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We propose on-demand spectrum resource allocation for elastic optical networks with multi-core fibers. We also introduce a simple crosstalk index and evaluate basic performance for blocking probability and spectrum overlap which causes inter-core crosstalk.
Recently, video streaming services using P2P(Peer-to-Peer) have attracted attention to solve the problem of load concentration on servers and reduce a lot of latency. Many P2P streaming systems, like Coolstreaming, however, have a complicated approach to control playback timings severely. And this leads to less churn resiliency and less adaptability to fluctuation of network traffic. Therefore, we...
In this paper, we propose a video data recovery method that exploits multiple streams. The proposed method gives priority to each data of multiple streams in terms of recovery from packet loss, and it is designed for recovering important data with higher probability. The priority of each data is calculated based on both inherent importance in one stream and loss probabilities of multiple streams....
Recently, optical network technologies are actively researched and developed. However, adaptive cooperation of optical network with network applications is not considered deeply. On the other hand, as a content distribution system, P2P(Peer-to-Peer) has attracted attention. Currently, content delivery with P2P is based on IP network, and its application to optical network has not been considered....
Application level multicast with multiple distribution trees is effective for real-time streaming in terms of low delay and jitter. However, failure of upstream nodes drastically influences on the performance of many downstream nodes in multiple tree-based multicast. This degradation of video data continues until reconstruction of distribution trees finishes. Therefore, it is important to recover...
Recently, network coding (NC) has been popularly applied to wireless networks in order to improve channel utilization. In wireless LANs, when NC is applied to packet retransmission, a base station can simultaneously retransmit multiple packets destined to different wireless stations for a single retransmission trial. On the other hand, NC creates additional packet delay at both base station and wireless...
In recent years, Wireless Sensor Network (WSN) which consists of a large number of sensor nodes having wireless communication and self-organizing capability receives much attention. The design of protocols for such networks has to be energy aware in order to prolong the lifetime of the network. Multi-hop and clustering communication are most efficient routing methods in WSN. Multi-hop communication...
In this paper, we propose a new service platform which provides stable QoS by allocating components dynamically with considering fault-tolerance. We assume that many kinds of components are running on component servers and each component has its own SLA. The proposed platform achieves to make a load-balancing system to meet SLA of these components SLA and considering the number of replications necessary...
Network services based on distributed components, which provide advanced network services with lower cost by assigning and reusing useful components running on remote nodes, are attracting increasing attention. In this service, when a component fails, a component that has the same function running on another node can be substituted for it. On the other hand, there are three kinds of failures in network...
Video distributions using TCP (called "TCP streaming") like YouTube have been increased rapidly with the improvement on the speed and capacity of the Internet. Thus, it is an important technical issue to guarantee QoS (quality of service) suitable for TCP streaming. However, it is difficult for the existing IP network to guarantee QoS of the TCP streaming. So far, in order to achieve the...
Multi-Channel MAC protocols increase network throughput because multiple data transfers can take place simultaneously. However, existing Multi-Channel MAC protocols do not take full advantage of the multi-channel environment, because they lack a mechanism allowing wireless stations to acquire vacant channel and time resources. In this paper, to achieve further throughput increase, we newly propose...
OPS (optical packet switching) networks are considered as one of promising candidates for new generation network architecture. However, optical RAM has not been realized yet. Hence, high packet loss probability is a serious issue on feasible OPS networks. Now, there are some ways to solve this issue. The first approach is the usage of congestion avoidance devices like wavelength converter, fiber delay...
To establish seamless and highly robust contents distribution technology in the environment of so-called multiserver contents distribution network, we focus on the Forward Error Correction (FEC) as an error recovery method, and we have proposed the new concept, Inter-Stream FEC, that means data recovery method between several streams by introducing redundant parity streams generated by inter-stream...
P2P live streaming distribution services which can reduce load of distributor becomes commonly. The contents of these services are provided by not only corporations but also individuals. In existing systems for business services, however, transmission load of distributor still remains in high level to keep quality of service higher. Thus, it is difficult for private content distributors to provide...
Programmable variable delay lines have been developed, so as to delay packets in variable durations by combining several lengths of FDLs in optical packet switch. In practice, two-stage switch with this programmable variable delay lines has been proposed. This switch has two buffers. One is the programmable variable delay lines (look-ahead buffer). The other is the fixed FDLs that re-input a packet...
In Multiple Fibers Optical Packet Switched (MF-OPS) networks, multiple data on one wavelength can be transmitted over multiple fibers. Therefore, it is important to consider the multiple fibers' resources in wavelength assignment problem. This paper focuses on this problem and proposes a wavelength assignment method smoothing available fiber resources for MF-OPS networks. As a result, the paper clarifies...
Recently, sensor network systems are gradually moving into heterogeneous designs, incorporating a mixture of variety kinds of sensor nodes. Many routing protocols have been proposed for sensor networks but most of them did not consider the non-uniform energy drainage caused by many-to-one traffic. In this paper we propose a clustering method for wireless sensor networks with heterogeneous node types...
We propose a programmable and scalable traffic management scheme. Programmable traffic management at high-speed routers is difficult because programmability and high-speed packet processing have involved a serious tradeoff. To attain both, the new scheme combines control programs at a control server and simple packet handling functions, such as sampling packet headers and discarding packets, at routers...
In optical packet switching networks, there are some limitations on the number of wavelength converters and the number of wavelengths which can be handled at edge nodes. Therefore, the packet loss tends to occur frequently at a certain hot-spot egress node. In this paper, we propose a novel method that reduces frequency of wavelength conversions on egress node by intentionally and adaptively converting...
Matrix type high-speed optical packet/burst switch is developed that shares high-cost devices for contention avoidance, such as tunable wavelength converters (TWCs) or fiber delay lines (FDLs). In such kind of architectures, there is a technical issue that an overloaded flow causes not only high packet loss probability of itself but also higher packet loss probabilities of other normal flows. We propose...
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