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The end-to-end packet delay is an important performance parameter on the Internet, because it heavily affects the quality of realtime applications. Currently, however, because the packet transmission quality (e.g., transmission delay, jitter, packet loss) may vary dynamically, it is not easy to handle real-time traffic. For UDP-based real-time applications,(More)
Distributed denial-of-service attacks on public servers have recently become more serious. More are SYN Flood attacks, since the malicious attackers can easily exploit the TCP specification to generate traffic making public servers unavailable. To assure that network services will not be interrupted, we need faster and more accurate defense mechanisms(More)
Traffic matrix is essential to traffic engineering (TE) methods. Because it is difficult to monitor traffic matrices directly, several methods for estimating them from link loads have been proposed. However, estimated traffic matrix includes estimation errors which degrade the performance of TE significantly. In this paper, we propose a method that reduces(More)
A packet transmission delay is an important quality characteristic for various applications including real-time and data applications. In particular, it is necessary to investigate not only a whole distribution of the packet transmission delay, but also the tail part of the distribution, in order to detect the packet loss. In this paper, we analyze the(More)
Although anycast communication supports service-oriented addresses, many of its current definitions in IPv6 are unclear. Furthermore, since there are no protocol standards or even a consensus on controlling routing, intersegment anycast communications are not yet available. In this article we first review IPv6-based anycast communication. At present, there(More)
A rapid growth of the Internet and proliferation of new multimedia applications lead to demands of high speed and broadband network technologies. Routers are also necessary to follow up the growth of link bandwidths. From this reason, there have been many researches on high speed routers having switching capabilities. To have an expected effect, however, a(More)
1 はじめに インターネットアプリケーションにおける重要な通信品質 特性としてパケット転送遅延が挙げられる。実際に、TCP やストリーミングアプリケーションにおいて通信品質を考 慮した転送を行なうには、パケット転送遅延時間の予測が 必要であり、特にパケットロスを検知するためには、遅延 分布のすその部分の特性を明らかにすることが重要とな る。本稿では、まず測定ツールを用いてパケット転送遅延 を測定し確率分布関数による分布のモデル化を行う。統計 分析では、特に分布のすその部分に着目し、時間帯による 遅延特性の変化や確率分布のパラメータ推定のモデル化 における精度も明らかにする。その結果、パレート分布が 遅延分布のモデルとして最適であることを示す。さらに、 統計分析の結果をストリーミングアプリケーションに適用(More)
Many services have recently been offered based on a peer-to-peer (P2P) communication model. The robustness of the P2P network against frequent peer failure must be considered. Replication of the content is one of the most useful techniques to increase robustness. However, the overall effectiveness of replication is heavily dependent on the topology of the(More)
Secure virtualization is the enabling technique to protect both network providers and user services. Particularly, secure routing in the virtualized service domains is one of the key research areas that have not been explored in literature. In this paper, we present a new secure routing framework to address both network-centric and user-centric networking(More)
Software-defined Networking (SDN) is a new network architecture that decouples the control plane from the data plane. Scalability of the control plane with respect to network size and update frequency is an important problem that has been addressed by previous studies from a variety of viewpoints. However, the solutions found in these studies may be only(More)