Tomohiko Yagyu

Implementation and evaluation of a network-controlled mobility management protocol (IP/sup 2/MM): performance evaluation compared with mobile IPv6

The 3G mobile network IMT-2000, was launched some years ago and multimedia traffic in the mobile Internet has been increasing with the growth of wireless access links. Next-generation networks need to efficiently transport huge volumes of multimedia traffic with high-quality mobility management. We have proposed an IP-based IMT network platform (IP/sup 2/) for the next-generation mobile network architecture and have studied its mobility management scheme, IP/sup 2/ mobility management protocol (IP/sup 2/MM). IP/sup 2/MM is a network-controlled mobility protocol that deploys mobility functions inside the network and conceals IP mobility from the mobile node. It is also designed to satisfy the requirements of mobile operators. In this paper, we introduce an overview of IP/sup 2/MM and show the comparative evaluation results with mobile IPv6. For the evaluation, we implemented both in our experimental system and compared their performance. The results show that IP/sup 2/MM provides better mobility performance than mobile IPv6, and we conclude that IP/sup 2/MM is an effective and feasible mobility protocol for the next-generation networks of mobile operators.

The Benefit of Information Centric Networking for Enabling Communications in Disaster Scenarios

Information Centric Networking (ICN) is a new paradigm where the network provides users with named content, instead of communication channels between hosts. This document outlines some research directions for Information Centric Networking with respect to applying ICN approaches for coping with natural or human- generated, large-scale disasters. We argue that ICN approaches have many benefits for enabling (or continuing) communication after a disaster has impaired a communication network. In this context, we present key research challenges and an overview of our ongoing research activities for applying Information Centric Networking to address these challenges.

Moderator-Controlled Information Sharing by Identity-Based Aggregate Signatures for Information Centric Networking

Information sharing services have been provided via common servers, which not only relay messages but also sometimes moderate them. A peer can become a moderator and control the distribution of messages belonging to his private message group. However, the physical transfer of a message is usually out of the peers control. Originator-signed signatures inherent in Information Centric Networking assure the integrity and provenance of messages exchanged among peers, which makes it possible to realize moderator-controlled information sharing in which a peer can become a moderator and control the distribution of his private message group as a trustable server. However, moderated content requires multiple signatures, which increases the size of the exchanged message and is inadequate, especially for short message services. We propose the use of Identity-Based Aggregate Signatures (IBAS) to decrease this overhead, and provide a proof-of-concept IBAS implementation for Named Data Networking (NDN). We also compare the performance of the proposed IBAS implementation with existing RSA signatures. An overhead reduction of approximately 45% to 60% compared to RSA signatures is achieved for an NDN packet in the proposed configuration. Because of the properties of the identity-based signature, this IBAS implementation is robust and works even during a disaster or when a trustable centralized server is not online.

Demo overview: reliable contents retrieval in fragmented icns for disaster scenario

Aftermath of disaster, e.g., earthquake, existing communication infrastructure such as cellular networks will be severely damaged. A large number of user terminals suffer disconnection from central servers. Due to the fault of BaseStations(BS) and cable cut between BS and Backhaul, network is fragmented into portions. Because of the novel capabilities such as name-based communication and in-network caching, Information Centric Networking (ICN) is one of the promising technologies to support reliable communication among such fragmented parts of network. This demo presents dynamic name-based routing and reliable contents retrieval among fragmented networks with NDN (Named Data Networking) architecture in the context of disaster situation.

SMART:Scalable Mobility Adaptive Routing Techniques for Heterogeneous Mobile Networks

Most wireless networks consist of heterogeneous nodes with diverse characteristics. These heterogeneous nodes have various moving characteristics such as speed and direction. Since conventional wireless routing schemes are designed for networks with homogeneous mobility, they have to cope with the routing difficulties between heterogeneous nodes by careful tuning of routing parameters. Because optimally tuning to such parameters is difficult, this tuning tends to result in higher control overhead and to degrade communication quality, e.g., lower packet reachability and higher packet delay. This paper proposes efficient extensions of a proactive routing protocol to achieve sufficient communication quality in heterogeneous mobile networks. Simulation results reveal that the proposed scheme can achieve higher packet reachability and lower delay with low control overhead compared with existing routing schemes.

Name-based push/pull message dissemination for disaster message board

In the aftermath of natural disasters (e.g., earthquakes and hurricanes), information dissemination to and from citizens and authorities often involves the use of mobile network services. They may do so to seek help, distribute critical information, and possibly to confirm the safety of relatives and friends. The traffic on the cellular network typically increases substantially in the aftermath of such disasters. The situation is further compounded by disruptions caused by damage to the network infrastructure and the non-availability of power. Networks are fragmented, and communication is intermittent and disruption prone. In this paper, we propose a name-based many-to-many communication service for such fragmented networks. The key feature of this service is an integration of several communication methods, such as push-based and pull-based. The service effectively supports a variety of network situations by leveraging the features of information-centric networks.

Demo: Content-Based Push/Pull Message Dissemination for Disaster Message Board

Information Centric Networking (ICN) is one of the promising technologies to support reliable communication in the post-disaster network. This demo presents the integrated framework of push and pull type content-based communication, along with proposed enhancements that make it applicable in a disaster scenario. We will demonstrate these features with the help of an example application -- disaster message board.

Performance evaluation of path cost improvement in inter-layer 3 networking with ID/Locator separation architecture

ID/Locator separation architecture is proposed in order to reduce routing table size in the current Internet. In this architecture, an end-host can be identified by unique ID which is independent of its network protocol in use. This capability of identifying an end host with ID enables communication with end hosts operating different network-layer protocol. This inter-layer 3 networking brings another benefit of improvement of shortest path because it enables paths including other network(s) and increases candidate paths between host pairs. In this paper, we evaluate this improvement of shortest path brought by inter-layer 3 networking. In inter-layer 3 networking, a shared node connecting different network layer plane plays an important role. We evaluate shortest path improvement with various shared node locations and show that strategic assignment of shared nodes brings large improvement.

Energy and Bandwidth Efficient Content Retrieval for Content Centric Networks in DTN Environment

Communication infrastructures under the influence of the disaster strike e.g., earthquake, will be partitioned due to the damage of components such as base stations. The communication model of the Internet bases on a location-oriented ID, i.e., IP address, and depends on the DNS (Domain Name System) for name resolution. Therefore such damage remarkably deprives the reachability to the information. To achieve robustness of information retrieval in disaster situation, we try to apply CCN (Content-Centric Networking) to fragmented networks. Since CCN does not require name resolution, it can work without the global system such as DNS. However, existing retransmission control in CCN is not suitable for the fragmented networks with intermittent links due to the timer-based end-to-end scheme. Though the requirement to save energy and bandwidth are critical in disaster case, overhead caused by redundant retransmissions might waste bandwidth and energy. Accordingly, we propose the energy efficient retransmission scheme with the dynamic routing protocol suitable for fragmented networks. With the proposed method, messages are forwarded hop-by-hop with recognizing whether the state of links is connected or not. Simulation results reveal that the proposed method can reduce traffic load, energy consumption and delay of contents retrieval.

Multipath Support for Name-based Information Dissemination in Fragmented Networks

In the aftermath of natural disasters (e.g., earthquakes and hurricanes), networks are fragmented, and communication is intermittent and disruption-prone. In this paper, we propose a multipath support for publish/subscribe name-based information dissemination in such fragmented networks. Our solution helps to reduce unnecessary replication and transmission in disaster scenarios.