• 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.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.383-389
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• 2003

In this paper, we propose a solution, called M_DQDMR, for generating delay-constrained boundwidth-appropriated multicast routing trees to reduce the delay and conserved boundwidth resources of nodes in mobile computing environment. At the current router installation, we according the routing table and the information of link which neighboring rude to guarantee QoS(Quality of Service). When we construct multicast tree, M_DQDMR algorithm dynamically adjusts its appropriate tree construction policy based on how far the destination node from the delay bound and boundwidth our QoS requirement. Through simulations and comparing to another multicast algorithm, we reach a conclusion is that M_DQDMR can simply and dynamically adjusts the construction of multicast tree in hight-speed and conserve boundwidth resources.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.491-497
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• 2012

Network coding is that the nodes can combine and mix the packets rather than merely forward them. Therefore, network coding is expected to improve throughput and channel efficiency in the wireless network. Relevant researches have been carried out to adapt network coding to wireless multi-hop network. In this paper, we designed the network coding for bidirectional traffic service in routing layer and IP layer of Ad-hoc network. From the simulation result, the traffic load and the end to end distance effect the performance of the network coding. As end to end distance and the traffic load become larger, the gain of network coding become more increased.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1189-1192
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• 2003

초기 콜 센터는 단순히 고객에게 걸려오는 전화를 응대하는 서비스 수준으로 시작되었지만, 현재는 고객과 마주하는 최 접점으로 서비스 뿐만 아니라 마켓팅, 세일즈를 행하는 기업의 경쟁력을 유지하는데 있어 필수적인 요소로 자리잡아 가고 있다. 특히 개인고객을 많이 접하는 금융기관에서는 콜 센터를 대형화, 지방 분산화 및 백업체제 구축을 위한 Multi 센터를 구축하여 콜만 처리하는 센터로서가 아니라 다양한 채널[전화,email,fax,chating]를 통해 접속되는 고객요구 사항들을 통합된 인프라에서 One Stop 으로 처리하고자 한다. 하지만 회선 교환망을 이용하는 PBX기반 Voice 회선과 IP 환경의 DATA 를 처리하는 이원화된 구조로 Multi 콜 센터를 구축 할 경우, 타 센터의 상담원에게로 콜을 설정시 시간이 많이 소요되어 센터간 Call Load Balancing 및 상담원 Skill Based Routing 을 수행함이 어렵다는 단점이 있다. 본 논문에서는 이러한 단점을 개선할 수 있는 방안으로 Voice 와 Data 를 IP 기반 단일 망으로 구성하고 WAN상에서 음성을 전달할 때 적정한 MOS(Mean opinion score)를 측정 후 객관적으로 필요한 Bandwidth 를 검증하고 Muti 콜 센터에서 효과적인 콜 load Balancing 및 Routing을 할 수 있는 VOIP기반 Convereed Virtual Call Center Architecture 설계 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.160-161
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• 2013

Extending mobile IP to ad hoc networks with the foreign agent acting as the bridge between the wired network and ad hoc networks can provide the global Internet connectivity for ad hoc hosts. The existing research in the area of the integrated wired and ad hoc network is carried out in a non-adversarial setting. This paper analysed an effective solution to solve the security related problems encountered in these integrated networks. This security protocol also excludes malicious nodes from performing the ad hoc network routing. This paper focuses on preventing ad hoc hosts from the attacks of anti-integrity.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.34-41
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• 2008

Existing mobility support scheme like MIPv4 has the delay at data transfer and Triangle routing problem. This paper proposes the new mobility support scheme and method that can overcome the problem using MPLS LSP in Next Generation Network. The proposed scheme overcomes the problem by introducing the LMS(Location Management Server) managing the location of the mobile terminal and the MPLS LSP between FA for a tunneling. We shows on the mathematical analysis using the queuing theory that this proposed scheme is more superior to the existing method(MIP).

• Journal of Communications and Networks
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• v.11 no.3
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• pp.297-305
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• 2009

Multiprotocol label switching (MPLS) networks require dynamic flow admission control to guarantee end-to-end quality of service (QoS) for each Internet protocol (IP) traffic flow. In this paper, we propose to tackle the joint routing and admission control problem for the IP traffic flows in MPLS networks without rerouting already admitted flows. We propose two mathematical programming models for this problem. The first model includes end-to-end delay constraints and the second one, end-to-end packet loss constraints. These end-to-end QoS constraints are imposed not only for the new traffic flow, but also for all already admitted flows in the network. The objective function of both models is to minimize the end-to-end delay for the new flow. Numerical results show that considering end-to-end delay (or packet loss) constraints for all flows has a small impact on the flow blocking rate. Moreover, we reduces significantly the mean end-to-end delay (or the mean packet loss rate) and the proposed approach is able to make its decision within 250 msec.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2764-2771
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• 1999

ATM has recently received much attention because of its high capacity, its bandwidth scalability, and its ability to support multiservice traffic. However, ATM is connection oriented whereas the vast majority of modern data networking protocols are connectionless. The alternative to support current service on ATM will be a router with attached switching hardware that has the ability to cache routing decisions. In this paper, we described the router using a switch and simulated the performance. From the results of the simulation, the routing delay was decreased as the number of flow channels. Cell-delay was shortest at 30,000 cell-time when the keeping time of a flow channel was. The line utilization was rapidly decrease when a flow-setup time is 20 30 cell-time. The results of this simulation could be applied to predict the performance of the router using ATM switch.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.889-892
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• 2008

최근 이동 중에도 인터넷을 사용하고자하는 사용자의 요구에 맞추어 노드의 이동성을 제공하기 위한 기술들이 개발되고 있다. 그 중 대표적인 기술이 네트워크 계층에서의 이동성 관리 기법인 Mobile IP 기술이다. Mobile IP 기술은 크게 두 가지 분류로 나눌 수 있다. 하나는 호스트가 직접 핸드오프에 대한 시그널링을 수행하는 호스트 기반 이동성 관리 기술이고, 다른 하나는 네트워크 엔터티가 호스트를 대신하여 호스트의 이동에 따른 시그널링을 수행하는 네트워크 기반 이동성 관리 기술이다. 전자의 대표적인 프로토콜은 Mobile IPv6, Fast Mobile IPv6, Hierarchical Mobile IPv6가 있고, 후자의 대표적인 프로토콜은 Proxy Mobile IPv6 기법이 있다. 그 중, 최근 가장 주목 받고 있는 기술은 Proxy Mobile IPv6이다. 네트워크 기반 이동성 관리라는 개념이 서비스 제공자와 기기 제조사에게 모두 이득을 주는 방식이기 때문이다. 하지만 Proxy Mobile IPv6는 아직 개발 중인 기법이라 최적화에 대한 논의가 끝나지 않았다. 특히 Proxy Mobile IPv6 도메인 내에서의 라우팅 최적화에 대한 논의는 활발하게 이루어지고 있다. 본 논문에서는 Proxy Mobile IPv6의 네트워크 엔터티인 Mobile Access Gateway의 라우팅 테이블을 이용한 라우팅 최적화 기법을 제안한다. 또한 제안한 기법이 가져오는 성능향상과 효과에 대해 분석한다.

• Journal of KIISE:Information Networking
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• v.36 no.1
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• pp.57-67
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• 2009

Packet forwarding in the Internet routers is to find out the longest prefix that matches the destination address of an input packet and to forward the input packet to the output port designated by the longest matched prefix. The IP address lookup is the key of the packet forwarding, and it is required to have efficient data structures and search algorithms to provide the high-speed lookup performance. In this paper, an efficient IP address lookup algorithm using binary search is investigated. Most of the existing binary search algorithms are not efficient in search performance since they do not provide a balanced search. The proposed binary search algorithm performs perfectly balanced binary search using switch pointers. The performance of the proposed algorithm is evaluated using actual backbone routing data and it is shown that the proposed algorithm provides very good search performance without increasing the memory amount storing the forwarding table. The proposed algorithm also provides very good scalability since it can be easily extended for multi-way search and for large forwarding tables