• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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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

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.171-192
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• 2017

The change of any element in the network is possible to cause performance degradation of the multicast network. So it is necessary to optimize the topology path through the multicast update strategy, which directly affects the performance and user experience of the overlay multicast. In view of the above, a new multicast tree update strategy based on perturbation theory Musp (Multicast Update Strategy based on Perturbation theory) is proposed, which reduces the data transmission interruption caused by the multicast tree update and improves user experiences. According to the multicast tree's elements performance and the topology structure, the Musp strategy defines the multicast metric matrix and based on the matrix perturbation theory it also defines the multicast fluctuation factor. Besides it also demonstrates the calculability of the multicast fluctuation factor presents the steps of the Musp algorithm and calculates the complexity. The experimental results show that compared with other update strategies, as for the sensitivity of the multicast fluctuation factor's energized multicast tree to the network disturbance, the maximum delay of the Musp update strategy is minimal in the case of the local degradation of network performance.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1355-1358
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• 2001

IP Multicast can efficiently provide enormous bandwidth savings by enabling sources to send a single copy of a message to multiple recipients who explicitly want to receive the information. But due to the complexity of IP multicast and its fundamental differences from unicast, there are not very many tools available fer monitoring and debugging multicast networks, and only a few experts understand the tools that do exist. This thesis proposes a Multicast Routing Debugger (MRD) system that monitor the status of a multicast network. This system is aimed to multicast-related faults detection. In thesis, first, we define the set of information that should be monitored. Second, the method is developed to take out such information from multicast routers. Third, MRD system is prototyped to collect, process information from heterogeneous routers on a multicast network and to display the various status of the network comprehensively. The prototype of MRD system is implemented and deployed. We perform experiments with several scenarios. Experimental results show we can detect various problems as information that we define is monitored. The MRD system is simple to use, web-based and intuitive tool that can monitor the status of a specific multicast network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3138-3150
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• 2021

Multimedia services on the Internet are continuously increasing. Accordingly, the demand for a technology for efficiently delivering multimedia traffic is also constantly increasing. The multicast technique, that delivers the same content to several destinations, is constantly being developed. This technique delivers a content from a source to all destinations through the multicast tree. The multicast tree with low cost increases the utilization of network resources. However, the finding of the optimal multicast tree that has the minimum link costs is very difficult and its calculation complexity is the same as the complexity of the Steiner tree calculation which is NP-complete. Therefore, we need an effective way to obtain a multicast tree with low cost and less calculation time on SDN-based smart network platforms. In this paper, we propose a new multicast tree generation algorithm which produces a multicast tree using an agent trained by model-based meta reinforcement learning. Experiments verified that the proposed algorithm generated multicast trees in less time compared with existing approximation algorithms. It produced multicast trees with low cost in a dynamic network environment compared with the previous DQN-based algorithm.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.307-315
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• 2003

This paper proposes a Multicast Tree Extension (MTE) scheme for multicast in IP-based wireless networks. If a group receiver Joins a multicast group in a visited foreign network, multicast service may be disrupted when the foreign network does not have a multicast router. To avoid disruption, our scheme creates a bi-directional tunnel between the previous foreign agent (FA) and new foreign agent, if a mobile node (MN) moves from a foreign network with multicast capability to another foreign network with non-multicast capability. The MN thus continues to receive the multicast packets through the tunnel from the previous FA. Our scheme can avoid a long latency due to a long tunneling for group membership as well as multicast service disruption, even if the MN enters foreign networks with non-multicast capability. Simulation results show that our scheme offers lower costs for multicast delivery, tunneling and handoff latency than the existing scheme.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.557-566
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• 2008

NGN(Next Generation Network) is a communication network which can make use of broadband and QoS-enabled transport technologies. One of the main service issues over NGN is a multimedia service, such as IPTV, using a multicast method. And overlay multicast technology is one of the promising solutions instead of traditional multicast technology which has a few problems, and supports flexibility and scalability for multicast services. Also, the main controversial topic in NGN and overlay multicast is QoS. In the present paper, we designed an agent in each receiver's network, and a manager which is in a source network and which manages the whole multicast network. Both of them are communicating with each other and applying resource policies to their multicast network. This mechanism enables overlay multicast to support QoS, focusing on RACF(Resource and Admission Control Functions) in NGN QoS architecture.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.17-23
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• 2007

The home network has been revitalized due to the emergence of the high-speed broadband network and explosive increases of the home network services. Especially multicast based high-definition (HD) IPTV service is on high demand from both Internet service provider (ISP) and users. In order to provide high quality HD IPTV service without packet loss and delay, the ISP utilizes various network QoS mechanisms. Due to the misleading fact, that the home gateway is considered as an end terminal in terms of the ISP's viewpoint, the ISPs can not guarantee the end-to-end QoS within the scope of the current home network architecture. Therefore, an independent QoS guaranteed mechanism should be considered within the home network domain. As the home gateway manages both private home and public access network within the home network, we propose and implement a novel QoS mechanism for the multicast based HD IPTV service over the home gateway. In order to provide QoS guaranteed HD IPTV service, the proposed mechanism classifies the packets, manages home network bandwidth resources, and executes call admission control using the channel join message. Also, we utilize layer 2 multicast packet forwarding scheme to improve the overall performance of the home network services. Through the experiments of implementing the multicast based HD IPTV services, we will verify the efficiency of the proposed mechanism.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.76-78
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• 2002

Multicasting over mobile IP network becomes more important with the increasing needs of supporting multimedia services in mobile network. The IETF has suggested two approaches which are remote subscription and bidirectional tunneling for supporting mobility management in multicasting over mobile IP. But these protocols have problems - the frequent reconstruction of multicast delivery tree, packet less during handoff, convergence problem, and so on. In this paper, we propose to use preconfiguration of multicast delivery tree when mobile host enters the foreign network. It will decrease the frequency of multicast delivery tree reconstruction, and reduce the packet loss during handoff, Also the multicast delivery tree maintained by Keep Alive messages makes the signaling overload of networks diminished.

• ETRI Journal
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• v.34 no.5
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• pp.775-778
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• 2012

We propose integrating random network coding with the Enhanced On-Demand Multicast Routing Protocol (E-ODMRP). With the Network Coded E-ODMRP (NCE-ODMRP), we present a framework that enables a seamless integration of random linear network coding with conventional ad hoc multicast protocols for enhanced reliability. Simulation results show that the NCE-ODMRP achieves a nearly perfect packet delivery ratio while keeping the route maintenance overhead low to a degree similar to that of the E-ODMRP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1037-1050
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• 2000

A goal of a BISDN network is to provided integrated transport for a wide range of applications such as teleconferencing, Video On Demand etc. There require multipoint communications in addition to conventional point-to-point connections. Therefore multicast capabilities are very essential in multimedia communications. In this paper, we propose a new multicast cell scheduling method on the Parallel Multicast Packet Switch with Ring network: PMRN which are based on separated HOL. In this method, we place two different HOLs, one for unicast cells and the other for multicast cells. Then using non-FIFO scheduling, we can schedule both unicast cells and multicast cells which are available at the time in the input buffer. The simulation result shows that this method reduces the delay in the input buffer and increases the efficiency of both point-to-point network and ring network and finally enhances the bandwidth of the overall packet switch. A goal of a BISDN network is to provided integrated transport for a wide range of applications such as teleconferencing, Video On Demand etc. There require multipoint communications in addition to conventional point-to-point connections. Therefore multicast capabilities are very essential in multimedia communications. In this paper, we propose a new multicast cell scheduling method on the Parallel Multicast Packet Switch with Ring network: PMRN which are based on separated HOL. In this method, we place two different HOLs, one for unicast cells and the other for multicast cells. Then using non-FIFO scheduling, we can schedule both unicast cells and multicast cells which are available at the time in the input buffer. The simulation result shows that this method reduces the delay in the input buffer and increases the efficiency of both point-to-point network and ring network and finally enhances the bandwidth of the overall packet switch.