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We propose an extension of distcloud-fs for achieving a global distributed POSIX file system in intercloud environment. The file system works in intercloud environment, that is, on the top of multiple independent cloud services. The important capability of the intercloud extension is that there is no need for users to take care of infrastructure layer, while the file system stores data into multiple cloud services, transparently and automatically. As the result, cloud users may have diversity about vendors and locations for data platform, as discussed in various intercloud research projects. In this paper, we describe the architecture of the distcloud-fs and its intercloud extension. We also describe design and implementation of the prototype and discuss some typical use cases of the file system with practical demonstrations.

This paper gives a brief report on a new 100-Gbps academic backbone network, called SINET5, which started full-scale operations in April 2016. SINET5 has more than 50 backbone routers and forms a fully meshed topology by using MPLS-TP systems to provide researchers in every Japanese prefecture with 100-Gbps access, minimized-latency, and SDN-friendly environments. SINET5 gives a multi-layer, dynamically configurable, and performance-tunable platform for a wide range of network applications including inter-cloud services. The multi-layer network design, new functions including SDN and cloud-oriented functions, and field test results on performance and reliability are reported.

By making the best use of limited bandwidth, quality of service (QoS) provisioning over internet is essential for satisfying various types of internet-application requirements. The traffic classification and scheduling are the key functions to provide various kinds of class of service (CoS) under an overload condition. This paper investigates QoS performance in a network equipment testbed when implementing these main functions. We examine the major CoS functions provided by the Juniper T320 router, and measure their performance. In addition to fundamental analysis of the QoS behavior, we show the impact of QoS operations on a parallel system distributed in multi-domain networks as a practical case study of grid environments.

WAN optimization becomes a well-known technique to improve transmission rate in file transfer applications and interactive applications served in international cloud services. WAN optimization technique can improve transmission speed by using high performance protocols instead of TCP between both ends of wide area network, which has a large round trip time and a high packet loss rate. There are some kinds of high performance protocols, and their effectiveness in improving communication are different from each other based on the characteristics of the networks and applications. When WAN optimization technique is only used at both ends of a heterogeneous network containing networks such as wireless networks, international leased lines, etc. (e.g., access from a mobile device to a foreign cloud data center), improvement in communication is limited because only one high performance protocol is being applied. Therefore, we propose “distributed WAN optimization technique” that dynamically changes high performance protocols and sections to adapt those protocols based on network characteristics and applications.

Commercial cloud services are growing rapidly, and system architecture that can process large volumes of large-scale data for mobile devices and sensing devices is expected to emerge in the future. Mobile devices will serve as both client terminals and virtual machines in such architecture. However, end-to-end TCP sessions are affected by frequent changes in wireless link quality and movement of virtual machines in the cloud data center. In this paper, we propose a method to improve communication performance by dynamically reselecting and retuning congestion control algorithms and parameters according to changes in link quality and attributes of applications.

This paper describes flexible resource allocation and provision methods for bandwidth on demand and networks on demand in the new Japanese academic backbone network, called SINET3. SINET3 has provided a wide variety of network services such as IPv4/IPv6 dual stack, L3VPN, L2VPN/VPLS, and L1VPN services for the research and education community and started layer-1 bandwidth-on-demand services in February 2008. In SINET3 each service network is implemented as a logical service network on a single network platform by effectively combining latest technologies including logical router capabilities of IP/MPLS routers and flexible resource allocation capabilities of layer-1 switches. SINET3 can also easily create logically separated experimental network environments for new research projects. Evaluation results on some capabilities in experimental environments and demonstration results on bandwidth-on-demand capabilities in the real network are also shown in this paper.

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.

Several micromobility protocols have been proposed to improve the handover performance of Mobile IP. We present a novel seamless micromobility scheme based on explicit multicast (Xcast). In our proposal, the mobile traffic of its forward direction is sent to the potential access routers of a mobile node (MN) by including IP addresses of the access routers explicitly in the IP headers. As for IEEE 802.11b Wireless LAN, because it is difficult to know the potential ARs of a mobile node, a new trigger, called as the Candidate AR Trigger (CAT), is introduced to get this information from lower layer than IP. The CAT threshold, as certain threshold of MN's received signal level, is defined to invoke CAT. The determination method of the CAT threshold is depicted by an example in simulation. Finally, by using a combination of performance evaluation and simulation, we argue that our architecture is capable of providing packet lossless handover with latency similar to that of link level handover delay.