Published papers

In the new generation network, information-centric networking (ICN) is one of the most promising technologies for communication systems which are suitable for the content data provisioning and delivery from/to users. To create a new ICN on the JGN-X network virtualization platform, developing new networking technologies such as virtual network resources control from users, in-network processing for content data creation, and energy efficient routing on the virtual network, were challenged.

The elastic lambda aggregation network (EλAN) has been presented as an access/aggregation integrated network that can accommodate multiple network services. In the EλAN, optical line terminals (OLTs) become programmable and configure logical OLTs (L-OLTs) to support network services that have different protocols and quality of service requirements. To achieve the flexible utilization of network resources and improve energy efficiency, L-OLTs are migrated between programmable OLTs like virtual machines. In this paper, an integer linear programming (ILP) model of the L-OLT placement optimization problem with optical distribution network constraints is presented. Based on this ILP model, the communication suspension time that occurs with L-OLT migration is investigated. We discuss the modification of the L-OLT migration sequence to reduce the communication suspension time. The impact of the modification on the energy saving effect of L-OLT placement optimization is evaluated in this paper.

An energy-saving strategy for application-centric networks is proposed. A new architecture for energy-efficient Ethernet that meets the quality of service requirements for different classes of service is studied.

Active Optical Network (ActiON) using a conventional slot allocation method in Plumbum Lanthanum Zirconate Titanate (PLZT) optical switches was proposed. The conventional slot allocation method shortens the switching idle time, which is a product of the switching guard time and the number of switching times. However, the transmission waiting time could exceed a user’s allowable delay. This paper proposes a delay-sensitive slot allocation method, which minimizes the switching idle time while considering the user’s allowable delay. Numerical results show that the proposed method reduces the number of switching times by up to 88 percent when compared to the conventional method.

Information-centric networking (ICN) as an alternative has been researched for future Internet architecture. In this paper, a novel network architecture called Energy Efficient and Enhanced-type Data-centric Network (E3-DCN) is proposed for ICN. E3-DCN not only realizes ICN but also has the ability of data generation by organizing and combining relevant resource such as original data and kinds of processing services. In addition, in order to improve energy efficiency of data transmission, E3-DCN chooses optimal transmission path to transmit data based on packet switching and optical switching. Moreover, based on current traffic situation, E3-DCN reconfigures network topology such as unused nodes and links to operate in sleep mode for energy saving dynamically. And meanwhile, data caching strategies are applied into E3-DCN for data distribution based on the distribution of users. Data caching shortens transmission distance, so data transmission energy, latency and network load is decreased. Based on these approaches, E3-DCN achieves an energy efficient network.

The tenth International Conference on IP + Optical Network (iPOP) was held this year. This event consisted of an international conference and exhibition on next-generation networks combining optical and IP technology, and as the largest conference of its kind it has important influence over dejure and de facto standards. This report describes the features and purpose of this event.

1960年にT.H.Maimanがヒューズ・リサーチ・ラボラトリで初めてレ-ザ光の発振に成功してから50年を迎えた.電子情報通信学会東京支部では,記念すべきこの年に,レ-ザの発展に多大な貢献をされた霜田光一,末松安晴両博士の講演会を7月1日に開催した.レ-ザ研究の経緯や発見・発明のエピソード,開発の苦労,その後の応用について,当時を知る両氏からしか聞くことのできない貴重な話を伺った.講演会の後,両氏の厚意により, 50年前の古い資料を拝見するアーカイブズ展示会を実施した. Maiman,Javan, Lambら,メ-ザ・レ-ザのれい明期の論文や手書き原稿,当時の写真,レ-ザ発明当時の製造機器,世界をリードしてきた日本国内各社のレ-ザ製品,関連するノーベル賞受賞者と講師の交流の記録などに多くの参加者が見入った.今日,情報,通信,映像などのICT産業のみならず, 医療,加工,分析などあらゆる分野においてレ-ザが果たしている役割の大きさは計り知れない.講演会,展示会とも,レ-ザ発明の歴史的偉業とその後の発展の歴史のみならず,日本の進むべき技術立国のビジョンに対して勇気と活力を与えられるものであった.講演会当日は, 200名を超える聴衆が会場を埋め尽くしたが,このような貴重な講演は,聴講者だけでなく,その一端だけでも広く会員に紹介すべきとの意見を多数頂だいしたため,本誌に寄稿するものである.

加入者毎に光スイッチを入れて加入者数の拡大と長遠化を図った. 10nsでスイッチングするPLZTを用いて日立製作所と共同でOLT/ONUを試作し, 実験を行なった.

In an active optical access network with high-speed optical switches, a precise ranging method adopting dynamic packet (frame) is proposed. In the experiment using our developed prototypes of OLT, ONUs and a switch emulator, a dynamic packet based ranging method between OLT and ONUs was successfully executed.

This paper proposes high-energy efficient future-Internet architecture. All traffic is aggregated to a solitary universal cloud router through an optical aggregation network. Evaluation shows power consumption can be reduced to 1/1000 compare to present Internet.

Green ITとよばれ近年, 地球環境に配慮した技術開発が重視されつつある. 情報ネットワークの分野においてもネットワークの広帯域化とサービスの質の向上による増え続ける需要をさばくためのネットワークリソースは急増し, それによる看過できない電力消費の伸びが指摘され始めるなどており, ネットワークの省電力化は今後重視すべき課題である. 装置やデバイスのみではなく, 運用方法やアーキテクチャを組み合わせた検討が必要である. 本提案は, いままであまりアプローチされていなかった, 通信ネットワークの消費電力を通信品質を保証しながら最適に制御する方法を, すべての組み合わせを計算する方法を研究した. いままでは計算時間が膨大過ぎて現実的ではないと思われていた集合被覆問題に帰着させ, リコンフィギャラブルプロセッサデバイスを用いて高速に解き, さまざまなネットワークリソースを, もっとも省電力で使用する構成を動的に求めることを可能にするものである. 具体的にはネットワークリンクを必要最小数のみパワーオンし, またルートも必要最少とするような省電力ルータの制御を行うことができる計算エンジンを提案する. また, エンジンによって計算した結果を実ネットワークに反映させ, リンクをon/offするプロトコルをGMPLSを拡張して実現し, また, プロトタイプシステムで実験的に確認した.

A new optical access network architecture called called Active Optical Network (ActiON) is proposed which uses a newly-developed 10 nsec PLZT((Pb, La)(Zr, Ti)O3) high-speed optical switch. ActiON can handle four times the number of subscribers(128) that GEPON can handle as well as doubling the transmission distance(to 40 km). Moreover, users can enjoy secure communication in ActiON because it is a switch-based system. However, ActiON has to overcome a Discovery-Ranging process issue because an optical switch cannot broadcast signals. In this paper, the architecture of ActiON and a novel Discovery-Ranging process technique is proposed. The proposed access system architecture and high-speed PLZT switch will be able to be applied to next generation broadband access systems. Keywords

In an active optical access network with high-speed optical switches, a precise ranging method adopting dynamic packet (frame) is proposed. In the experiment using our developed prototypes of OLT, ONUs and a switch emulator, a dynamic packet based ranging method between OLT and ONUs was successfully executed.

The first global interoperability experiment of GMPLS controlled Ethernet with VLAN tag swapping between two different implementations is successfully demonstrated. High definition video streaming is realized through a newly established Layer 2 Label Switched Path (L2-LSP). The results of this experiment can be applied to designing reliable Layer 2 networks.

How to minimize the number of mirroring resources under a QoS constraint (resource minimization problem) is an important issue in content delivery networks. This paper proposes a novel approach that takes advantage of the parallelism of dynamically reconfigurable processors (DRPs) to solve the resource minimization problem, which is NP-hard. Our proposal obtains the optimal solution by running an exhaustive search algorithm suitable for DRP. Greedy algorithms, which have been widely studied for tackling the resource minimization problem, cannot always obtain the optimal solution. The proposed method is implemented on an actual DRP and in experiments reduces the execution time by a factor of 40 compared to the conventional exhaustive search algorithm on a Pentium 4 (2.8 GHz).

A multi-domain GMPLS layer-2 switch capable network with VLAN tag swapping is demonstrated for the first time. In this demonstration, we verify three new features; establishing path with designating VLAN IDs, swapping VLAN ID on prototype switch, and management of VLAN IDs per domain. Using those three features, carrier-class multi-domain Ethernet backbone networks which supports independently resource management per domain can be established.

Frame loss of the optical layer protection switching using Plum bum Lanthanum Zirconium Titanium (PLZT) optical switch is evaluated. Experimental results show that typically 62 us guard time is required for commercially available non-burst mode 10 Gigabit Ethernet modules.