This article presents the architecture and operations of ARENA-PAC, a globally geo-distributed high-bandwidth research and education network. We highlight the experiments on ARENA-PAC and present a site-dedicated prefix design that keeps each PoP independently reachable, and describe an anycast-based resilient service and measurement research as two applications built on this design.

Improvements in fabrication devices such as 3D printers are becoming possible for personal fabrication to freely fabricate any products. To clarify who is liable for the product, the fabricator should keep the fabrication history in an immutable and sustainably accessible manner. In this paper, we propose a new scheme, "Fabchain," that can record the fabrication history in such a manner. By utilizing a scheme that employs a blockchain as an auditable communication channel, Fabchain manages print jobs for the fabricator’s 3D printer over the blockchain, while maintaining a history of a print job. We implemented Fabchain on Ethereum and evaluated the performance for recording a print job. Our results demonstrate that Fabchain can complete communication of a print job sequence in less than 1 minute on the Ethereum test network. We conclude that Fabchain can manage a print job in a reasonable duration for 3D printing, while satisfying the requirements for immutability and sustainability.

Applications requiring strict access control, such as medical record query, often require auditing of the query. The current typical design relies on server side logging. However, logging on server-side do not provide strict means of auditing, since the server can be tampered with attackers, and also anybody who has permission to write can modify the log. We propose a scheme using blockchain technology, as a request-response channel for a client-server system, to record both client request and server reply in an audi-table manner. We have implemented a proof-of-concept system on top of a publicly available blockchain testbed. By using a blockchain as a client-server request-response channel, the request-response sequence can be verified by anybody who has access to the blockchain, providing a way to implement audit log for strictly controlled resources.

We propose the Floating Ground Architecture (FGA) for network mobility and ad hoc network convergence. Various factors, including excessive dependence on intelligence in the fixed network, result in the Internet having a de facto logical boundary one hop from the fixed network. To reduce these dependencies, FGA introduces a new logical layer, called Floating Ground, between the fixed network infrastructure and the mobile network, aiming to bridge these different types of network systems. Thanks to the effect of this buffer layer, the architecture: 1) optimizes routes in a deeply nested mobile router arrangement, 2) simplifies mobility event handling under frequent movement of the nodes, and 3) transparently introduces additional functionality with no additional intelligence on the infrastructure side. Through evaluation of our proposed architecture using an actual software implementation running via Direct Code Execution simulation, optimized routes are confirmed with three possible mobility scenarios, demonstrating the handoff duration is dramatically reduced in the short-distance movement scenario, which happens in 78.4%, at maximum, of the handoff events under actual taxi cabs movement in real world. Qualitative analysis of FGA shows it minimizes modification of the network components and existing standardized protocols, and is therefore more suitable for self-organized, distributed network extension than competitive approaches.

Radio frequency identification (RFID) is an automatic identification technology which identifies physical objects individually according to their unique identifiers (ID) recorded in each RFID tag. Many business processes require the integrity verification of a group of objects in addition to individual object identification. This paper proposes “group coding” of RFID tags with which we can verify the integrity of groups of objects by writing parity check data to the memory of RFID tags. It was revealed by simulations and experiments that we could determine the number of missing RFID tags up to 10 with accuracy over 99% when we write 96 bits of the checksum data to 20 RFID tags. The whole duration of group decoding measured in the experiment was approximately 2 to 3 s. The time to compute group encoding and decoding was in the order of several milliseconds and thus negligible. The RFID inventory accounts for the majority of the duration. Note to Practitioners-Current RFID features fast identification of many physical objects. However, the integrity check of a group of objects is usually done by looking up a packaging list or a shipment list in EDI, which requires a network connection. Our proposed “group coding” of RFID tags can perform the group integrity check without a network connection. In addition, when the integrity of the group is infringed, the group coding can determine the number of RFID tags missing from the group. These features of group coding can reduce the cost of looking up shipment lists and locate missing RFID tags. The accuracy of the determination is controlled by adjusting the size of data written in each RFID tag. Adopters of group coding can select the optimal performance of group coding from the requirements of the accuracy and constraints like memory consumption of RFID tags.

This paper proposes an adaptive Overlay Multicast protocol for real-time group communication in a heterogeneous environment. Overlay multicast technology relies on end nodes by delegating the multicast functionality from routers in IP Multicast. Overlay multicast research has two major issues to consider: heterogeneous resource environment and instability of end nodes. In our protocol, data is divided into multiple layers using abstract layered data structure. The number of layers is used for the main metric to construct the multicast tree to satisfy the demand for end nodes resource environment. Furthermore, multi-path layer distribution method for fast recovery from multicast tree partition and congestion avoidance method are proposed to deal with the unstableness at end node.

Efforts have been put for electronization of complementary currencies (alternative forms of monetary media) in the hope that it would reduce their operational cost. However, this paper argues that the problem is more inherent in the core design of MCS (mutual credit system), the most common form of complementary currency today. By simulating a small world of 2,500 traders, we show that growing the number of free-riders in MCS has a paradoxical effect of increasing "welfare" (a "happiness" metric) of the community. Since there is no pressure to stop the growth of the bad users, it is difficult to sustain the soundness of the system without strong interventions from the operators of the system; we need alternatives to the alternatives. We have proposed i-WAT as an electronic descendant of the WAT System, a polycentric complementary currency using "WAT tickets" as its media of exchange. A simulation using the same model as above indicates that i-WAT users can sustain barter relationships even in the presence of free-riders by natural evasive actions to avoid risks.

A P2P currency can be a powerful tool for promoting exchanges in a trusted way that make use of under-utilized resources both in computer networks and in real life. There are three classes of resource that can be exchanged in a P2P system: atoms (ex. physical goods by way of auctions), bits (ex. data files) and presences (ex. time slots for computing resources such as CPU, storage or bandwidth). If these are equally treated as commodities, however, the economy of the system is likely to collapse, because data files can be reproduced at a negligibly small cost whereas time slots for computing resources cannot even be stockpiled for future use. This paper clarifies this point by simulating a small world of traders, and proposes a novel way for applying the "reduction over time" feature of i-WAT, a P2P currency. In the proposed new economic order (NEO), bits are freely shared among participants, whereas their producers are supported by peers, being given freedom to issue exchange tickets whose values are reduced over time.

This paper proposes a novel technique to enable flow-level multi-path forwarding on IPv6 networks. Generally on such networks, any packet from a node is forwarded toward a destination along the same path, even if some of the packets belong to a different flow with different characteristics. In accordance with packet characteristics and to fulfil demands such as traffic engineering and QoS routing, flow-level multi-path forwarding allows explicit selection of the paths on which to send packets. Multi protocol label switching (MPLS) technology has been used to perform this function so far. However, to apply MPLS on an existing IPv6 network, all non-MPLS-enabled routers in the network must be replaced with MPLS-enabled routers. Therefore, the migration cost is generally expensive. Our previous work has proposed a technique called flow-mapping explicit host routing (FMEHR,), that renders similar results to MPLS using unused address spaces such as IP private addresses. This paper describes the FMEHR concept and its realization on an IPv6 network and discusses its characteristics.

This paper looks at the message implosion problem that may happen on large-scale reliable multicast communications. We propose that receivers track the senders of recent feedback messages and store them in a list to determine the back-off interval to send a feedback message. We call our proposal tracked sender list (TSL). The issues regarding this proposal are how many receivers to be stored in a receiver's list, back-off timer intervals, p.d.f selection, and how a receiver stores itself in its list. We analyzed and simulated our proposal using various parameters values in both networks with equal delay and with heterogeneous delays to show the message suppression performance. The results demonstrate that TSL gives a low number of messages over a wide range of receivers even with a short back-off interval and it is not susceptible to packet losses. Our results also show that TSL performs better than other p.d.fs that is used in message suppression.

While the IETF standardization process of the Mobile IPv6 and Network Mobility (NEMO) protocols is almost complete, their large-scale deployment is not yet possible. With these technologies, in order to hide location changes of the mobile nodes from the rest of the Internet, a specific router called a home agent is used. However, this equipment generates resilience and performance issues such as protocol scalability and longer paths. In order to solve these problems, we describe and analyze a new concept called Home Agent Migration. The main feature of this solution is the distribution of home agents inside the current Internet topology to reduce distances to end-nodes. As is usually done for anycast routing, they advertise the same network prefix from different locations; moreover they also exchange information about their associations with mobile nodes. This produces a Global Mobile eXchange (GMX), an overlay network that efficiently handles data traffic from and to mobile nodes, and operates home agents as would an Internet eXchange Point (IXP). When a correspondent node needs to exchange packets with a mobile node, the data traffic will be intercepted by its closest GMX home agent and redirected to the home agent to which the mobile node is bound.

The Virtual Mobility Control Domain (VMCD) is proposed to enhance mobility protocols such as Mobile IP and Network Mobility (NEMO). These mobility protocols rely on a single agent called the home agent. This leads to protocol weakness in terms of system robustness and redundant routes. In VMCD, multiple anchor points serving the same home network are placed as home agents at different networks on the Internet backbone. These anchor points advertise the route of the same home network to the backbone from different networks. It is similar to anycast routing approach of root DNS. By genuine routing, packets meant for mobile nodes are always drawn into the closest anchor point and are delivered to the mobile node by the anchor point on behalf of home agent. In addition, even if one of the anchor points fails, another anchor point immediately takes over for the failed anchor point. VMCD provides better routes for mobile nodes and protocol robustness with minimal involvement of end nodes. This paper discusses the VMCD solutions and shows the efficiency and effectiveness of VMCD.

In this paper, virtual mobility control domain (VMCD) is proposed to enhance mobility protocols such as mobile IP and network mobility (NEMO). These mobility protocols rely on a single agent called the home agent. This leads to protocol weakness in terms of system robustness and redundant routes. In VMCD, multiple anchor points serving the same home network are placed as home agents at different networks on the Internet backbone. These anchor points advertise the route of the same home network to the backbone from different networks. It is similar to anycast routing approach of root DNS. By genuine routing, packets meant for mobile nodes are always drawn into the closest anchor point and are delivered to the mobile node by the anchor point on behalf of home agent. In addition, even if one of the anchor points fails, another anchor point immediately takes over for the failed anchor point. VMCD provides better routes for mobile nodes and protocol robustness with minimal involvement of end nodes. This paper discusses the VMCD solutions and shows the efficiency and effectiveness of VMCD.

WIDE (Widely Integrated Distributed Environment) is a research project aimed at achieving a transparent distributed environment over heterogeneous distributed computing elements with the consideration of various types of connections for internetworking. The target environment of the research is computing environment in the academic and research communities especially in Japan.