Yuki Koizumi

Adaptive Virtual Network Topology Control Based on Attractor Selection

One approach to accommodating traffic on a wavelength-routed optical network is to construct a virtual network topology (VNT) by establishing a set of lightpaths between nodes. To accommodate fluctuating traffic on a VNT, we propose an adaptive VNT control method, which reconfigures VNTs according to traffic conditions on VNTs, in IP over wavelength-routed wavelength-division-multiplexing networks. To achieve adaptability in the VNT control method, we focus on attractor selection, which models behaviors where biological systems adapt to unknown changes in their surrounding environments and recover their conditions. The biological system driven by attractor selection adapts to environmental changes by selecting attractors at which the system condition is preferable. Our VNT control method uses deterministic and stochastic behaviors and controls these two appropriately by simple feedback of the conditions of an IP network. By utilizing stochastic behavior, our new approach adapts to various changes in traffic demand with selecting suitable attractors, which correspond to VNTs in our method, for the current traffic demand. Moreover, to define feedback of the conditions on the IP network, our proposed scheme only uses load information on links, which is easily and directly retrieved and thus achieves quick responses to changes in traffic demand. The simulation results indicate that our VNT control method based on attractor selection quickly and adaptively responds to various changes in traffic demand, and our method adapts to at most twice larger changes in traffic demand than existing heuristic approaches.

Stability of virtual network topology control for overlay routing services

Overlay networks achieve new functionality and enhance network performance by enabling control of routing at the application layer. However, this approach results in degradations of underlying networks due to the selfish behavior of overlay networks. We discuss the stability of virtual network topology (VNT) control under overlay networks that perform dynamic routing updates. We find that the dynamics of routing on overlay networks cause a high fluctuation in the traffic demand matrix, which leads to significant VNT control instability. To overcome this instability, we introduce three extensions, hysteresis, two-state utilization hysteresis, and filtering, to VNT control. Simulation results show that the hysteresis mechanism improves network stability, but cannot always improve network performance. We therefore extend the hysteresis mechanism and show that it improves both network stability and performance. However, this extension requires a lot of time for the VNT to converge to a stable state. To achieve fast convergence, we use a filtering method for VNT control. Through simulations, we prove that our methods achieve stability against overlay routing without loss of adaptability for changes in traffic demand.

Application of attractor selection to adaptive virtual network topology control

The growth of the Internet and emerging application layer technologies causes numerous changes in network environments. Therefore, it becomes important to achieve adaptive methods of controlling networks in addition to optimizing their performance. To achieve an adaptive network control method, we focus on attractor selection, which models behaviors where biological systems adapt to unknown changes in their surrounding environments and recover their conditions. In this paper, we show the applicability of the attractor selection to the adaptive virtual network topology (VNT) control in IP over wavelength-routed WDM networks. The simulation results indicate that our VNT control method based on attractor selection quickly and adaptively responds to various changes in traffic demand.

Empirically modeling how a multicore software ICN router and an ICN network consume power

ICN (Information Centric Networking) has received much attention due to its built-in functionalities such as caching and mobility-support. One of the important research challenges is to reduce the power consumed by ICN networks because ICNs packet forwarding and packet-level caching are power-hungry. As the first step to achieve power-efficient ICN networks, this paper develops a power consumption model of a multicore software ICN router while taking into account the power consumed by power-hungry computation. This paper makes the following three contributions: First, the model is one of the first realistic models which consider ICN packet forwarding and packet-level caching. Second, the model is represented as a concise set of equations with just a few parameters. Third, we apply the model to estimate power consumed by simple networks.

VCCN: Virtual content-centric networking for realizing group-based communication

Data-centric networking has recently been getting increased attention. A representative design of data-centric networking is CCN (Content-Centric Networking), which routes packets within a network based on their content identifiers. CCN is basically designed to be open because ease of data reuse is one of the greatest advantages of data-centric networking. However, being used for real-world networking, completely open data-centric networking is not sufficient. It is required to realize closed communication within a group of users. In this paper, we propose Virtual Content-Centric Networking (VCCN), which realizes closed communication within a group of users with CCN router virtualization. This paper presents four building blocks of VCCN: extension of the content identifier, CCN router virtualization, packet transport between virtualized CCN routers, and Social Network Services cooperative user/group identification. Moreover, we implemented VCCNs basic features by extending the CCNx software and performed a preliminary performance evaluation of our VCCN implementation.

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.

On the stability of virtual network topology control for overlay routing services

Overlay networks achieve new functionality and enhance network performance by allowing routing to be controlled at the application layer. However, these approaches result in degradations of underlying networks due to the selfish behavior of overlay networks. In this paper, we investigate the stability of virtual network topology (VNT) control under the overlay networks that perform dynamic routing updates. We reveal that the dynamics of routing on overlay networks causes a high fluctuation in the traffic demand matrix, which leads to significant instability of VNT control. To overcome the instability induced by the overlay routing, we introduce hysteresis to the VNT control. Simulation results indicate that the hysteresis mechanism improves the network stability, but cannot always improve the network performance. We therefore extend the hysteresis mechanism and show that the proposed method improves both the network stability and the performance when the amount of traffic for overlay network is not large.

Proposal on routing-based mobility architecture for ICN-based cellular networks

Forthcoming 5G networks raise an important research issue of seamless mobility management of cellular and non-cellular networks. Adopting Information Centric Networking (ICN) architecture as common mobility management is promising because existing mobility management mechanisms are complicated and incur large signaling overhead. This paper designs a routing-based mobility architecture to provide seamless mobility for the both networks. The architecture consists of routing during longer duration and anchor-less forwarding during shorter duration. A main contribution of the paper is that the architecture is designed by carefully considering how to port it to cellular networks with as few modifications to them as possible.

Power Consumption Model of NDN-Based Multicore Software Router Based on Detailed Protocol Analysis

Named data networking (NDN) has received considerable attention recently, mainly due to its built-in caching, which is expected to enable widespread and transparent operator-controlled caching. One of the important research challenges is to reduce the amount of power consumed by NDN networks as it has been shown that NDNs name prefix matching and caching are power-hungry. As a first step to achieving power-efficient NDN networks, in this paper, we develop a power consumption model of a multicore software NDN router. By applying this model to analyze how caching reduces power, we report that caching can reduce power consumption of an NDN network if the power consumption of routers is in proportion to their load and the computation of caching is as light as that of forwarding.

Optimization of light-path configuration order in IP over WDM networks using fast traffic matrix estimation

We propose an algorithm for determining light-path configuration order to minimize the reconfiguration time from a disrupted state to a suboptimal state. It computes a near-optimal solution within one minute on a 1000-node network.