Design and evaluation of a high-performance switch architecture for free-space photonic switching systems is described. The switch is constructed of 22 switching elements and employs special multistage interconnection patterns. The connection setup algorithm and the control procedure at the switching elements are based on a "rerouting algorithm."" Performance analysis shows that the blocking probability of the switch is easily controlled by increasing the number of switching stages. Example implementations of this switch are shown in which birefringent plates, polarization controllers, etc. are used.

The rapidly increasing bandwidth requirements of IP traffic mean that networks based on optical technologies in conjunction with IP routing technologies will provide the backbone of the next generation Internet. One of the major issues is how to construct an optical-technology-based backbone network that offers the economical transport of large-scale IP/MPLS services while achieving reliable, robust network. The key to achieving this objective lies in multilayer coordination technologies using Multi-Layer Service Network [MLSN] Architecture, that we previously proposed [2]. One of the important aspects of MLSN architecture is ability to effectively use GMPLS network resources by IP/MPLS service networks. We propose extensions to previously proposed MLSN architecture. The proposed extensions to MLSN architecture are tailored to address "service virtualization and separation" of various service networks over GMPLS backbone. As a part of this extended MLSN architecture, we introduce novel concepts known as Logical Router (LR) and Virtual Router (VR) that would enable border router to be services domain router, so that it can connect multiple service networks such as L2VPN, L3VPN etc., over GMPLS backbone by offering service separation or virtualization. This service separation/isolation greatly enhances the reliability of next generation networks, as any failure on one service should be isolated from others. We evaluate our extended network architecture against requirements for the large scale network targeting at introducing such new technology to cope with vast traffic explosion and challenges in operation and service provision sophistication.

This paper proposes an advanced hybrid network architecture and a comprehensive network design of the next-generation science information network, called SINET3. Effectively combining layer-1 switches and IP/MPLS routers, the network provides layer-1 end-to-end circuit services as well as IP and Ethernet services and enables flexible resource allocation in response to service demands. The detailed network design focuses on the tangible achievement of providing a wide range of network services, such as multiple layer services, multiple virtual private network services, advanced qualities of service, and layer-1 bandwidth on demand services. It also covers high-availability capabilities and effective resource assignment in the hybrid network. The cost reduction effect of our network architecture is also shown in this paper.

This paper describes an architectural design and related services of a new Japanese academic backbone network, called SINET5, which will be launched in April 2016. The network will cover all 47 prefectures with 100-Gigabit Ethernet technology and connect each pair of prefectures with a minimized latency. This will enable users to leverage evolving cloud-computing powers as well as draw on a high-performance platform for data-intensive applications. The transmission layer will form a fully meshed, SDN-friendly, and reliable network. The services will evolve to be more dynamic and cloud-oriented in response to user demands. Cyber-security measures for the backbone network and tools for performance acceleration and visualization are also discussed.

IP-over-optical multilayer networks are capable of flexibly dealing with traffic increases and fluctuations because they support both high-speed transmission using lightpaths and scalable IP hop-by-hop transmission. This paper introduces an architecture for quality of service (QoS) control in such networks, based on the differentiated services (DiffServ) concept. The architecture supports both class-based queues and class-based lightpaths to efficiently handle multiple-QoS-class traffic. QoS schemes based on the proposed architecture are categorized into four types according to their traffic-differentiation and transmission mechanisms. Through simulation, the schemes are evaluated in terms of measures that largely determines network costs. Finally, the conditions under which each scheme is feasible are clarified in terms of the traffic volume and the cost of class-based queues for DiffServ.

This paper proposes a network design scheme for Virtual Private Network (VPN) services. Traditionally, network design to compute required amount of resource is based on static point-to-point resource demand. This scheme is effective for traditional private line services. However, since VPN services allow multi-site connectivity for customers, it may not be appropriate to design a network based on static point-to-point resource demand. In particular, this scheme is not effective when the traffic pattern changes over time. Therefore, network design for VPN services introduces a new challenge in order to comply with traffic flexibility. There are conventional studies tackling this issue. In those studies, by defining a resource demand model considering flexibility, and designing the network based on this model, amount of resource required can be computed. However, there are some deficiencies in those studies. This paper proposes a new network design scheme, consisting of two components. The first one is a new resource demand model, created by extending conventional resource demand models, that can specify resource demand more precisely. The second one is a new network design algorithm for this resource demand model. Simulations are conducted to evaluate the performance of the proposed network design scheme, and the results show significant performance improvement against conventional schemes. In addition, deployment considerations of the proposed scheme are analyzed.

This paper proposes resource management in Layer 1 Virtual Private Networks (VPNs). We have been proposing Layer 1 VPNs that provide layer 1 services to multiple customers over the single optical network with per VPN control and management capabilities. We have proposed two resource management models for Layer 1 VPNs, which constitute different class of services. One is the shared model, where resources are shared among VPNs. The other is the dedicated model, where resources are explicitly pre-assigned to each VPN. In this paper, after introducing an overview of Layer 1 VPNs, we evaluate several path computation algorithms for these two models focusing on the multi layer network scenario. In the shared model, there are several existing studies for non-VPN cases, but considerations for VPN cases are not investigated. This paper evaluates algorithms originally proposed for non-VPN cases for use in VPN cases. Simulation results show that the path computation algorithm that works as saving layer 1 resources achieves better resource sharing effect. In the dedicated model, the problem is identical to non-VPN cases. There is one conventional algorithm, but amount of available resources is not well considered. We propose a novel path computation algorithm. Simulation results show effectiveness of our proposed algorithm against the conventional algorithm. Furthermore, resource usage efficiency of two resource management models is compared. We analyze and propose applicability of resource management models.

This paper describes the architectural design, services, and operation and monitoring functions of Science Information NETwork 6 (SINET6), a 400-Gigabit Ethernet-based academic backbone network launched on a nationwide scale in April 2022. In response to the requirements from universities and research institutions, SINET upgraded its world-class network speed, improved its accessibility, enhanced services and security, incorporated 5G mobile functions, and strengthened international connectivity. With fully-meshed connectivity and fast rerouting, it attains nationwide high performance and high reliability. The evaluation results of network performance are also reported.

Communication networks are now an essential infrastructure of society. Many services are constructed across multiple network domains. Therefore, the reliability of multi-domain networks should be evaluated to assess the sustainability of our society, but there is no known method for evaluating it. One reason is the high computation complexity; i.e., network reliability evaluation is known to be #P-complete, which has prevented the reliability evaluation of multi-domain networks. The other reason is intra-domain privacy; i.e., network providers never disclose the internal data required for reliability evaluation. This paper proposes a novel method that computes the lower and upper bounds of reliability in a distributed manner without requiring privacy disclosure. Our method is solidly based on graph theory, and is supported by a simple protocol that secures intra-domain privacy. Experiments on real datasets show that our method can successfully compute the reliability for 14-domain networks in one second. The reliability is bounded with reasonable errors; e.g., bound gaps are less than 0.1% for reliable networks.

Cost-effective cloud storage services are attracting users with their convenience, but there is a trade-off between service availability and usage cost. We develop two cloud provider selection models for cloud storage services to minimize the total cost of usage. The models select multiple cloud providers to meet the user requirements while considering unavailability. The first model, called a user-copy (UC) model, allows the selection of multiple cloud providers, where the user copies its data to multiple providers. In addition to the user copy function of the UC model, the second model, which is called a user and cloud-provider copy (UCC) model, allows cloud providers to make copies of the data to deliver them to other cloud providers. The cloud service is available if at least one cloud provider is available. We formulate both models as integer linear programming (ILP) problems. Our performance evaluation observes that both models reduce the total cost of usage, compared to the single cloud provider selection approach. As the cost of bandwidth usage between a user and a cloud provider increases, the UCC model becomes more beneficial than the UC model. We implement the prototype for cloud storage services, and demonstrate our models via Science Information Network 5.

This paper describes the design and evaluation of a high-performance multicast ATM switch and its feasibility study, including its 40 Gbit/s LSI packaging. The multicast switch is constructed using a serial combination of rerouting networks and employs an adapted Boolean interval-splitting scheme for a generalized self-routing algorithm. Analysis and computer simulation results show that the cell loss probability is easily controlled by increasing the number of switching stages. It is shown that the switch configuration can be transformed into other patterns to be built from banyan-based subnetworks of arbitrary size for LSI packaging. It is also shown that an LSI chip integrating an 88 banyan-based subnetwork using 0. 25-µm CMOS/SIMOX technology can attain a 40-Gbit/s switching capability.

The growth in the volume of Internet traffic and the increasing variety of Internet applications require Internet backbone networks to be scalable and provided sophisticated quality of service (QoS) capabilities. Internet backbone routers have evolved to achieve sub-Tbps switching capacity in a single unit, but their switch architectures have limited scalability, causing QoS to degrade as the switches get bigger. Hence, we propose a large-scale IP and lambda integrated router architecture with scalable switches. We first describe the system architecture of our proposed backbone router and clarify the requirements for its switching capabilities to meet near-future demands. The new switch architecture, using crossbar-based switching fabrics and optical interconnection devices, meets the requirements for a backbone router to scale up to 82 Tbps and enable light path switching as well as packet switching. The routing tag and its usage algorithm in the switch, and packaging issues, including the quantity of hardware required for expansion, are also discussed.

This paper proposes a Generalized Traffic Engineering Protocol (GTEP). GTEP is a protocol that permits communication between a Path Computation Element (PCE) and a Generalized Multi-Protocol Label Switching (GMPLS) controller (CNTL). The latter is hosted by each GMPLS node; it handles GMPLS and MPLS protocols such as routing and signaling protocols as well as controlling the GMPLS node host. The PCE provides multi-layer traffic engineering; it calculates Label Switched Path (LSP) routes and judges whether a new lower-layer LSP should be established. GTEP functions are implemented in both the PCE and GMPLS router. We demonstrate a multi-layer traffic engineering experiment conducted with GTEP.

Design and evaluation of a high-performance switch architecture for free-space photonic switching systems is described. The switch is constructed of 22 switching elements and employs special multistage interconnection patterns. The connection setup algorithm and the control procedure at the switching elements are based on a "rerouting algorithm." Performance analysis shows that the blocking probability of the switch is easily controlled by increasing the number of switching stages. Example implementations of this switch are shown in which birefringent plates, polarization controllers, etc. are used.

The bandwidth explosion ushered in by the popularity of the Internet has spurred the recent acceleration in the development and deployment of equipment supporting packet based broadband services. This coupled with the widespread deployment of WDM based Optical Transport Systems in the core network to satisfy the corresponding increase in capacity demand, has led network planners for tighter coordination between IP and Optical layers to increase reliability, robustness of next generation backbone network. In this paper, we propose a solution known as border model, which is tailored to address deployment concerns associated with GMPLS technology in existing networks. We extend our proposal to include, "Border model based Multi-layer service network architecture," to provide coordinated multi-layer IP and Optical services, for different network design scenarios. Resource Control is an important aspect of multi-layer service networks. This paper examines next generation requirements for resource control, defines resource control architecture and presents some evaluation results for multi-layer recovery techniques in the context of Multi-layer service network based on border model.