• IE interfaces
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• v.11 no.1
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• pp.155-163
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• 1998

In multiparty multimedia communication, each participant not only receives information from other participants but also generates real-time data streams to distribute to others and therefore the difference between source and destination is not clear in terms of data transmission. During a teleconference session, many sub-multicast trees may be generated to exchange information to specific members within the multicast group and if those sub-multicast trees use the same fixed multicast tree, the blocking probability will be high and it is hard to provide QoS for each sub-multicast group. Also, even though there exits some shortcuts between each sub-multicast group, fixed multicast tree does not allow to use those shortcuts. Thus to overcome these problems. We propose a network resource reservation protocol and show that its effectiveness in terms of blocking probability and network resources usage.

• ETRI Journal
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• v.28 no.4
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• pp.517-520
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• 2006

In this letter, a new sharing mechanism, SRLG sharing, is proposed, which allows the links of the same shared risk link group (SRLG) in a primary light tree to share protections in WDM optical networks. In previous studies, how to share spare resources with SRLG constraints has not been studied in multicast optical networks. In this letter, considering SRLG sharing, we propose a novel algorithm -multicast with SRLG sharing (MSS)- to establish a protection light tree. Finally, the algorithm MSS and the algorithm multicast with no SRLG sharing (MNSS) are compared through a simulation to show that our new sharing scheme of SRLG sharing is more efficient than that of no SRLG sharing in terms of spare resource utilization and blocking probability.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.3
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• pp.81-89
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• 2000

The real-time multicast problem is to construct a multicast tree starting from a source node and including multiple destination nodes and that has minimum network cost with delay constraints. It is known that to find a tree of the minimum network cost is the Steiner Tree problem which is NP-complete. In this paper, we propose a genetic algorithm to solve the multicast tree with minimum network cost and the delay constraints. The computational results obtained by comparing an existing algorithm. Kompella algorithm, and the proposed algorithm show that our algorithm tends to find lower network cost on the average than Kompella algorithm does.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.5
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• pp.1-9
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• 2004

In this paper, we propose a multicast routing protocol for the seamless delivery of multicast data to mobile hosts through the optimal route in IPv6-Based mobile networks. The proposed multicast routing protocol reduces the tree reconstruction overhead by limiting the tunneling length according to the mobility of mobile hosts. In this way, our protocol satisfies the bound of the end-to-end delay and supports the seamless handoff. Analytical and simulation results show that the proposed protocol has better performance in terms of the tree reconstruction, tunneling service and multicast packet loss than the previous protocols does.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.2886-2896
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• 1996

The Type of Service based multicast routing algorithm is necessary to support efficiently herogeneous applications in ATM network. In this paper I propose the Constrained Multicast Tree with Virtual Destination(DMTVD) heuristic algorithm as least cost multicast routing algorithm. The service is categorized into two types, as delay sensitive and non in CMTVD algorithm. For the delay sensitive service type, the cost optimized route is the Minimum Cost Stenier Tree connecting all the destination node group, virtual destination node group and source node with least costs, subject to the delay along the path being less than the maximum allowable end to end delay. The other side for the non-delay sensitive service, the cost optimized route is the MCST connecting all the multicast groups with least costs, subject to the traffic load is balanced in the network. The CMTVD algorithm is based on the Constrained Multicasting Tree algorithm but regards the nodes branching multiple destination nodes as virtural destination node. The experimental results show that the total route costs is enhanced 10%-15% than the CTM algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1399-1406
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• 2009

In the internet broadcast, efficient and scalable mechanism of multicast is needed for the communication between groups. Furthermore, Optimization of the multicast tree is required to improve the performance of overlay multicast. This optimization is well-known as NP-complete. If a node in the tree has limited out-degree, a user who wants to join the group has to find parent user who has already joined. In this paper, the users who want to join the group need to setup their level using delay test from source node. And then new users can find candidate parent nodes effectively using ACK-SEND approach and take proper position by comparing level. The closer node of the user to root node should be located in lower level. Also, even if a barrier is caused, fast recovery will be guaranteed using ACK-SEND approach. Through this, the newcomer node can fine their location in the multicast tree and join the group fast and effectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6A
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• pp.600-610
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• 2010

In this paper, a multicast mechanism is proposed for intermittently disconnected networks where the nodes move forward in formation or within a limited area. The proposed scheme extends the well-known tree-based multicast routing mechanism called MAODV by modifying the tree construction and data delivery scheme. Especially, an algorithm is introduced which determines the flooding hop count k estimating the degree of the movement of children in the tree. The performance evaluation was done by the simulation and the proposed scheme was compared with MAODV and two multicast routing schemes for DTN (Disruption Tolerant Network) including the Epidemic routing and ST-multicast. The evaluation results show that our scheme improves the original MAODV from the aspect of tree reconstruction events and message delivery ratio. Compared with the Epidemic routing scheme, our scheme achieves 85% message delivery ratio with less than 50% message delivery overhead.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.234-243
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• 2000

We design a modified network architecture with condsidering current Internet network model and traffic characteristics, and propose EDCBT(Enhanced Dispersed Core-based Tree) multicast routing protocol, which enhances scalabity, reliability, end-to-end delay and resource utilization EDBCT adopts bidirectional dispersed shared trees and manages both of intradomain and interdomain multicast trees for a multicast group. Each regional multicast tree is estabilshed from its core router and they are interconnected by the operation between border routers on edges of each regional network. As a result, interdomain multicast tree can be easily established. We introduce a new concept named RBTS(Region-based Tree Switching), which dramatically enhances QoS and network utilization. Finally, protocol performance and the effect of core router location are evaluated with MIL3 OPNet network simulator, in terms of end-to-end delay, packet loss and throughput.

• Journal of Korea Game Society
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• v.2 no.1
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• pp.30-35
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• 2002

The deployment of multicast communication services in the Internet is expected to lead a stable packet transfer even in heavy traffic as in On-Line Game environment. The Core Based Tree scheme among many multicast protocols is the most popular and suggested recently. However, CBT exhibit two major deficiencies such as traffic concentration or poor core placement problem. So, measuring the bottleneck link bandwidth along a path is important for understanding the performance of multicast. We propose not only a definition of CBT's core link state that Steady-State(SS), Normal-State(NS) and Bottleneck State(BS) according to the estimation link speed rate, but also the changeover of multicast routing scheme for traffic overload. In addition, we introduce anycast routing tree, a efficient architecture for construct shard multicast trees.