• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.396-400
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• 2011

P2P(peer to Peer) network is a distributed network architecture composed of participants that make a portion of their resources directly available to other network participants, without the need for a central server. Currently, convergence network industry using wired and mobile are grows rapidly. So P2P protocols will be used between mobile and wired network. But current P2P protocols are focused on the wired networks only and there are no simulators for performance analysis of mobile P2P. In this paper, we design a P2P simulation system for performance analysis of P2P protocols in mobile, wired and convergence networks. It is constructed by a well-known mobile network simulator and wired based P2P protocol simulator. Finally we have implemented a smart TV test-bed using our P2P test-bed for convergence networks.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.295-300
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• 2010

Recent researches of network structure are moving to high-level networks because there are already many research results of low-level network. Especially, current network services has been changed to the multimedia service using multicast routing such as IPTV(Internet Protocol Television) service. And then previous multicast services were provider oriented. So previous multicast structures were organized server/client model. But future multicast services will make user oriented services. Therefore there will be many service providers in the future. At this point, we study P2P network for supporting multi provider. So we research load balancing and contents lookup protocols in P2P network. In this paper, we propose network protocol and system based on super peer P2P for load balancing and efficiently service search. And we considered mobile environment for mobile IPTV.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.21-28
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• 2005

최근의 제 2 세대 P2P 시스템은 확장성 있고 장애에 강한 분산 해쉬 테이블을 이용하여 대규모 P2P 애플리케이션을 위한 셀프-오거나이징 (Selforganizing)기술을 제공한다. 하지만 기존의 Pastry의 경우 해쉬 기반 기법을 적용하였기 때문에 사용자들의 요청이 빈번한 콘텐츠의 경우 한 노드로 네트워크의 전송 부하가 집중되는 현상이 발생할 수 있어 CDN 시스템에 적합하지 않았다. 본 논문에서는 이러한 문제점을 해결하기 위하여 CDN(Content Delivery Network) 환경에 적합하게 확장한 Rosary 오버레이 네트워크를 제안한다. 본 논문에서 제안하는 Rosary는 Pastry를 Inter-Pastry와 Intra-Pastry로 나누어 CDN 환경에 맞게 확장하였고 애플리케이션-레벨 멀티캐스팅(Applicatio-Level Multicasting)을 가능하도록 했으며 세미 해쉬 스킴(Semi Hash Scheme)을 적용함으로서 CDN 환경에 맞게 수정 하고 확장하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.573-576
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• 2011

Research on 4A(Any-time, Any-where, Any-device, Any-contents) services for the next-generation multimedia services is developed with the trend of the integration of wire and wireless networks and the convergence of telecommunications and broadcasting. In this paper we proposed a design of SVC(Scalable Video Coding) overlay multicast mechanism which can provide typical next-generation multimedia services such as SVC streaming. A novel overlay multicast algorithm called ACK-Flow tree optimization algorithm is proposed to guarantee SVC streaming with high efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1098-1107
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• 2011

As recent integration of wire and wireless networks and the convergence of telecommunications and broadcasting, uniform and standardized by the broadcasting operators of existing stations to provide 4A(Any-time, Any-where, Any-device, Any-contents) services for the next-generation of multimedia services research is being progressed. Demand for theses next-generation multimedia services to ensure video compression coding technology, as well as mobility, ability to operation a variety of devices, characteristics and performance of user network and the status and conditiion, user preferences and context-awareness based on the technology has an interest in technical studies. In this paper, the current internet environment, SVC(Scalable Video Coding) encoded by a mixture of multicast and overlay multicast transmission technology for broadcasting services by designing and efficient multimedia broadcasting system is proposed. In addition, ACK-Aow Optimization by overlay multicast scheme existing tree-based overlay multicast, and by comparing the effectiveness of the proposed algorithm is demonstrated.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.653-660
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• 2009

A research for middleware of WSN can provide sensor applications with avoiding tight coupling of hardware, ease of development, and abstract data access. However, previous works have some limitations which should install their own middleware onto the all sensor nodes resulting in computational and communication overhead. In order to address it, we proposed a virtual sensor overlay network, called TinyONet-Lite which introduced virtual sensors to model a virtual counterpart of physical sensors. These virtual sensors dynamically grouped into an overlay network, Slice, which provides middleware services. We implemented TinyONet-Lite on mote class hardware with TinyOS. In accordance with experiments and comparison with existing researches, TinyONet-Lite was proved to show advantages of extensibility, dynamic service composition and reducing overhead.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.55-63
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• 2007

Multicast is an efficient transport mechanism for community communications and MANET is recently regarded as a promising solution for support ubiquitous computing as an underlying network technology. However, it is hard to deploy multicast mechanism into MANET owing to scarce resources in wireless networks and unpredictable changes in network topology. Several multicast mechanisms have been proposed in the literature to overcome the limitations. Especially, overlay multicasting schemes present several advantages over network based multicasting schemes. Yet, the overlay multicasting schemes still introduce redundant data transmissions that waste network bandwidth and battery of relay nodes. As a result the performance of the network is degraded. To reduce the redundancy, we propose an efficient way to construct an overlay structure as a multicast data delivery tree that utilizes a branch node which belongs to the tree. By using network simulation, we show that the proposed scheme presents higher packet delivery ratio and lower transmission cost than previously proposed schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.567-574
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• 2013

Recently, many researches on P2P overlay network-based multimedia streaming services have been actively performed because of their high scalability and cost-efficiency advantages. However, P2P overlay networks also have the shortcoming of generating higher traffic owing to their unicast-based one-to-many multimedia deliveries. In order to reduce the traffic generated by the P2P streaming overlay network, we propose an ISP and locality-based parent node discovery method and check its feasibility through an implementation of a prototype streaming system. The measurement of RTTs and hop counts for random nodes having different ISPs and localities shows the proposed method to be able to shorten about 32% RTTs and about 17% Hop counts.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2286-2309
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• 2016

Overlay networks have been widely deployed upon the Internet by Service Providers (SPs) to provide improved network services. However, the interaction between each overlay and traffic engineering (TE) as well as the interaction among co-existing overlays may occur. In this paper, we adopt both non-cooperative and cooperative game theory to analyze these interactions, which are collectively called hybrid interaction. Firstly, we model a situation of the hybrid interaction as an n+1-player non-cooperative game, in which overlays and TE are of equal status, and prove the existence of Nash equilibrium (NE) for this game. Secondly, we model another situation of the hybrid interaction as a 1-leader-n-follower Stackelberg-Nash game, in which TE is the leader and co-existing overlays are followers, and prove that the cost at Stackelberg-Nash equilibrium (SNE) is at least as good as that at NE for TE. Thirdly, we propose a cooperative coalition mechanism based on Shapley value to overcome the inherent inefficiency of NE and SNE, in which players can improve their performance and form stable coalitions. Finally, we apply distinct genetic algorithms (GA) to calculate the values for NE, SNE and the assigned cost for each player in each coalition, respectively. Analytical results are confirmed by the simulation on complex network topologies.

• Journal of Communications and Networks
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• v.7 no.1
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• pp.76-86
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• 2005

Today's wireless access networks consist of several tiers that overlap each other. Provisioning of real time undisrupted communication to mobile users, anywhere and anytime through these heterogeneous overlay networks, is a challenging task. We extend the end-to-end approach for the handoff management in hybrid wireless data network by designing a fully mobile-controlled handoff for mobile devices equipped with dual mode interfaces. By handoff, we mean switching the communication between interfaces connected to different subnets. This mobile-controlled handoff scheme reduces the service disruption time during both horizontal and vertical handoffs and does not require any modification in the access networks. We exploit the IP diversity created by the dual interfaces in the overlapping area by simultaneously connecting to different subnets and networks. Power saving is achieved by activating both interfaces only during the handoff period. The performance evaluation of the handoff is carried out by a simple mathematical analysis. The analysis shows that with proper network engineering, exploiting the speed of mobile node and overlapping area between subnets can reduce service disruption and power consumption during handoff significantly. We believe that with more powerful network interfaces our proposal of dual interfaces can be realized.