This paper presents a new network architecture called LINA that provides node mobility. The basic concept of LINA is separation of the node identifier and the interface locator. Although there are several protocols based on such a concept, they do not address issues that arise when dealing with an entire network architecture. LINA is a holistic architecture covering the network layer to the application layer in order to support node mobility. Overhead incurred by separation of the node identifier and the interface locator is minimized in LINA by introducing the embedded addressing model. This paper also presents a new protocol called LIN6 that supports IPv6 mobility. LIN6 is an application of LINA to IPv6 and is fully compatible with IPv6. It has several advantages in comparison to Mobile IPv6, e.g. less protocol overhead. Our prototype implementation of LIN6 shows minimal overhead compared to a conventional IPv6 implementation.

Layering architecture of the Internet Protocol provides independent processing for each layer by concealing state information from each layer. Application Program Interface (API) is based on the idea of layering model. However, the idea disturbs efficient processing of applications requiring adaptation to network environment, such as context-aware applications in mobile computing. To address this need, this paper proposes MIBsocket designed as an integrated control and management system for general network information. Any variable information related to network is shared between each applications and operating system. MIBsocket detects and informs changes in network resources to applications. MIBsocket functions such as Get, Set, and Trap used in the application adapts dynamically to any environments. MIBsocket provides portability and facility for applications: it only requires a few modification to the operating system and its API has the same programmable interfaces as usual API's. MIBsocket does not interfere the current layering architecture, but it achieves remarkable improvement on the current model. We have measured costs of MIBsocket, and applied MIBsocket to the application named interface switching system which enables a mobile host to connect to the Internet anytime by switching interface depending on network environment. As a result, the costs of MIBsocket was found acceptable. The application shows that MIBsocket is useful for movement detection and reconfiguration of network resources in the mobile computing.

In this paper, we discuss the performance of a basic scheme to support network mobility. Network mobility arises when an entire network segment, such as a network inside a vehicle, changes its topological location and thus its access point to the fixed backbone network. Mechanisms to support network mobility are necessary to maintain sessions. The approach followed by the IETF (NEMO Basic Support) and us (B-ORC) is to establish a bi-directional tunnel between the mobile network and the Internet. As we show, this bi-directional tunnel is a performance bottleneck and leads to single points of failure. In order to address the issues of the existing mobile network architecture, we propose enhanced operations of the basic mobile network protocol to achieve reliability and efficiency: (1) multiple bi-directional tunnels between the mobile network and the Internet, and (2) policy-based routing. The proposed operations could be realized by extending the existing architecture and protocol. The performance of various multihoming configurations is evaluated based on the implementation of our own basic scheme. The evaluation criteria are delay, throughput and latency. The results are encouraging and show we can achieve a better throughput.

On the Internet, two different IP protocols are deployed such as IPv4 and IPv6. The Mobile Router uses the basic NEMO protocol which is IPv6 protocol specific. During the early period of time that IPv6 transition is occurring it is very likely that a Mobile Router will move to an IPv4 only access network. When this occurs the Mobile Router will no longer be able to operate using the basic NEMO protocol. There has already been some earlier work to provide IPv6 capability over an IPv4 access network for a Mobile Router. This paper provides a capability by to maintain IPv6 connectivity for the Mobile Router via its Home Agent with IPv4-in-IPv6 encapsulation with no special boxes to be deployed elsewhere in the network.

In disaster sites of 2011 Tohoku Earthquake, digital communication was virtually unavailable due to the serious damage to the existing Internet and ICT resources. Thus there were urgent demands for recovering the Internet connectivity and first aid communication tools. This paper describes the design and deployment of networking systems that provide Internet connectivity using 3G mobile links or VSAT satellite links. In this paper we examine two approaches for post-disaster networking: quickly deployable package and on-demand networking. Based on a comparison of their characteristics and deployment experiences, this paper tries to extract lessons that contribute to improving the preparedness to another disaster. This paper also shares our significant operational experience acquired through supporting a maximum of 54 sites in Tohoku area including evacuation shelters, temporary hospitals and local government offices.