Most wireless networks consist of heterogeneous nodes with diverse characteristics. These heterogeneous nodes have various moving characteristics such as speed and pausing time. Since conventional wireless routing schemes are designed for networks with homogeneous mobility, it is difficult to accomplish communication without degrading its quality, e.g., packet reachability and delay, in networks with heterogeneous mobility. In this paper, we propose efficient extensions of a proactive routing protocol to achieve sufficient communication quality in networks with heterogeneous mobility. The proposed extensions consist of three features, i.e., differential topology update, unidirectional movement notification and link quality based route calculation. Complementary actions among these functions can improve communication quality with acceptable control overhead. Simulation results reveal that the proposed scheme can achieve higher packet reachability and lower delay with low control overhead compared with existing routing schemes.

Communication infrastructures under the influence of the disaster strike, e.g., earthquake, will be partitioned due to the significant damage of network 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/NDN (Content-Centric Networking/Named-Data Networking) to information networks fragmented by the disaster strike. However, existing retransmission control in CCN is not suitable for the fragmented networks with intermittent links due to the timer-based end-to-end behavior. Also, the intermittent links cause a problem for cache behavior. In order to resolve these technical issues, we propose a new packet forwarding scheme with the dynamic routing protocol which resolves retransmission control problem and cache control scheme suitable for the fragmented networks. Our simulation results reveal that the proposed caching scheme can stably store popular contents into cache storages of routers and improve cache hit ratio. And they also reveal that our proposed packet forwarding method significantly improves traffic load, energy consumption and content retrieval delay in fragmented networks.

In research community of content distribution, a new communication paradigm of rendezvous-based abstraction which easily enables location-free content-oriented services, attracts great attention. ID/Locator separation architecture is originally proposed for resolving increase of routing table size in the current Internet but it has possibility of supporting this abstraction because host ID is clearly separated from its location. This feature of ID/Locator separation means an end host can be identified by ID independent of its network layer protocol. So, ID/Locator separation architecture enables communication with end host(s) operating different network-layer protocol, which might increase candidate paths between host pairs and improve content distribution path. 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. When multiple layer 3 networks are available for users, shortest path might be improved even only with multi-homing (without inter-layer 3 networking). We also evaluate shortest path improvement brought by multi-homing and inter-layer 3 networking for incremental deployment scenario of multi-homing. Our simulation results show that inter-layer 3 networking brings great improvement even with small number of users deploying multi-homing while only multi-homing itself brings small improvement.

Because of the popularity of rich content, such as video files, the amount of traffic on the Internet continues to grow every year. Not only is the overall traffic increasing, but also the temporal fluctuations in traffic are increasing, and differences in the amounts of traffic between peak and off-peak periods are becoming very large. Consequently, efficient use of link bandwidth is becoming more challenging. In this paper, we propose a new system for content distribution: storage aware routing (SAR). With SAR, routers having large storage capacities can exploit those links that are underutilized. Our performance evaluations show that SAR can smooth the fluctuations in link utilization.