a large share of the available bandwidth. High-rate flows seriously affect other flows, so it is important to identify them and limit their throughput by selectively dropping(More)
— When a link or node failure occurs, flows are detoured around the failed portion, so the hop count of flows could change dramatically as a result of a failure. It is therefore important to evaluate the reliability of backbone networks from the viewpoint of flow hop length stability as well as network connectivity. In this paper, we analyze the possible(More)
We investigate how to detect network anomalies using flow statistics obtained through packet sampling. First, we show that network anomalies generating a huge number of small flows, such as network scans or SYN flooding, become difficult to detect when we execute packet sampling. This is because such flows are more unlikely to be sampled than normal flows.(More)
—When a link or node failure occurs in a network, flows are detoured and therefore the hop counts of the flows increase. This increase could drastically deteriorate the quality of a network. The flow hop length stability as well as network connectivity is important for network reliability. We investigate a network design method that improves stability and(More)
All-optical switching is of considerable interest, since it enables the construction of large-capacity networks with protocol- and bit-rate-independent transmission. In this paper, we investigate two all-optical architectures for backbone networks: the wavelength-routed network and the slotted wavelength-routed network. After proposing an optical path(More)