• Journal of Korea Game Society
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• v.4 no.4
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• pp.3-9
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• 2004

Expansion of internet and construction of high speed network which require multimedia services like MMORPG are exceeding the infra-structure. In this work, CBT is analyzed by focusing on the multicast routing protoco and the algorithm which is transformable to Anycast scheme from CBT scheme is suggested to adapt game traffic. Anycast routing scheme is suitable to distribute high density traffic. Simulation model was set per a number of group and group member, which enabled to reflect real environments. Performance evaluation of routing based on the characteristics of end-to-end delay of CBT and Anycast was mainly focused, The result showed that Anycast method was improved up 8.7%, 25.5%, 34.0%, 38.6% and 51.8%, 56.6% comparing with PIM-DM and CBT routing when packet site was 128, 512 and 1K byte respectively. From the simulation, CBT/Anycast routing scheme can be presented as a flexible and solid solution for the MMORPG traffic to improve the delay characteristics of game packets.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.457-465
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• 2007

Native information provider(IP) anycast suffers from routing scalability issues and the lack of stateful communication support. For this reason, we propose architecture for scalable and transparent anycast services(ASTAS), a proxy-based architecture that provides support for stateful anycast communications, while retaining the transparency offered by native anycast. Dynamic resource assignment for each initiated session guarantees that a connection is established with the most suitable target server, based on network and server conditions. Traffic engineering in the overlay can be realized in an effective way due to the dissemination of aggregated state information in the anycast overlay. To minimize the total deployment cost for ASTAS architectures, we propose optimized proxy placement and path finding heuristics based on look-ahead information gathered in network nodes. Contrary to a regular integer linear program(ILP) formulation, these heuristics allow to optimize proxy placement in large networks. A use case on a European reference network illustrates that lower proxy costs enable proxy deployment closer to the end-users, resulting in a reduced network load.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1624-1647
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• 2020

Vehicular network is one of the most important subjects for researchers in recent years. Anycast routing protocols have many applications in vehicular ad hoc networks. The aim of an anycast protocol is sending packets to at least one of the receivers among candidate receivers. Studies done on anycast protocols over vehicular networks, however, have capability of implementation on some applications; they are partial, and application specific. No need to say that the lack of a comprehensive study, having a strong analytical background, is felt. Mathematical modeling in vehicular networks is difficult because the topology of these networks is dynamic. In this paper, it has been demonstrated that vehicular networks can be modeled based on time-expanded networks. The focus of this article is on geographical anycast. Three different scenarios were proposed including sending geographic anycast packet to exactly-one-destination, to at-least-one-destination, and to K-anycast destination, which can cover important applications of geographical anycast routing protocols. As the proposed model is of MILP type, a decentralized heuristic algorithm was presented. The evaluation process of this study includes the production of numerical results by Branch and Bound algorithm in general algebraic modeling system (GAMS) software and simulation of the proposed protocol in OMNET++ simulator. The comprehension of the result of proposed protocol and model shows that the applicability of this proposed protocol and its reactive conformity with the presented models based on presented metrics.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.553-555
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• 2005

이중 공유기반 트리 방식인 CBT 방식은 송신자와 수신자 모두 센터 노드(Core)에 이르는 최단경로를 통해 데이터를 주고받는 방식이다. 이 방식은 Core를 이용하여 멀티캐스트의 한계인 확장성문제를 해결하기 위해서 사용된 방식이다. 그러나 현재 멀티미디어 라우팅방식은 Best-Effort 방식의 패킷 스위칭은 가능한 한 패킷을 전송하려 하기 때문에 Core와 RP를 중심으로 데이터의 폭주 현상을 유발한다. 우리는 이와 같은 문제를 해결하기 위해서 RED 알고리즘을 이용한 Anycast 방식을 제안한다. Anycast 프로토콜은 Anycast 주소를 가진 수신자 그룹 멤버들 중, 가장 근접한 라우터나 지역의 Anycast 그룹 멤버들에게 패킷을 재분배할 수 있는 최적의 서버 또는 호스트에게 패킷을 전달하는 방식이다. 이와 같이 Anycast는 Core의 패킷을 재분배하여 근접한 라우터로 재분배 하여 최적의 호스트에게 전달할 수 있다. Core의 패킷을 재분배하기 위해서는 RED 알고리즘을 도입하여 Core으 트래픽 증가를 분산시킨다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.125-128
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• 2022

As the number of online systems based on the internet gradually increases, cyber-scale attacks that interfere with the normal operation of web services are also on the rise. In particular, distributed denial-of-service attacks (DDoS) that interfere with normal web service operations are also increasing. Therefore, this paper presents an efficient DDoS attack defense technique utilizing Equal Cost Multi-Path (BGP ECMP) routing techniques in networks of Anycast type by operating PoP basis of major attack sources and describes how high-availability web services can be operated.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.683-687
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• 2010

In this paper, we propose an anycast routing scheme for large-scale wireless mesh networks, which requires only one-hop local information with no flooding overhead. We develop an analytical model for anycast mesh networks based on an electrostatic theory. A finite difference method contributes to achieving gateway load balancing with constant control overheads. We verify the performance of the proposed scheme by simulations.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.607-607
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• 2006

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.213-215
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• 2003

Multimedia has to carry data of heterogeous types. Multicast communication techniques can supply the most appropriate infrastructures to such multimedia. Of many multicast protocols, the core based tree (CBT) protocol is the most concentrative studies are conducted on. The CBT places a core router at center of the shared tree and transfers data through the tore router. However, the CBT has two problems due to centralizing all network traffics into a core router. First it can raise bottleneck effect at a core router. Second, it is possible to make an additive processing overhead when core router is distant from receivers. To cope with the problems, this paper proposes an intelligent anycast routing protocol. The anycast routing attempts to distribute the centralized traffic into plural core routers by using a knowledge-based algorithm. The anycast routing estimates the traffic characteristics of multimedia data far each multicast source, and achieves effectively the distributing that places an appropriate core router to process the incoming traffic based on the traffic information in the event that request of receivers are raised. This method prevent the additional overhead to distribute traffic because an individual core router uses the information estimated to multicast sources connected to oneself and the traffic processing statistics shared with other core neuters.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.79-85
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• 2017

Vehicular ad-hoc networks (VANETs) cause link disconnection problems due to the rapid speed and the frequent moving direction change of vehicles. Link disconnection in vehicle-to-vehicle communication is an important issue that must be solved because it decreases the reliability of packet forwarding. From the characteristics of VANETs, greedy forwarding protocols using the position information based on the inter-vehicle distance have gained attention. However, greedy forwarding protocols do not perform well in the urban environment where the direction of the vehicle changes greatly. It is because greedy forwarding protocols select the neighbor vehicle that is closest to the destination vehicle as the next transmission vehicle. In this paper, we propose a greedy anycast forwarding (GAF) protocol to improve the reliability of the inter-vehicle communication. The proposed GAF protocol combines the greedy forwarding scheme and the anycast forwarding method. Simulation results show that the GAF protocol can provide a better packet delivery rate than existing greedy forwarding protocols.

• Journal of Game and Entertainment
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• v.2 no.1
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• pp.8-16
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• 2006

The development of multicast communication services in the Internet is expected to lead a stable packet transfer even though On-Line Games generate heavy traffic. The Core Based Tree scheme among many multicast protocols is the most popular and suggested recently. However, CBT exhibits two major deficiencies traffic concentration or poor core placement problem. Thus, measuring the bottleneck link bandwidth along a path is important to understand the performance of multicast. We propose a method in which the core router's state is classified into SS(Steady State), NS(Normal State) and BS(Bottleneck State) according to the estimated link speed rate, and also the changeover of multicast routing scheme for traffic overload. In addition, we introduce Anycast routing tree, an efficient architecture for constructing shard multicast trees.