• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.269-286
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• 2011

In this paper, we study a problem that is concerning how to construct a delay-constrained multicast tree on a wireless mesh network (WMN) such that the number of serviced clients is maximized. In order to support high-quality and concurrent interference-free transmission streams, multiple radios are implemented in each mesh node in the WMNs. Instead of only orthogonal channels used for the multicast in the previous works, both orthogonal and partially overlapping channels are considered in this study. As a result, the number of links successfully allocated channels can be expected to be much larger than that of the approaches in which only orthogonal channels are considered. The number of serviced subscribers is then increased dramatically. Hence, the goal of this study is to find interference-free and delay-constrained multicast trees that can lead to the maximal number of serviced subscribers. This problem is referred as the MRDCM problem. Two heuristics, load-based greedy algorithm and load-based MCM algorithm, are developed for constructing multicast trees. Furthermore, two load-based channel assignment procedures are provided to allocate interference-free channels to the multicast trees. A set of experiments is designed to do performance, delay and efficiency comparisons for the multicast trees generated by all the approximation algorithms proposed in this study.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.1609-1615
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• 2006

Overlay multicast technique is an effective way as an alternative to IP multicast. Traditional IP multicast is not widely deployed because of the complexity of IP multicast technology and lack of application. But overlay multicast can be easily deployed by effectively reducing complexity of network routers. Because overlay multicast resides on top of densely connected IP network, In case of multimedia streaming service over overlay multicast tree, real-time data is sensitive to end-to-end delay. Therefore, moderate algorithm's development to this network environment is very important. In this paper, we are interested in minimizing maximum end-to-end delay in overlay multicast tree. The problem is formulated as a degree-bounded minimum delay spanning tree, which is a problem well-known as NP-hard. We develop tabu search heuristic with intensification and diversification strategies. Robust experimental results show that is comparable to the optimal solution and applicable in real time

• Current Optics and Photonics
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• 제1권5호
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• pp.456-467
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• 2017

The benefits of network coding in all-optical multicast networks have been widely demonstrated. In this paper, we mainly discuss the multicast service efficiently provisioning problem in the network coding enabled elastic optical networks (EONs). Although most research on routing and spectrum allocation (RSA) has been widely studied in the elastic optical networks (EONs), rare research studies RSA for multicast in the network coding enabled EON, especially considering the time delay constraint. We propose an efficient heuristic algorithm, called Network Coding based Multicast Capable-Multipath Routing and Spectrum Allocation (NCMC-MRSA) to solve the multipath RSA for multicast services in the network coding enabled EON. The well-known layered graph approach is utilized for NCMC-MRSA, and two request ordering strategies are utilized for multiple multicast requests. From the simulation results, we observe that the proposed algorithm NCMC-MRSA performs more efficient spectrum utilization compared with the benchmark algorithms. NCMC-MRSA utilizing the spectrum request balancing (SRB) ordering strategy shows the most efficient spectrum utilization performance among other algorithms in most test networks. Note that we also observe that the efficiency of NCMC-MRSA shows more obvious than the benchmark algorithm in large networks. We also conduct the performance comparisons of two request ordering strategies for NCMC-MRSA. Besides, we also evaluate the impact of the number of the linkdisjoint parallel w paths on the spectrum utilization performance of the proposed algorithm NCMC-MRSA. It is interesting to find that the change of the parameter w in a certain range has a significant impact on the performance of NCMC-MRSA. As the parameter w increases to a certain value, the performances of NCMC-MRSA cannot be affected by the change of w any more.

• 대한전자공학회논문지TC
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• 제46권6호
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• pp.37-47
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• 2009

본 논문에서는 IEEE 802.21 MIH (Media Independent Handover) 기반의 빠른 모바일 멀티캐스트 핸드오버 방식을 제안한다. 기존의 모바일 멀티캐스트 방식들이 L3 이동성 검출기반으로 하기 때문에 발생하는 문제점인 긴 멀티캐스트 핸드오버 지연시간 문제를 MIH를 확장한 멀티캐스트 아키텍쳐를 정의하여 해결한다. 본 논문에서는 MIH에 멀티캐스트 핸드오버를 효율적으로 수행하기 위한 멀티캐스트 메니저를 도입하고, 모바일 멀티캐스트를 위한 전용 MIH 메시지들을 추가한다. 또한, 멀티 캐스트 특성 상 핸드오버 뿐만 아니라 채널 잽핑 (zapping) 이벤트의 경우에도 네트워크를 선택해야하는 상황에 처하게 되므로 이를 고려하였다. 최적의 망을 선택함에 있어서 멀티캐스트 네트워크 선택 알고리즘을 단말의 속도와 AHP/GRA라고 하는 공정한 선택 알고리즘을 이용하여 설계한다. 마지막으로 시그널링 비용과 멀티캐스트 핸드오버 지연시간 측면에서 제안하는 아키텍쳐가 기존 방식들에 비해 가지는 장점을 시뮬레이션을 통해 증명한다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.312-315
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• 2006

Overlay Multicast is a promising approach to overcome the implementation problem of IP multicast. Real time services like internet broadcasting are provided by overlay multicast technology due to the complex nature of IP multicast and the high cost to support multicast function. Since multicast members can dynamically join or leave their multicast group, it is necessary to keep a reliable overlay multicast tree to support real time service without delay. In this paper, we consider path level reliability that connects each member node. The problem is formulated as a binary integer programming which maximizes the reliability of multicast tree. Tabu search based algorithm is presented to solve the NP-hard problem.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2196-2218
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• 2017

Multicast communication has been widely used in the Internet. However, multicast communication is vulnerable to DoS attack due to static router configuration. In this paper, HMC, a hopping multicast communication method based on SDN, is proposed to tackle this problem. HMC changes the multicast tree periodically and makes it difficult for the attackers to launch an accurate attack. It also decreases the probability of multicast communication being attacked by DoS and in the meanwhile, the QoS constrains are not violated. In this research, the routing problem of HMC is proven to be NP-complete and a heuristic algorithm is proposed to solve it. Experiments show that HMC has the ability to resist DoS attack on multicast route effectively. Theoretically, the multicast compromised probability can drop more than 0.6 when HMC is adopt. In addition, experiments demonstrate that HMC achieves shorter average multicast delay and better robustness compared with traditional method, and more importantly, it better defends DoS attack.

• ETRI Journal
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• 제29권4호
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• pp.524-526
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• 2007

In this letter, we study the multicast protection problem in sparse-splitting wavelength-division multiplexing (WDM) optical network, and propose a novel multicast protection algorithm called the shared source-leaf path-based protection (SLPP) algorithm. Unlike the proposals in previous studies, the backup paths derived by SLPP can share wavelength with the primary tree in sparse-splitting WDM networks. Simulations are used to evaluate the effectiveness of the SLPP algorithm.

• 한국정보통신학회논문지
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• 제6권2호
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• pp.248-256
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• 2002

본 논문에서는 WDM 단일홉 Broadcast-and-select망에서 멀티캐스트 서비스를 지원하기 위한 스케줄링 알고리즘을 제안하였다 기존의 멀티캐스트 스케줄링 알고리즘은 수신기의 이전상태를 고려하지 않는 방법이지만, 본 논문에서 제안하는 H-EAR, PGM 기법은 튜닝이 가능한 송신기와 수신기의 상태정보, 그리고 메시지전송시간과 튜닝지연시간을 이용하여 서브그룹을 나누는 알고리즘이며, 컴퓨터 시뮬레이션을 통해 제안된 알고리즘의 성능이 기존의 멀티캐스트 스케줄링 알고리즘에 비하여 지연시간과 서브 그룹수의 측면에서 우수함을 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.297-300
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• 2001

This paper proposes a sound multicast packet-switching method which can less affect QoS degradation. The method includes a switch fabric with extra switching paths dedicated for multicast packets. Presented also are both a buffering structure and a scheduling algorithm for the proposed method. Simulation analysis for the method shows that the switching delay of unicast packets is decreased even though arrival rate of multicast packets is increased.

• 인터넷정보학회논문지
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• 제5권5호
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• pp.129-138
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• 2004

스위치 노드(switch node)로 구성된 네트워크에서 멀티캐스팅을 위한 트리를 구성하는 것은 NP-complete로 알려진 스타이너 트리 문제(Stainer free problem)로 정형화된다. 현재의 멀티캐스트를 요구하는 서비스들은 대개 대용량의 멀티미디어 데이터를 요구하게 된다. 이러한 서비스들은 텍스트 기반의 서비스에 비해 서비스의 질(Quality of Service)이 아주 중요한 요소가 되고, QoS는 전송에 소요되는 시간에 매우 민감하게 반응한다. 단일 제약을 갖는 멀티캐스트 트리 문제에 적용되는 휴리스틱은 이미 많이 연구되었으나, 노드 연결도 제한과 평균 흡수를 고려하는 다중 제약이 있는 멀티캐스트 트리 문제에 적용되는 휴리스틱에 대한 연구는 없었다. 본 논문에서는 다중 제약을 만족하는 효율적인 멀티캐스트 트리 문제에 적용 가능한 알고리즘을 제안하고, 실험을 통하여 성능을 평가하였다.