SINET5 is a new 100-Gbps-based academic backbone network, which started full-scale operations in April 2016. It uses multi-protocol label switching-transport profile (MPLS-TP) systems and reconfigurable optical add-drop multiplexers (ROADMs) to create a nationwide network and has more than 50 backbone IP routers to provide a wide range of services, such as several virtual private network (VPN) services. It provides end-to-end data communications up to 100 Gbps throughput, minimized-latency, and software-defined networking (SDN)-friendly functions to researchers in every Japanese prefecture. SINET5 is also a platform for dynamic inter-cloud connections and network functions visualization (NFV) services. This paper brief review of the network architecture, and describes new featured services, SDN-oriented layer-2 on-demand VPN services, and NFV functions. Field test results for SINET5 performance are also reported.

In recent years, as mobile devices increase, the demands for measuring the available bandwidth in a wireless network increase more and more to provide high quality network services. The available bandwidth is one of the most important parameters to determine the sending rate in WAN optimization. Pathload [2] is a technique to measure the available bandwidth by detecting the point where the receiving rate becomes lower than the sending rate of test packets. However, Pathload misdetects this point in mobile networks with packet losses caused by fading, interference, and so on. So, we propose a method to measure the available bandwidth by using correlation coefficients between the sending rate and packet loss rate, and then evaluate the accuracy of the proposed method.

Recently, many commercial cloud-computing services have rapidly evolved to process and back up large volumes of data. With wireless broadband networks also gaining popularity, users increasingly access cloud services using mobile devices and wearable devices for interactive communication, such as remote desktops and augmented reality (AR) applications. In many cases, interactive applications use the TCP protocol between a server and a mobile device. However, end-to-end TCP sessions are easily influenced by packet losses in wireless networks and long delays on international lines, which may degrade communication quality. To cope with these problems, we propose a dynamic TCP communication method that improves the response for interactive communication by dynamically changing congestion control algorithms in accordance with changes in network quality and application characteristics. In this paper, we implement the proposed method on the NS-3 network simulator and evaluate it by using the GE (Gilbert-Eliott) channel model, assuming that the method is applied to a Wi-Fi network. We find that our method improves response time for interactive communication with a remote desktop to the level where users will not feel uncomfortable.

Due to a mismatch between downloading and caching content, the network may not gain significant benefit from the sophisticated in-network caching of information-centric networking (ICN) architectures by using a basic caching mechanism. This paper aims to seek an effective caching decision policy to improve the content dissemination in ICN. We propose PopCache-a caching decision policy with respect to the content popularity-that allows an individual ICN router to cache content more or less in accordance with the popularity characteristic of the content. We propose an analytical model to evaluate the performance of different caching decision policies in terms of the server-hit rate and expected round-trip time. The analysis confirmed by simulation results shows that PopCache yields the lowest expected round-trip time compared with three benchmark caching decision policies, i.e., the always, fixed probability and path-capacity-based probability, and PopCache provides the server-hit rate comparable to the lowest ones.

This paper describes the implementation and evaluation of layer-1 bandwidth-on-demand (BoD) capabilities in the Japanese academic backbone network, called SINET3. The network has a nationwide GMPLS-based layer-1 platform and provides reservation-based and signaling-based BoD services. The overall architecture for providing BoD services including its capabilities, user interface, path calculation, and interface to drive the layer-1 platform are described. Actual examples of BoD services and evaluations of the path setup/release time in the network are also presented.

This paper describes the network design and configurations of the new Japanese academic infrastructure, called SINET3, which provides a rich variety of network services to more than 700 universities and research institutions. Since the start of full-scale operations in June 2007, the network has expanded its services to include multi-layer transfer services (IP, Ethernet, and layer-1), enriched virtual private network services (L3VPN, L2VPN, VPLS, and L1VPN), enhanced QoS services (packet-based and circuit-based), and brand-new layer-1 bandwidth-on-demand (BoD) services. This paper explains how the network provides these various network services on a single network platform by effectively configuring leading-edge networking components, such as high-performance IP routers, layer- 1 switches, and a BoD server. Evaluations of the network design and configurations confirmed that the networking functions were effectively coordinated. The procedures and techniques related to the configuration validation that covered all phases of the network design and construction are also presented.

Traffic volume anomalies refer to apparent abrupt changes in time series of traffic volume, which can be propagate through the network. Detecting and tracing anomalies is a critical and difficult task for network operators. In this paper, we first propose a traffic decomposition method, which decomposes the traffic into three components: trend component, autoregressive (AR) component, and noise component. A traffic volume anomaly is detected when the AR component is out of prediction band for multiple links simultaneously. Then, the anomaly is traced using the projection of the detection result matrices for the observed links which are selected by a shortest-path-first algorithm. Finally we validate our detection and tracing method by using traffic data of the third-generation Science Information Network (SINET3) and show the detected and traced results.

This paper describes brand-new layer-1 bandwidth on demand (BoD) services implemented in the new Japanese academic backbone network, called SINET3. SINET3 is an advanced converged network that provides multi-layer transfer, enriched VPN, enhanced QoS, and layer-1 BoD services. The layer-1 BoD services are dynamic layer-1 resource allocation services directly triggered by users and artfully achieved on the multi-service platform by using a layer-1 BoD server. This paper first explains how the network accommodates a wide variety of network services by effectively combining leading-edge technologies. The paper next describes the overall mechanism for the dynamic layer-1 path setup on the multi-service platform and details the functions of the BoD server in many aspects. The designs focus on the tangible achievement of these services over a nationwide network composed of 75 layer-1 switches and 12 IP/MPLS routers.

Nowadays various kinds of anomalies are prohibiting the widely used Internet from offering normal services. Within them a novel anomaly is caused by bandwidth attacks. To defense these threats many detecting schemes are essentially based on unidirectional checking of traffic changes. When legitimately abrupt changes appear, they might result in false alarms. In this paper we consider the problem from the bidirectional-traffic view and analyze the traffic characteristics by checking the input/output traffic characteristics of the protected network node. We have analyzed the relationship between input and output traffic volume pairs in the simulation traffic and studied them both under normal and abnormal cases. Based on these analyses, we've proposed a heuristic DDoS flooding attack detection method and showed a verifying simulation as well.

Optical burst switching (OBS) is a promising switching technology for the next optical transport network. In this paper, we analyze the assembled traffic of the science information network (SINET) by using the fractional Brownian motion (FBM) model. The analytical results show that the general timer-based assembly scheme can not avoid increasing the burstiness (variance in short timescales), which will deteriorate the network performance. Therefore, a novel burst assembly method with traffic shaping function named advanced timer- based is introduced to reduce the burstiness of assembled traffic, in which the traffic rate is smoothed by restricting the burst length to a threshold when bursts are sent out periodically. The simulation results show that the advanced timer-based assembly algorithm is better than existing assembly algorithms in terms of burst loss ratio.

The authors describe an ATM traffic control method to avoid both long-term and short-term congestion. Call admission control and policing based on user-specified traffic parameters have mainly been studied as ways to avoid long-term congestion. However, these control methods are not practical since it is difficult for users to specify accurate values of traffic parameters that include the effects of cell collision controllers and multiplexers in the customer premises network. In order to solve the problem, they propose an intelligent call admission control method. This method consists of a function to determine user's traffic parameters by monitoring the cell traffic flow of each service and a function to statistically predict long-term congestion by using Gaussian and Poisson distributions. They show that congestion can be predicted by deriving the peak, average, and variation. They also describe how to derive traffic parameters and determine their values. To avoid short-term congestion, we propose reactive control, which drops cells with lower cell loss priority when congestion occurs, and we show the buffer construction and buffer control algorithm used to achieve this. Computer simulations prove that their control strategy is effective for cell toss sensitive services such as VBR (variable bit rate) video service.>

To improve the ratio of successful calls, a new switching system permitting callers to store messages when the called party is busy or does not answer can be constructed by adding a message storing function to the conventional circuit switching system. The mutual traffic influences exerted by this combination of circuit and message switching systems have not yet been clarified. This paper considers a two-stage loss system traffic model consisting of a circuit switching system that has a message switching system connected to it. The traffic characteristics of this model are analyzed using the nonindependent state transition probability, which depends upon the interacting states of the circuit and message switching system. A method of solving the state equations by determining the state transition probabilities of the message switching system from the state probabilities of the circuit switching system is proposed. Using this method, the mutual traffic influence of the circuit and message switching systems is evaluated.