金田の論文

生澤 満, 吉澤 聡, 三村 到, 金田 泰, 大槻 兼市, 電子情報通信学会 1999 年 通信ソサイエティ大会，SB-6-4, 1999, IEICE により出版.

Kanada, Y., Ikezawa, M., Miyake, S., and Atarashi, Y., draft-kanada-diffserv-qospifmib-00.txt, Internet Draft, November 1999.

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[ Slides used in 46th IETF: Configuration Management BOF, Diffserv WG, and RAP WG (not recommended) ]

要約: This document describes a QoS PIF MIB (Quality-of-Service Programming-Interface Management-Information-Base) to be used as an SNMP-based programming interface for routers. This MIB is intended to be a programming interface for router QoS functions, especially DiffServ-related [RFC2475] functions including packet scheduling (queuing), dropping, and metering that must be modular and concisely described. Traffic-conditioning rules and metering rules for DiffServ-related functions are defined modularly by using "virtual flow labels" and exclusive conditions in rules, and new classifications for packet-scheduling and packet-dropping functions are introduced. This document focuses on satisfying the requirements on programming interfaces or programming languages for router control. Thus, the focus is different from that of DiffServ MIB [DSMIB] or QoS PIB [QoSPIB].

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会 ネットワーキング・アーキテクチャ・ワークショップ 10 周年記念大会, pp. 106-113, IEICE, 2000.

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要約: To realize internet-protocol-based QoS-assured networks, using differentiated services under policy-based networking is a promising approach. A QoS policy server must work in multi-vendor environment. To use standard protocol, such as COPS or SNMP, between the policy server and routers is not sufficient, but also to define and to standardize high-level syntax and semantics, i.e., a language, is required for interoperability. This paper describes the outline of a rule-based language for this purpose. Policy rules can be defined in the policy server and can be deployed to routers or router proxies using this language through an appropriate protocol such as COPS, SNMP, or IIOP. The language consists of several types of rules, i.e., matching, policing (or metering), marking, discarding, and scheduling types, and linkage labels that connects rules. A MIB and/or PIB that simulates the language is also explained in this paper. The language will be implemented in near future.

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., International Workshop on Quality of Service 2000 (IWQoS 2000), pp. 161-163, June 2000.

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要約: Network node functions, such as QoS or the security functions of routers, are becoming increasingly complex, so programs, not only configuration parameters, are required to control network nodes. In a policy-based network, a policy is defined at a policy server as a set of rules that deployed at network nodes where it must be translated into an executable program or parameters. Thus, a policy must be represented by a form in which the syntax and semantics are clearly defined, and which can be mechanically translated into an executable program. This is possible if the policy is written in an appropriate rule-based programming language. This paper describes such a language in which functions required for DiffServ can be specified for the interface between a policy server and network nodes. In this language, a policy rule can be composed using predefined primitive building blocks and control structures.

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., 2nd International Working Conference on Active Networks (IWAN 2000), Lecture Notes in Computer Science, No. 1942, pp. 195-210, Springer, October 2000,
http://dx.doi.org/10.1007/3-540-40057-5_15

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要約: Policy-based networks can be customized by users by injecting programs called policies into the network nodes. So if general-purpose functions can be specified in a policy-based network, the network can be regarded as an active network in the wider sense. In a policy-based network, two or more policies must often cooperate to provide a high-level function or policy. To support such building-block policies, two architectures for modeling a set of policies have been developed: pipe-connection architecture and label-connection architecture. It is shown that rule-based building blocks are better for policy-based network control and that the label-connection architecture is currently better. However, the pipe-connection architecture is better in regards to parallelism, which is very important in network environments.

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会 情報ネットワーク (IN) 研究会, 信学技法, 100-378, IN 2000-102, pp. 47-54, 2000-10.

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要約: ポリシーベース・ネットワークにおいては，高水準の機能あるいはポリシーを 実現するためにしばしば 2 個以上の低水準のポリシーをくみあわせる必要がある． このような部品化されたポリシーをサポートするために，複数のポリシーを モデル化するための 2 つのアーキテクチャを開発した． それらはパイプ結合 アーキテクチャとラベル結合アーキテクチャである． 規則ベースの部品が ポリシーベース・ネットワーク制御にとってすぐれていること，そして ラベル結合アーキテクチャが現在のところはよりよいことがわかった． しかし， また，ネットワーク環境においては非常に重要な並列性という点においては パイプ結合アーキテクチャのほうがすぐれていることがわかった．

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., Workshop on Policies for Distributed Systems and Networks (Policy 2001), Lecture Notes in Computer Science, No. 1995, Springer, pp. 171-184, January 2001, http://dx.doi.org/10.1007/3-540-44569-2_11

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要約: To control complicated and decomposable networking functions, such as Diffserv, two or more policies must cooperate. Combining two or more mutually dependent policies for a specific purpose is called policy combination. Methods of passing information between combined policies can be classified into real tags and virtual tags, or labels and attributes. Policy combinations can be classified into concatenation, parallel application, selection, and repetition. Explicitly specifying policy combinations makes policy systems semantically clearer and better suited to general use, extends the range of functionality, and improves the possibility of optimization. If policy combinations can be specified in a policy system, two types of policy organizations can be distinguished: homogeneous and heterogeneous. Heterogeneous organization is more service-oriented and seems to meet service-management requirements, but homogeneous organization is more device-oriented and may provide better performance.

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., 7th IFIP/IEEE International Symposium on Integrated Network Management (IM 2001), pp. 545-560, May 2001, http://dx.doi.org/10.1109/inm.2001.918065

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要約: Because higher- and lower-level policies do not necessarily correspond one to one, a higher-level network policy may have to be translated into two or more lower-level policies, and two or more cooperating higher-level policies may have to be translated into one lower-level policy. The former transformation is called a policy division, and the latter transformation is called a policy fusion. These transformations can be performed mechanically under restricted conditions as described in this paper. However, in general, they are very complicated and the restrictions cannot be eliminated completely mainly because of existence of multiple packet classifiers in a set of policies. Thus, this paper concludes that they should not be introduced if it is possible. The policy division and fusion can be avoided in certain cases, but they will not probably be able to be avoided in general. If so, the problem should be solved or relaxed by removing harmful classifiers by introducing virtual flow labels and by further studies. In addition, we may have to find a better method to control network devices than policies in the current sense.

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y. and O'Keefe, B. J., Asia-Pacific Network Operations and Management Symposium 2001 (APNOMS 2001), September 2001, (poster paper, presentation cancelled).

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要約: Policies sometimes have to be combined and applied in cooperation to represent such programmable and customizable network functions as Diffserv. In the OpenView PolicyXpert and JP1/PolicyXpert policy servers, three types of policies and three types of virtual flow labels, to connect the policy rules, are defined for Diffserv. The combination of these policies allows the representation of complex Diffserv policies and the separation of service and subscriber policies. Diffserv policies and virtual flow labels make this possible. However, the careful design of Diffserv policies has enabled simple Diffserv policies to be represented in a simple form.

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, ブライアン・オキーフ, 電子情報通信学会 情報ネットワーク・ネットワークシステム (IN / NS) 合同研究会，2002-3.

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要約: ネットワークのポリシー制御において，Diffserv のようなプログラムし カスタマイズすることが可能なネットワーク機能を表現するために， 複数のポリシーをくみあわせる必要が生じることがある． PolicyXpert というポリシーサーバにおいて，3 種類のポリシーと，ポリシーを接続するための 3 種類の仮想フローラベル (VFL) とを設計・実装した．ポリシーのくみあわせに よって複雑な Diffserv ポリシーが表現可能になる． また，ポリシーをくみあわせる ことにより，DSCP にもとづくサービスクラスのサブクラスの定義が可能になり， サービスポリシーと加入者ポリシーとの分離が可能になっている． しかも， Diffserv ポリシーを慎重に設計したため，単純な Diffserv ポリシーは単純な かたちであらわせるようになった．

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会 2002 年総合大会，2002-3.

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要約: (なし)

Kanada, Y., and Yazaki, T., Communications Quality and Reliability 2002 (CQR 2002), pp. 12-16 2002.

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要約: In policy-based networks, two or more policies often have to cooperate because combined and customized network functions must be controlled using policies. Two types of policy trans-formation, policy fusion and policy division, are sometimes required to implement cooperating policy systems on high-performance hardware routers. Policy fusion transforms two or more policies into one, and policy division transforms a policy into two or more policies. These transformations causes a problem that the original policies must usually be strongly constrained to allow these transformations. This paper shows a method for resolving restrictions on the division of QoS policies by a software-hardware integration, i.e., by implementing virtual flow labels (flow IDs) in hardware and by dividing a policy and deploying the policies onto two filter blocks. We have developed a policy agent (PEP) and a gigabit router integrated by using this method. Both high-performance and flexibility are achieved by this integration.

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., 3rd International Workshop on Policies for Distributed Systems and Networks (Policy 2002), pp. 236-239, June 2002, http://dx.doi.org/10.1109/policy.2002.1011316

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要約: This paper proposes a method, called the policy-extension-by-policy method, for quickly and dynamically adding policy classes with new functionality to policy servers and agents. In this method, users can add a new policy class to the policy server by using policy-definition (PD) policies, and they can define a method to translate a policy of the new class and to send to network nodes of different vendors through various types of device interfaces, such as CLI, MIBs, PIBs, APIs or hardware tables, by using policy-embedding (PE) policies. A PE policy also enables translating a policy of an existing class and sending the result to a new type of network node. PE policies contain command templates and methods for filling the templates. A program interpreter is embedded in policy agents to make flexible policy-to-configuration translation possible. A prototype system and example policies, i.e., access control, Diffserv, and VPN policies, were developed.

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y. and O'Keefe, B. J., Journal of Network and Systems Management, Vol. 11, No. 3, pp. 253-275, 2003.

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要約: We developed two rule-based building-block architectures, i.e., pipe-connection and label-connection architectures, for describing complex and structured policies, especially network QoS policies. The latter is focused on in this study. The relationships or connec-tions between building blocks are specified by the da-taflow and control flow between them. The dataflow is specified by tags, including virtual flow labels (VFLs), which are data attached to "outside packets". The con-trol flow can be classified and specified by four control structures: concatenation, parallel application, selection, and repetition. We have designed fine-grained and coarse-grained building blocks and methods for specify-ing dataflow and control flow in differentiated services (Diffserv), and implemented the coarse-grained ones in a policy server. Two cases of building-block use are de-scribed, and we concluded that there are five advantages of building-block-based policies, i.e., expressibility, uni-form semantics, simplicity, flexibility, and management-task-oriented design. We also developed techniques for transforming building-block policies into executable ones, which are called policy division and fusion.

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会 インターネットアーキテクチャ (IA) 研究会, 2003-10.

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要約: 電話にかわるべき音声コミュニケーション・メディアの確立をめざした研究の 一部として，多者間通信が可能な常時接続型コミュニケーショ ン・メディア voiscape のアーキテクチャとプロトタイプを開発した． Voiscape においては 3 次元オーディオ技術によってつくられた仮想的な "音の部屋" を使用する． ユーザがマウスをつかって音の部屋内を移動すると，プレゼンスサーバを介して 部屋内の位置などのプレゼンス情報が部屋内の他のユーザにつたえられる． 相手にちかづいたり相手からとおざかったりすると，あらかじめ端末において 定義されたポリシーにしたがって，SIP を使用して自動的に通信セッションの 開始・終了などの動作がとられる． このポリシーベース・セッション制御に よってプライバシー保護や通信量削減が可能になる． 接続開始を要求する際に 相手からも同時に接続開始を要求されることが頻繁におこりうるので，2 重に接続したり "話し中" になったりせずに接続が確立する方法を くふうしている．

研究テーマ紹介: voiscape

金田 泰, 電子情報通信学会 マルチメディアと仮想環境研究会, 2003-10.

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要約: 電話にかわるべきコミュニケーション・メディア voiscape の概念を提案する． Voiscape は，3 次元オーディオ技術による仮想的な "音の部屋" をユーザ間で共有し，そのなかを自由に移動してさまざまなひとと会ったり わかれたりしながら多者間のコミュニケーションがおこなえるウェアラブルな メディアである． プレゼンスや周縁的情報の伝達を可能にし，電話におけるような 1 対 1 の会話から従来のメディアではできなかったさまざまなかたちの コミュニケーションまでをカバーすることによって，つながり感・安心感の 共有や暗黙知の共有も実現されるだろう． この論文では voiscape の使用場面や 手順についてのべ，PC 上に開発した voiscape のプロトタイプについてものべる． プロトタイプ上ではユーザは前方の様子を 3 次元グラフィクスによって 確認しながらマウスをつかって部屋内を移動することができる．

研究テーマ紹介: voiscape

金田 泰, 情報処理学会 マルチメディア通信と分散処理研究会, 2004-3.

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要約: 電話にかわるべき音声コミュニケーション・メディア voiscape の確立をめざし て研究をおこなっている． Voiscape においては 3 次元オーディオ技術によっ てつくられた仮想的な "音の部屋" を使用するが，音声通信と 3 次元音声にく わえて 3 次元グラフィクスを使用するプロトタイプを PC 上に開発した． この プロトタイプにおいては音声のキャプチャと通信のために JMF (Java Media Framework)，3 次元音声 / グラフィクスのために Java 3D を使用した． 開発 前はこれらの API をつなげば必要な基本機能がほぼ実現できるとかんがえてい たが，実際にはこれらを直接つなぐことはできず，3 次元音声のためには Java 3D のインタフェースをとおして OpenAL を使用した． また，プロトタイプにお いては音質劣化や遅延などの問題を容易に解決することができなかったが，試行 をかさねてこれらの問題をほぼ解決した．

研究テーマ紹介: voiscape

Kanada, Y., 2nd IASTED International Conference on Communication and Computer Networks (CCN 2004), 2004-11.

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要約: A new voice communication medium, which the author calls "voiscape", will probably appear in near future. Voiscape shall have much improved user interface than the conventional voice communication systems, i.e., telephone and conference systems, and be based on the IP-based conferencing and spatial audio technologies. The author has developed a prototype toward voiscape, which has made a step toward solving two problems of the conventional systems i.e., complicated and restricted conference control and lack of crossed-over multi-context support, by introducing two features. The first function is the virtual-location based communication; i.e., the users can talk with other users and move, in a way similar to face-to-face conversation, in a virtual auditory space created by spatial audio technology without explicit session and floor control. The second function is personalized policy-based communication control; i.e., the users can specify communication policies that protects their privacy and reduce required resources. This function is enabled by a distributed policy-arbitration mechanism. Experiments showed that the basic mechanisms and the policy-based control with a simple policy worked well.

研究テーマ紹介: voiscape

Kanada, Y., 15th ACM International Workshop on Network and Operating System Support for Digital Audio and Video (NOSSDAV 2005), pp. 45-50, June 2005, http://dx.doi.org/10.1145/1065983.1065996

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要約: An improved prototype of the "voiscape" voice communication medium has been developed and subjectively evaluated. Voiscape enables natural and seamless voice communication by using sound to create a virtual "sound room" in which people, who are repre-sented by different sounds, can move freely. It features low-delay motion-tracking spatial audio with simulated early reflections that produce out-of-head sound localization and sound distance expression. It also features virtual-location-based selective communication: a user can walk freely in the sound room using a map- and cursor-key-based user-interface and can select whom to talk to or which sound sources to listen to. A third feature is SIP-presence-event-notification (SIMPLE)-based sound room management: when users move, their locations and directions are distributed using SIP SUBSCRIBE/NOTIFY messages. The combination of these features creates a natural voice-communication space in which two or more parallel conversation contexts can coexist. Limited, subjective testing by around 200 people showed that this medium can be used for cocktail-party-like conversation; i.e., users could distinguish parallel conversations by paying attention to or by moving toward one of them.

研究テーマ紹介: voiscape

金田 泰, 電子情報通信学会 応用音響 (EA) 研究会, 2005-6.

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要約: 3D 音響技術によってつくられた仮想的な "音室" 内を移動して相手を選択しつつ 会話ができるコミュニケーション・メディア voiscape を開発している． Voiscape の第 2 のプロトタイプ VPII においては，FIR 法によって低遅延な HRTF フィルタ計算をおこなうとともに，移動可能な範囲としての音室を 音響計算上の部屋とみなし，その壁による初期反射をシミュレートした． この初期反射によって音の頭外定位と距離感の表現を可能にした． また，ユーザの移動を追跡し必要な補間処理をおこなった． これによって，話者識別が容易で，複数の会話コンテクストが共存することができ， また音室内の移動が自然でノイズがすくない音声コミュニケーション環境を実現した．

研究テーマ紹介: voiscape

Kanada, Y., Asia-Pacific Network Operations and Management Symposium 2005 (APNOMS 2005), September 2005.

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要約: A method for conference-room management for an auditory-virtual-space-based voice-communication medium called voiscape and a voice-communication system prototype called VPII, which used this method, were developed. With this method, conference rooms (called sound rooms) are managed through SIP and SIMPLE (a presence-related event-notification mechanism). A user can not only obtain a room list and enter (select) or exit from a room, but can also create, modify, or delete rooms by SIMPLE messaging. Rooms, users, and objects are managed by their "soft state"; i.e., they are deleted when a time out occurs. Users are informed of room membership, presence of a user, e.g., location and direction in the room, and presence of an object in the room by SIMPLE messaging, i.e., by SUBSCRIBE, NOIFY, and PUBLISH requests. To reduce the messaging overhead, the partial notification mechanism of SIMPLE is used in VPII.

研究テーマ紹介: voiscape

Kanada, Y., 13th ACM International Conference on Multimedia, pp. 794-795, November 2005, http://dx.doi.org/10.1145/1101149.1101319

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要約: We are developing a new voice communication medium called voiscape. Voiscape enables natural and seamless bi-directional voice communication by using sound to create a virtual sound room. In a sound room, people can feel others' direction and distance expressed by spatial sounds with reverberations, and they can move freely by using a map of the room. Voiscape enables multi-voice-conversations. In a virtual market place that will be realized by voiscape, people can not only buy goods or information but also enjoy talking with merchants and people there. In this demo, a voiscape prototype called VPII is used for realizing such an environment. Unfortunately, because prerecorded voices are used in this demo, the participants cannot talk with merchants. However, the participants can talk each other with small end-to-end latency (less than 200 ms) and will feel the atmosphere of the virtual market place. Prerecorded people and merchants talk each other in English, Japanese and Chinese in parallel and with crossovers, and participants can virtually walk among them and can selectively listen one voice or hear multiple voices at once.

研究テーマ紹介: voiscape

金田 泰, 電子情報通信学会 コミュニケーションクオリティ (CQ) 研究会, 2007-7.

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要約: RSVP や NSLP にちかいプロトコルによって端末からつたえられる QoS 要求をコア網で集約してスケーラブルな QoS 保証を実現する方式を設計・ 試作した． 要求はポリシールーティングとアウトソース型のプロトコル によってポリシーサーバにつたえられる． ポリシーサーバが要求をもと にトラフィック量を予測してコアノードのキュー (WFQ) の帯域分割を 制御する． このコアノードの制御の効果を L3 スイッチ GS4000 に MMPP モデルにもとづくバースト性トラフィックをとおして評価した． その結果，大量の会話ビデオ・トラフィックとストリーミング・トラ フィックとがあるときに，WFQ における前者のウェイトを後者より たかめれば，しかるべき条件のもとでは両者ともに満足させられること がわかった．

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会 応用音響 (EA) 研究会, EA2007-42, 2007-8.

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要約: voiscape は仮想音響空間内を自由に移動しながら会話できるコミュニケーション・メディアである． そのプロトタイプ VPIIQ (Voiscape Prototype 2 Q) を使用して，ネットワーク・ポリシーのちがいによる QoS のちがいがあたえる効果に関する主観評価を実施したところ，音源方向等をあてる位置判定実験において，予想とちがって QoS がひくいときのほうがやや正答率がたかかった． また，位置判定実験においては被験者が移動・回転の操作をしないときよりそれをしたときのほうが正答率がたかかったが，話者判定実験においては逆の結果がえられた．

研究テーマ紹介: voiscape

金田 泰, 電子情報通信学会 通信ソサイエティ大会, 2007-7.

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要約: NGN の目標とされている端点間 (end-to-end) QoS 保証を実現するコア網のためのスケーラブルな QoS 技術の開発をめざしている． 2006 年度は次世代バックボーンにおいて有効なポリシーベースのトラフィック制御法の発見を目標として，QoS 保証方式の開発，プロトタイプの開発と評価実験とをおこなった．

開発した方式においては，RSVP や NSLP にちかいプロトコルによって端末からつたえられる QoS 要求をコア網で集約してスケーラブルな端点間 QoS 保証を実現する． 上記のプロトタイプにおいてこの要求はポリシールーティングとアウトソース型のプロトコルによってポリシーサーバにつたえられ，ポリシーサーバが要求をもとにエッジノードにポリシングとマーキングの設定をおこなうとともに，トラフィック量を予測してコアノードのキューを制御する．

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., 未出版 (2008-4).

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要約: Real-time and multimedia applications require an end-to-end QoS guarantee, and various types of applications require various QoS conditions. A DiffServ network should guarantee different QoS conditions for different types of communications. In this paper, the effect of traffic control in a DiffServ core network is experimentally evaluated using bursty traffic generated by an MMPP (Markov-Modulated Poisson Process) model. The situation to be simulated is that there are hundreds of conversational video streams that are delay-sensitive and hundreds of streaming videos that are loss-sensitive. If there are bandwidth-sharing queues such as those follow WFQ (Weighted Fair Queuing) in the core no-des and the two types of video traffic are assigned to two of the queues, the requirements of both types of traffic can be satisfied in a better way (a more efficient way) by assigning a larger weight to the queue for the conversational video. In our experiment, the optimum ratio of the weights was ap-proximately 1.3 when the traffic rates were the same. The optimum weight shares depend on the nature of the traffic, especially the burstiness.

Kanada, Y., The International Conference on Information Networking 2008 (ICOIN 2008), I-1, January 2008, http://dx.doi.org/10.1109/icoin.2008.4472753

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[ IEEExplore 論文ページ ]

要約: Real-time and multimedia applications require an end-to-end QoS guarantee, and various types of applications require various QoS conditions. A DiffServ network should guarantee different QoS conditions for different types of communications. In this paper, the effect of traffic control in a DiffServ core network is experimentally evaluated using bursty traffic generated by an MMPP (Markov-Modulated Poisson Process) model. The situation to be simulated is that there are hundreds of conversational video streams that are delay-sensitive and hundreds of streaming videos that are loss-sensitive. If there are bandwidth-sharing queues such as those follow WFQ (Weighted Fair Queuing) in the core no-des and the two types of video traffic are assigned to two of the queues, the requirements of both types of traffic can be satisfied in a better way (a more efficient way) by assigning a larger weight to the queue for the conversational video. In our experiment, the optimum ratio of the weights was ap-proximately 1.3 when the traffic rates were the same. The optimum weight shares depend on the nature of the traffic, especially the burstiness.

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会ネットワークシステム (NS) 研究会, 2009-4-16.

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[ 論文 PDF ファイル (C) IEICE ]

要約: アプリケーションによる資源要求と NetFlow によってえられる DiffServ クラスごとのトラフィック計測結果の両方にもとづくアドミッション制御法を開発した． この方法を使用したポリシーサーバのプロトタイプを開発し，シミュレートされた音声トラフィックを使用して実験した． その結果，この方法を使用すればひくい計測負荷で帯域使用率をたかめることができ，呼損を減少させられることがわかった． On/off モデルを使用したシミュレーションの結果，興味ぶかいが害をなしうるダイナミクスが観察された． すなわち，このアドミッション制御法においてはパラメタの値によって発振や 100～150 分間にわたる変化，帯域のオーバーシュートなどの現象がおこることがわかった． これらの現象をおさえてアドミッション制御を適切に動作させられるおよそのパラメタ値の範囲をもとめることができた．

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., 5th Advanced International Conference on Telecommunications (AICT 2009), 2009-5-25, http://dx.doi.org/10.1109/aict.2009.16 [新型インフルエンザのために発表はキャンセルされた.]

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要約: A method of admission control based on both resource requests by applications and class-based traffic mea-surement results was developed. In this method, a wide range of admission-control policy can be realized by adjusting three parameters, , , and . A policy-server prototype using this method and simulated voice traffic was used in traffic measurements. The measurements results show that the proposed method improves bandwidth usage and decreases call-blocking ratio while incurring low measurement load. Interesting but possibly harmful dynamics (i.e., system behavior) were observed by the simulations using traffic generated by an on/off model. That is, this admission-control method may cause oscillation or long-term evolution that lasts for 100 to 150 minutes, and it may also cause bandwidth “overshooting”. The range of parameters with which such effects can be properly suppressed and the admission control correctly works was experimentally obtained.

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 電子情報通信学会情報ネットワーク (IN) 研究会, 2009-5-21.

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要約: ユーザが経験する通信の体感品質すなわち QoE に関する要求をユーザが入力し，その要求をネットワークにおいて満足させるための機構を提案する． QoE 要求は QoS にマップされ，アドミッション制御やネットワーク・ノードへの設定を通じて満足される． 要求のためにソフト・ステートのプロトコルを使用することによって，サービスの開始，延長，中止などを統一的にあつかうことができる． この機構の一部をプロトタイプにくみこみ， 階層化シェイパーつきのネットワーク・ノードを使用して動画ストリーミングに関する実験をおこなった結果，QoE 要求が満足されることを確認した．

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., and Tarui, T., 10th International Conference on Networks (ICN 2011), 2011-1-24.

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[ ThinkMind Paper page ]
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要約: Two network-virtualization architectures, namely, network segmentation and network paging, were investigated. They are analogical to two memory-virtualization architectures: segmentation and paging. Network paging, which is relatively new and is based on a type of network-address translation (NAT), is focused on. This architecture requires smaller packet size and has several more advantages over the conventional architecture (i.e., network segmentation). Intranet- and extranet- type communication methods based on this architecture are described. An address translators is placed at each edge router in the WAN and used to evaluate client-server communication under wide-area virtual-machine (VM) live migration as a case of extranet-type communication.

研究テーマ紹介: ネットワーク仮想化

Kanada, Y., and Tarui, T., 25th International Conference on Information Networking (ICOIN 2011), 2011-1-28, http://dx.doi.org/10.1109/icoin.2011.5723191

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[ IEEExplore 論文ページ ]

要約: In cloud-computing environments, migration of virtual machines (VMs) between data centers can solve many problems such as load balancing and power saving. One of the difficulties in wide-area migration, however, is the “address-warping” problem, in which the address of the VM warps from the source server to the destination server. This confuses or complicates the status of the WAN, and the LANs connected to the WAN. We propose two solutions to this problem. One is to switch an address-translation rule, and the other is to switch multiple virtual networks. The former is analogous to paging in memory virtualization, and the latter is analogous to segmentation. The “network-paging” based method is described and our evaluation results are shown. It took less than 100 ms in average to switch from the source to the destination server using this method.

研究テーマ紹介: ポリシーにもとづくネットワーキング

金田 泰, 垂井俊明, 情報処理学会論文誌, Vol. 52, No. 3, pp. 1-17, 2011.

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[ PDF 版論文へのいりぐち (IPSJ) ]

要旨: ネットワーク仮想化は，ひとつの物理的なネットワーク上で多様なサービスを相互に干渉せず実現し，かつ単純にプログラムしカスタマイズすることを可能にする． ネットワーク仮想化は，IP，VLAN，あるいは NAT を使用するなど，多様な機構によって実現できる． 我々はこれらの実現手段に依存しない統一的な仮想ネットワークのモデルをつくり，そのモデルによって記述した仮想ネットワークを基本的に変更せずに多様な実現手段のネットワーク上に展開可能にすることをめざしている． この論文では仮想ネットワークのモデルとその主要な部品を定義し，それによって広域ライブ・マイグレーションのための仮想ネットワークを記述し，さらにそれをネットワーク・パーティション (VLAN による VRF) とアドレス・マッピング (NAT) という 2 つの実現方法による仮想ネットワークに展開できることを示す． この方法を仮想ネットワーク設定プロトタイプを新規開発して評価した． その結果，アドレス範囲指定やルーティング・パラメタの指定は実現手段ごとに変更する必要があったが，モデル記述の主要部分は共通化できた．

研究テーマ紹介: ポリシーにもとづくネットワーキング

Kanada, Y., Tarui, T., and Shiraishi, K., IFIP/IEEE International Symposium on
Integrated Network Management (IM 2013), 2013-5.
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[ 論文 PDF file ]
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要約: A method for federating multiple network-virtualization platforms by creating and managing slices (virtual networks) is proposed. A cross-domain slice can be created, deleted, or modified by sending a slice specification to the domain controller (network manager) of one domain. The specification is then propagated to other domains. Two chal­lenges were addressed while this method was developed. The first challenge is to enable federation among multiple domains that do not support federation functions by only adding a few components without modification of the existing network-virtualization-platform architecture. A domain-dependent specification of a slice, containing a pseudo virtual node that encloses a part of the slice specification in the other domains, is used, and this part is handled by a proxy node that represents another domain and a control component that implements a federation API to create a cross-domain slice. The second challenge is to enable manageable non-IP (arbitrary-format) data communication on a cross-domain slice. For an inter-domain communication, underlay VLAN parameters including MAC addresses are negotiated in advance and data packets on a slice are tunneled between gateways in these domains. The proposed federation method was implemented on two network-virtualization platforms, federation between two homogeneous domains was successfully demonstrated, federation perfor­mance was measured, and several issues on functional restrictions and implementation difficulty were found.

研究テーマ紹介: ネットワーク仮想化

金田 泰, 電子情報通信学会 第 7 回 ネットワーク仮想化時限研究会, 2013-7.
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[ Paper PDF file ]
[ Slides ]

Abstract: ネットワーク・プロセッサは高性能でプログラマブルなネットワークのためにひろく使用されている． しかし，ネットワーク・プロセッサのプログラムは移植性と開発者数がかぎられ，開発コストが高い． この問題を解決するためにオープンで高級かつ移植性のあるプログラミング言語 CSP とそのための開発環境 +Net を開発した． この環境においては，パケットの高速処理に必要な SRAM と DRAM のつかいわけをプログラマにできるだけ意識させずに高 いスループットがえられるようにした． ネットワーク・プロセッサ Cavium Octeon のためのプロトタイプを実装し，ネット ワーク仮想化基盤の一部を使用して評価した結果，かんたんなプログラムでワイヤレートにちかい 7.5 Gbps 以上の 性能をえた．

研究テーマ紹介: Network virtualization

Kanada, Y., and Tarui, T., Network Virtualization Symposium 2013, September 2013.
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[ ポスター PDF ファイル ]

要約: VNode enabled mutually independent evolution of programmers and redirectors. In this presentation, a method for evolving VNodes and developing new species of virtual links by using both control and data plug-ins and a publicly available testbed is proposed.

研究テーマ紹介: ネットワーク仮想化

Kanada, Y., 2nd International Workshop on Network Management and Monitoring (NetMM 2014), May 2014, http://dx.doi.org/10.1109/waina.2014.112
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Abstract – A network processor (NP) usually contains multiple packet processing cores (PPCs) and a control processing core (CPC), and the synchronization and communication between CPC and PPCs, which is required for controlling an NP, is very complex. To reduce the complexity, a method for controlling packet processing in NPs by using PPCs is proposed. By means of this method, complex control messages are partially processed and divided into simplified control packets by a CPU outside the NP chip, and these packets are sent to a control-processing PPC. The control-processing PPC controls data-processing PPCs by using data-exchange mechanisms, such as a shared memory or an on-chip network, which are more uniform and simpler than those between a CPC and PPCs. This control method is applied to a virtual-link controlprocessing task and packet-processing tasks in a network node with a virtualization function. Both tasks are described by a hardware-independent high-level language called “Phonpl,” and communication between the PPCs is programmed following normal and uniform shared-memory semantics. As a result, programming the control-processing task and porting the program become much easier.

研究テーマ紹介: ネットワーク仮想化

Yasusi Kanada, ACM SIGPLAN Workshop on Memory Systems Performance and Correctness (MSPC 2014), poster, June 2014.
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[ ポスター写真 ]
[ ポスター原稿 ]

研究テーマ紹介: ネットワーク仮想化

Kanada, Y., 29th edition of the International Conference on Information Networking (ICOIN 2015), January 2015, http://dx.doi.org/10.1109/ICOIN.2015.7057953.
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[ シミュレータのプログラム ]

Abstract – Many commercial and open-source network simulators are available; however, most of them are not suited for novices in college and school education or learning. Moreover, although Ethernet has recently become much more important, simulators that can be used for this purpose is rare because most simulators suited for education and learning are designed for IP communication. The author developed a simple CLI-based Ethernet simulator that can display contents of Ethernet packets to send or to receive in terminals and contents of MAC address tables in switches in “real time”, and used the simulator in a university class for learning computer networks. The simulator, which is in public domain, is written in Python and, thus, runs on Windows, Macintosh, Linux, and other operating systems. The use of this simulator was evaluated based on a report assignment. The evaluation result shows that the average score of the reports written by using the simulator was much better, although it is not statistically significant because the number of students is small. The simulator seems to be effective to learn behaviors of Ethernet-based networks.

ポスター展示写真

Kanada, Y., Communications and Network, Vol. 7, pp. 55-69, http://dx.doi.org/10.4236/cn.2015.71006
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Abstract – Network processors (NPs) are widely used for programmable and high-performance networks; however, the programs for NPs are less portable, the number of NP program developers is small, and the development cost is high. To solve these problems, this paper proposes an open, high-level, and portable programming language called “Phonepl”, which is independent from vendor-specific proprietary hardware and software but can be translated into an NP program with high perfor- mance especially in the memory use. A common NP hardware feature is that a whole packet is stored in DRAM, but the header is cached in SRAM. Phonepl has a hardware-independent abstrac- tion of this feature so that it allows programmers mostly unconscious of this hardware feature. To implement the abstraction, four representations of packet data type that cover all the packet op- erations (including substring, concatenation, input, and output) are introduced. Phonepl have been implemented on Octeon NPs used in plug-ins for a network-virtualization environment called the VNode Infrastructure, and several packet-handling programs were evaluated. As for the eval- uation result, the conversion throughput is close to the wire rate, i.e., 10 Gbps, and no packet loss (by cache miss) occurs when the packet size is 256 bytes or larger.

Kanada, Y., 第 13 回ネットワーク仮想化研究会, 2015-3.
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要約: In IP/Ethernet-based networks, redundant addresses, both IP and MAC addresses, are used. Problems caused by this redundancy can be solved by replacing IP/Ethernet by IP/null (IPON) protocol. It was implemented using VNodes.

研究テーマ紹介: ネットワーク仮想化