Naohide Nagatsu

Optical path cross-connect system scale evaluation using path accommodation design for restricted wavelength multiplexing

The optical path (OP) technology, which employs both wavelength-division multiplexing and wavelength routing, will be the key to enhanced network integrity and an ubiquitous broadband integrated services digital network (B-ISDN) in the future. To construct the OP network, path accommodation design that can solve simultaneously the problems of path routing and wavelength assignment must be established. Since optical wavelengths are scarce resources, even with state-of-the-art technologies, the available number of wavelengths that can be multiplexed into a fiber is restricted to a relatively small number. This entails space division multiplexing with multiple fibers in the link in order to accommodate the large number of paths within a link. This paper proposes novel OP accommodation design algorithms that can heuristically establish wavelength paths (WPs) or virtual wavelength paths (VWPs) in the network, where each link is composed of multiple fibers. These algorithms minimize the average number of fibers (in other words, cross-connect ports) handled at the WP/VWP cross-connect nodes and enable us to obtain the required OP cross-connect (OPXC) system scale at each node in WP/VWP networks. Algorithms that consider failure restoration are also proposed. Some WP/VWP accommodation designs over a polygrid network are simulated using the proposed algorithms. The difference between the WP and VWP schemes in terms of the required OPXC system scale with and without considering failure restoration is quantitatively evaluated for the first time.

G-lambda: coordination of a grid scheduler and lambda path service over GMPLS

A vertical coordination between computing resource scheduler and network resource scheduler for Grid-based applications is described. The network resource management system virtualizes and schedules network resources to inter-work with Grid resource scheduler through Web-services interface.

Architectural analysis of multiple fiber ring networks employing optical paths

Analyzes the performance of various types of multiple fiber ring networks employing optical paths (OPs). The multiple fiber ring network architecture is suitable for achieving failure resilient networks that have extremely large bandwidth but are still upgradable against future increases in traffic. This architecture will overcome the limitation of conventional WDM rings in terms of network expansion capabilities, the number of nodes within the ring, and the number of OPs accommodated in the network. The generic node architecture suitable for multiple fiber ring networks is presented and functionality requirements are identified. The OP accommodation design algorithms that minimize the required node system scale are proposed. Based on the generic node architecture and proposed OP accommodation design algorithms, we evaluated the performance of several types of multiple fiber rings in terms of the required node system scale for rings under various conditions. The effect of the ring architecture (uni-/bidirectional rings), optical path schemes (wavelength path/virtual wavelength path), and different node connectivity patterns are demonstrated for the first time. The obtained results elucidate the criteria for selecting the most suitable multiple fiber ring architecture.

Network design and cost optimization for label switched multilayer photonic IP networks

Dealing with the explosive increase in the amount of Internet traffic requires high-speed and huge capacity Internet protocol (IP) backbone networks. Existing IP backbone networks are constructed using point-to-point wavelength-division-multiplexing (WDM) transmission systems, where all the wavelengths are terminated link-by-link, so that rather expensive optical/electrical conversions are necessary at every node. In these systems, since every IP packet is routed at each intermediate node based on the header information, a header processing bottleneck will occur when the node input traffic exceeds several hundreds of gigabits per second. In order to mitigate these problems, an optical cross-connect (OXC) function that employs wavelength routing of the optical paths (OPs) will provide an effective solution. This paper proposes a network design method where electrical and photonic multiprotocol label switching (MPLS) technologies are used; the network is referred to as a photonic IP network. We first propose new algorithms that minimize the network cost in a multilayered network comprising electrical label switched paths (LSPs) and optical LSPs (optical paths that are controlled using the MPLS mechanism). The particular point of the proposed algorithms is that they include different cost minimization scenarios appropriate for the different OLSP provisioning conditions that are chosen as the first step in the design stage. The effectiveness of the proposed algorithms and the benefits of the OLSPs are quantitatively evaluated through various simulations.

The first functional demonstration of optical virtual concatenation as a technique for achieving terabit networking

The optical virtual concatenation (OVC) function of The Terabit LAN was demonstrated for the first time at the iGrid 2005 workshop in San Diego, California. The TERAbit-LAN establishes a lambda group path (LGP) for an application where the number of lambdas/L2 connections in a LGP can be specified by the application. Each LGP is logically treated as one end-to-end optical path, so during parallel transport, the LGP channels have no relative latency deviation. However, optical path diversity (e.g. restoration) can cause LGP relative latency deviations and negatively affect quality of service. OVC hardware developed by NTT compensates for relative latency deviations to achieve a virtual bulk transport for the Electronic Visualization Laboratorys (EVL) Scalable Adaptive Graphics Environment application.

Managing and controlling GMPLS network resources for grid applications

Inter-working between GMPLS network and grid computing application through Web-services interface is demonstrated for the first time. Lambda LSP-based network resource virtualization and scheduling techniques successfully achieves nation-wide grid computing environment with advance reservation operation.

Optical path accommodation design considering failure restoration with minimum cross-connect system scale

This paper proposes optical path accommodation design algorithms for both the wavelength path (WP) and virtual wavelength path (VWP) schemes with or without failure restoration. The optical path (OP) employs WDM/FDM (wavelength/frequency division multiplexing) and wavelength routing in the path layer of the transport network. The proposed algorithms adopt some heuristic approaches to the algorithmic complexity caused by the NP-completeness of the wavelength assignment problem. The objective function is taken as minimizing the average total number optical path cross-connect (OPXC) ports, in other words, OPXC system scale. Utilizing the developed algorithms, extensive simulations quantitatively evaluate the OPXC system scale requirements of a large scale network whose physical topology and path demand distribution pattern are arbitrary. The simulations reveal the basic difference between the WP and VWP schemes.

The First Application-driven Lambda-on-Demand Field Trial over a US Nationwide Network

The Lambda-on-demand functionality with link aggregation to accommodate the dynamic bandwidth demands of an ultra-high-resolution visualization application was realized in over a US nationwide photonic network for the first time.

Stable IP-Routing Link Restoration: GUNI Restoration for Data Link Failure Between Routers in a Nationwide Photonic Network

A GMPLS (Generalized Multi-Protocol Label Switching)-based link restoration scheme with IP-routing stability for data link failure between routers through a PXC (Photonic Cross-Connect) network was proposed and successfully demonstrated in a US nationwide photonic network for the first time.

Failure restoration in photonic transport networks using optical paths

Summary form only given. Optical path technologies such as WP (wavelength path) and VWP (virtual wavelength path) will play a key role in the transport network evolution. They enhance not only transmission capacity but also cross-connect node throughput cost-effectively by capitalizing on the wavelength routing scheme. A new cross-connect system architecture has been proposed that has various advantages; WP to VWP up-gradability, modular growth capability, and low optical loss and cross talk. The architecture exploits PLCs (planer lightwave circuits).