• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.608-619
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• 2004

Application layer multicast(ALM) has been developed as an alternative to support the multi-receiver applications due to the slow deployment of IP multicast. Unlike routers in IP multicast, end systems participating in a ALM session are not optimized for relaying data and have various processing and network capacity. Therefore, with the increased role of end systems, the delay incurred at the end systems occupy large portion of the end-to-end delay. In this paper, we model the end system delay of ALM sessions and analyze its impact on the performance of the existing ALM schemes. Furthermore, we propose an enhanced scheme, based on the existing mesh-based scheme, which reflects the end system delay We also evaluate the performance of the proposed scheme by simulation and show that it reduces the end-to-end delay compared with the existing scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.630-638
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• 2005

As real-time media applications based on IP multicast networks spread widely, the end-to-end QoS (quality of service) provisioning for these applications have become very important. To guarantee the end-to-end QoS of multi-party media applications, it is essential to monitor the time-varying status of both network metrics (i.e., delay, jitter and loss) and system metrics (i.e., CPU and memory utilization). In this paper, targeting the multicast-enabled AG (Access Grid) group collaboration tool based on multi-Party real-time media services, a hybrid monitoring scheme that can monitor the status of both multicast network and node system is investigated. It combines active monitoring and passive monitoring approaches to measure multicast network. The active monitoring measures network-layer metrics (i.e., network condition) with probe packets while the passive monitoring checks application-layer metrics (i.e., user traffic condition by analyzing RTCP packets). In addition, it measures node system metrics from system API. By comparing these hybrid results, we attempt to pinpoint the causes of performance degradation and explore corresponding reactions to improve the end-to-end performance. The experimental results show that the proposed hybrid monitoring can provide useful information to coordinate the performance improvement of multi-party real-time media applications.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.143-148
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• 2005

Video conference system it is various at internet and uses the reading is become accomplished. Research of like this portion synchronization of audio, the compression technique and multimedia data, supports the video conference the research of the Mbone of the IP multicast for being active. being become accomplished the multimedia service which is various an video from internet, the line speed of communication becomes high-speed anger and to follow leads is become accomplished. The video conference from opening elder brother dispersion internet network environment the problem against the image which is an image conference data and a voice security is serious and it raises its head. To sleep it presents the security method which from the video conference it follows in quality of multimedia data from the dissertation which it sees and it does.

• ETRI Journal
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• v.27 no.1
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• pp.13-21
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• 2005

Many multicast applications, such as video-on-demand and video conferencing, desire quality of service (QoS) support from an underlying network. The differentiated services (DiffServ) approach will bring benefits for theses applications. However, difficulties arise while integrating native IP multicasting with DiffServ, such as multicast group states in the core routers and a heterogeneous QoS requirement within the same multicast group. In addition, a missing per-flow reservation in DiffServ and a dynamic join/leave in the group introduce heavier and uncontrollable traffic in a network. In this paper, we propose a distributed and stateless admission control in the edge routers. We also use a mobile agents-based approach for dynamic resource availability checking. In this approach, mobile agents act in a parallel and distributed fashion and cooperate with each other in order to construct the multicast tree satisfying the QoS requirements.

• 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 Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1303-1309
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• 2012

In this paper, we propose a handover scheme for seamless mobile multicast service in next generation access networks. For this, we drew optimum handover scheme when applying MIP(mobile IP), FMIP(Fast MIP), HMIP(Heterogeneous MIP), PMIP(Proxy MIP) to XG-PON1. And, we analyze handover scheme for seamless mobile multicast service in XG-PON1. The prosed handover scheme remove tunnel convergence and reduces handover delay, packet delivery cost.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.620-632
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• 2004

IP is not suitable for mobile nodes by network-based routing because mobile nodes are dynamically change their network attachment point. Mobile-IP is an IETF standard providing continuous access to the Internet for mobile nodes, but it has the triangle routing problem. Also it has a performance degradation problem by massive packet loss during layer 3 handoff of mobile nodes. Especially, two IETF multicast support schemes for Mobile-IP do not guarantee the quality of realtime multimedia services because they have several problems such as long routing path, packet duplication(hi-directional tunneling) and massive packet loss(remote subscription). In this paper, we propose a lossless remote subscription scheme that guarantees the quality of realtime multimedia services over Mobile-IP. From the result of simulation, we verified that the proposed scheme in this paper can reduce the delay time of remote subscription by the effect of the low latency handoff scheme that is extended to apply to the multicast group management and it requires only 0.58% buffer spaces of the previously proposed lossless remote subscription scheme.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.445-447
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• 1999

이동호스트를 지원하는 이동네트웍에서의 멀티캐스팅 문제는 빈번한 그룹 멤버쉽의 변화와 함께 그룹 멤버의 위치 변화를 가져와 기존의 고정 호스트를 기본으로 설계된 멀티캐스트 프로토콜을 적용하는 것은 적합하지 못하다. 이런 점에서 특히 Mobile IP를 기본 유니캐스팅 방법으로 사용하는 환경에서 이동호스트를 위한 몇가지 멀티캐스팅 방식이 제시되었으나, 비최적 경로의 데이터 전송, 비효율적인 데이터 중복 전송 또는 빈번한 멀티캐스트 트리의 재구성으로 인한 오버헤드 등의 문제점을 내포하고 있다. 따라서 본 논문에서는 이런 문제점을 좀 더 보완하면서 Mobile IP를 사용하는 이동호스트에게 IP 멀티캐스트를 제공하는 효과적인 프로토콜을 제안한다. 호스트의 이동성을 적극 반영하여 유동적으로 멀티캐스트 포워더(Multicast Forwarder)를 선정함으로서 데이터 전송 경로의 단축, 중복되는 데이터 전송의 감소와 같은 효과를 얻을 수 있고 그 결과를 시뮬레이션을 통하여 확인해 본다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.262-264
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• 2001

컴퓨터 네트웍 시스템에서 부각되고 있는 두 가지 중요한 추세는 아마도 ‘멀티미디어’와 ‘이동 컴퓨팅’일 것이다. 멀티캐스트는 멀티미디어 데이터가 차지하는 많은 네트웍 트래픽을 수신 컴퓨터들에게 효율적으로 분배함으로써 네트웍 트래픽을 줄일 수 있다. 그러나 이동 호스트를 지원하는 이동 네트웍에서의 멀티캐스팅은 빈번한 그룹 멤버쉽의 변화와 함께 그룹 멤버의 위치변화로 인해서 기존의 고정 호스트를 기본으로 설계된 멀티캐스트 프로토콜을 적용하는 것은 적합하지 못한다. 이런 점에서 Mobile IP를 기본 유니캐스팅 환경에서 채택하여 이동 호스트에게 멀티캐스트를 지원하기 위한 몇 가지 방법이 제시되었으나, 비최적 경로로의 데이터 전송, 비효율적인 데이터 중복 전송, 또는 빈번한 멀티캐스트 트리의 재구성으로 인한 오버헤드 등의 문제점을 내포하고 있다. 제안된 프로토콜에서는 이동 호스트에게 멀티캐스트 서비스를 제공하는 FMA(Foreign Multicast Agent)를 유동적으로 선정하고 이동 호스트가 가지는 타임아웃 값을 이용하여 이동성으로 인해 발생하는 문제점들을 완화시킴으로써, Mobile IP를 이용하는 이동 호스트에게 IP멀티캐스팅을 효과적으로 제공한다.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.33-43
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• 2011

Routing technologies considering QoS-based hypermedia services have been seen as a crucial network property in next generation optical Internet (NGOI) networks based on IP/dense-wavelength division multiplexing (DWDM). The huge potential capacity of one single fiber. which is in Tb/s range, can be exploited by applying DWDM technology which transfers multiple data streams (classified and aggregated IP traffics) on multiple wavelengths (classified with QoS-based) simultaneously. So, DWDM-based optical networks have been a favorable approach for the next generation optical backbone networks. Finding a qualified path meeting the multiple constraints is a multi-constraint optimization problem, which has been proven to be NP-complete and cannot be solved by a simple algorithm. The majority of previous works in DWDM networks has viewed heuristic QoS routing algorithms (as an extension of the current Internet routing paradigm) which are very complex and cause the operational and implementation overheads. This aspect will be more pronounced when the network is unstable or when the size of network is large. In this paper, we propose a flooding-based unicast and multicast QoS routing methodologies(YS-QUR and YS-QMR) which incur much lower message overhead yet yields a good connection establishment success rate. The simulation results demonstrate that the YS-QUR and YS-QMR algorithms are superior to the previous routing algorithms.