• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1113-1122
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• 1999

In this paper, we propose MSS(Multicast Synchronization Server) and QCS(QoS Conversion Server) models that can support IP multicast and QoS(Quality of Service) over the ATM network more efficiently. In the MSS model, it is possible to establish shortcut VCs(Virtual Circuits) among all hosts in the ATM network and to transfer multicast data at high speed. Also the MSS model is more scalable, because the number of inter-cluster VCs needed in the MSS model is less than that of EARTH. In the QCS model, ATM switch is modified to support one QoS service and best effort service through the one point-to-multipoint VC at the same time so required network resources are reduced, and dedicated server is used for QoS conversion to accept heterogeneous receivers more efficiently. In this Paper, the proposed MSS model and QCS model have solved both efficiency problem and scalability problem. It is proved through the comparison of the VCs required in each model.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.537-544
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• 2010

The PMIPv6 is a network controlled mobility management protocol in which mobile nodes never participate in IP mobility protocol signaling. One issue in using PMIPv6 for multicast service is that a new component should be added as the mobility management functions are located not on the device but on the network. Currently, standardization activities for providing muticast services with PMIPv6 have been actively in progress. This paper addresses some issues about the on-going standardization works for providing efficient real-time multicast services with PMIPv6, and proposes a scheme for minimizing hand over delays and packet losses by using a new neighbor cell reporting method. The proposed scheme has been verified to outperform the existing scheme in hand over delay and packet loss perfonnrmces by using computer simulations.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.611-620
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• 2001

To meet the requirements of reliable service for various applications, a Reliable Multicast Transport Protocol should be implemented over IP Multicast where currently best-effort service is provided. Among the current researches, hierarchical tree-based mechanism has been proposed and actively studied. This mechanism is known to provide high scalability as well as reliability, but needs an additional tree configuring mechanism for building an efficient logical tree in transport layer. Bottom-up approach has been used for creating such a tree. This method has benefits from parallel tree construction for receivers, while it has some drawbacks such that it does not guarantee a loop-free tree and brings heavy message overhead during tree creation process. Therefore, this paper proposes a top-down based mechanism for constructing a control tree, which can guarantee loop-freeness by step-wise mannered tree building. From experimental simulations, it shows that the proposed mechanism has less message overhead. It is recommended that the bottom-up and the proposed top-down will be selectively used in real networks, according to the requirements of the concerned multicast applications.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.573-586
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• 2008

The improved performance and miniaturization of computer and the improvement of wireless communication technology have enabled the emergence of many high quality services. Among them multicast services are receiving much attention and their usage is increasing due to the increase of Internet multimedia services such as video conference, multimedia stream, internet TV, etc. Security plays an important role in mobile multicast services. In this paper, we proposed a secure multicast protocol for a hierarchical micro-mobility environment. The proposed secure multicast protocol provides security services such as authentication, access control, confidentiality and integrity using mechanisms including symmetric/asymmetric key crypto-algorithms and capabilities. To provide forward/backward secrecy and scalability, we used sub-group keys based on the hierarchical micro-mobility environment. With this security services, it is possible to guard against all kinds of security attacks performed by illegal mobile nodes. Attacks executed by internal nodes can be thwarted except those attacks which delete packet or cause network resources to be wasted. We used simulator to measure the performance of proposed protocol. As a result, the simulation showed that effect of these security mechanisms on the multicast protocol was not too high.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.447-449
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• 1998

본 논문에서는 ATM망에서 IP멀티캐스트를 지원하기 위한 방법을 소개하고. 이를 바탕으로 좀더 효율적으로 IP 멀티캐스트를 지원하기 위한 방법을 제안하였다. Intra-cluster 멀티캐스트에 기반을 둔 MARS 모델은 IP멀티캐스트를 효율적으로 지원하지 못하며, 전체 망을 하나의 서버로 관리하는 EARTH 모델은 모든 처리가 서버로 집중되어 확장성 및 관리에 어려움이 있다. 본 논문은 효율적인 데이터 전송이 가능하면서 동시에 확장이 용이하도록 MARS 프로토콜을 확장하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.575-581
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• 1998

In order to accommodate current accelerated growth in customers and traffic. Internet has faced the demand to scale its network dimension both in size and bandwidth, and new service provisioning. One way to solve this problem is to forward If packets based on ATM switching technology. This paper briefly explained technical tasks to apply this If switching technique in ATM networks for building Internet backbone, and presented the directions to approach these tasks. Those tasks are scalability, ATM VC setup and mapping between VC and IP packet flow, traffic management and traffic engineering, multicast, and finally ATM switch architecture to provide multiservice.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.246-251
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• 1998

이동컴퓨터의 기술발전과 더불어 인터넷환경에서 다양한 서비스지원을 위한 이동성지원에 대한 연구가 최근에 활성화되고 있다. 그러나 다자간회의나 다양한 네트워크 환경을 조성하고 있는 인터넷으로 적용을 위해서는 인터레이스를 유연성 있게 지원하는 방법이 제시되어야 한다. IP 기반의 이동컴퓨팅 환경에서는 이동성지원을 위해서 이동호스트의 위치를 정의할 수 있는 Mobile-IP 연구와 멀티캐스트를 지원하는 멀티캐스트연구가 진행되고 있다. 본 논문에서는 IP 기반 이동컴퓨팅 환경에서 멀티캐스트를 지원하기 위한 요구사항을 연구분석하며 인터네트워크 환경으로 적용을 위한 다양한 인터페이스 지원 모델을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.861-864
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• 2006

인터넷과 무선통신 기술의 발달로 Mobile IP 에 대한 관심이 높아지고 있는 가운데 이동 중에도 멀티캐스트 서비스를 이용하기 위해 여러 가지 기술이 연구되고 있다. 인터넷과 멀티캐스트는 열린 모델이라 보안위협에 취약하다. 특히 멀티캐스트에서는 멀티캐스트 분배트리에 대한 접근제어가 중요하다. 본 논문에서는 이동 멀티캐스트에서 멀티캐스트 분배트리에 대한 송신자의 접근제어를 제공하여 서비스의 신뢰성을 높일 수 있는 MSAC (Multicast Source Access Control) 메커니즘을 제안한다. MSAC 과정은 이동하는 멀티캐스트 송신자의 정보들을 MSAC 서버를 통해 인증을 받아 허가되지 않은 노드의 멀티캐스트 분배 트리에 대한 접근을 방지하는 기법이다. MSAC 는 인터넷의 계층적인 특성을 이용하여 인증 회수를 줄이고, 토큰 인증방식을 사용하여 인증 시 메시지를 교환하는 횟수를 줄인다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.322-324
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• 2004

IEEf 802.11 Point Coordination Function (PCF) mode is defined to support time bounded traffic, such as VoIP in wireless LANs. The poll scheduling plays an important role in IEEE 802.11 PCF mode operation. This paper proposed a Multicast Polling Scheme to increase the performance of wireless LANs. Moreover, we proposed a polling schedule scheme for our proposed multipoll to serve real-time traffic. The results show that the proposed mechanism is more efficient than the original IEEE 802.11 PCF.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.498-507
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• 2001

For the Internet multicast routing, there are some protocols researched. This paper presents a new protocol called DPIM (Delay-bounded PIM) to support QoS of delay in multicast routing. This protocol is based on PIM-SM. When the specified delay bound is not satisfied by dynamic membership, the RP (Rendezvous Point) of shared tree is changed and the shared tree is reconstructed. Therefore, the QoS of delay is always supported in this protocol. Through performance analysis and comparison with other protocol, we certify that this protocol is pertinent.