• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.512-517
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• 2006

차세대 통신망은 IP 기반 핵심망을 중심으로 무선 액세스망을 비롯한 다양한 액세스망들이 접속되는 형태가 될 것으로 전망되고 있다. 이러한 망 환경에서 사용자가 만족할 수 있는 수준까지 멀티미디어 서비스를 제공하기 위해서는 서비스품질(QoS)이 필수적으로 보장되어야 한다. 특히, 종단간(end-to-end) QoS가 보장되어야 하는데, 이러한 종단간 QoS를 보장하기 위해서는 네트워크 QoS 뿐만 아니라 애플리케이션 계층에서의 QoS도 함께 지원되어야 한다. 본 논문에서는 네트워크에서 혼잡현상이 발생할 경우, 종단간 QoS를 제공하기 위해 송신측에서 가변 멀티코덱(애플리케이션 계층)을 사용하여 트래픽손실 및 지연을 줄일 수 있는 방법을 제안하고, 시뮬레이션을 이용한 성능 분석결과를 제시함으로써 제안된 방식의 타당성을 보인다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2798-2805
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• 1997

The paper studies the Quality of Service(QoS) concept in Broadband Integrated Services Digital Network (B-ISDN). Guaranteeing the QoS requirements indistributed multimedia systems and networks is fundamentally an end-to-end issus, that is, from application to application. An important issue in the QoS translation between the application-level QoS and network-level QoS is that the translation depends not only on the translation between system resources and network resources, but also on the translation between thelayered protocol and the access procedures. In this paepr, we propose a methodology for translating the AAL(ATM Adaptation Layer) QoS parameters into the ATM layer QoS parameters in end-systems. The QoS parameters in the ATM layer and AAL are defined, and we concentrate on the translation from the AAL to the ATM layer, because the AAL must be designed to be service dependent and specific. As an example, we concentrate on the constant bit rate(CBR) guaranteed real-time service using AAL1 protocol.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.74-84
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• 2001

In the current Internet, InteServ model based on Resource reSerVation Protocol (RSVP), DiffServ Model based on service differentiation according to per hope behavior(PHB) and traffic engineering policy, and two-tire model of above mentioned two models which are adapted differently as the target network status for providing the end-to-end QoS Path are suggested. But, when we integrated this internet QoS into the ATM based network, differences of the connection setup procedure, name/address translation methods, and QoS provisioning mechanisms for end-to-end path setup procedures are introduced. In this paper, we propose the method of shortcut based QoS path setup procedure to solve these problems, and to guarantee the integration and scalability of Next Generation Internet(NGI) names/address in Integrated IP network into ATM based network. This network should support the engineering differentiated into the multiple service classes, which depend on established by this path is designed suitably into the target router and host step by step. In the near future, this function which provide the QoS guaranteed path based on end-to-end shortcut between the configuration devices are extended into the NGI target network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2A
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• pp.196-201
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• 2010

Measurement of Quality of Service (QoS) parameters and its statistical analysis becomes a key issue for Mobile WiMAX service providers to manage the converged network efficiently and to support end-to-end QoS. In this paper, we investigate the population distribution of end-to-end one-way delay which is the most important QoS parameter in Mobile WiMAX networks. The samples are analyzed with Chi-Square Goodness-of-Fit test, Kolmogorov-Smirnov (K-S), and Anderson-Darling (A-D) test to verify the distribution of parent population. The relation with confidence level and the minimum number of sample size is also performed for logistic distribution. The statistical analysis is a promising approach for measuring the performance Mobile WiMAX networks.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.562-565
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• 2009

이종 망 환경에서 멀티미디어 서비스의 QoS를 보장하는 것은 3GE 시스템 개발을 위한 중요한 이슈이다. 이동 단말기가 이종 망간의 이동 시 끊임없는 서비스(seamless service)를 지원하기 위해서는 종단간(end-to-end) 협상 정보에 근거하여 사용자의 QoS를 보장할 수 있는 QoS 운영 구조(QoS management structure)를 제공해야 한다. 본 논문에서는 SLA(Service Level Agreement)에 기반한 종단간 QoS 제어 방안을 제시한다. 이를 위하여, QoS 지원을 위한 SLA 제어 구조 및 알고리즘을 제안하고, 시뮬레이션을 통하여 평균 지연과 패킷 손실률을 평가한다. 제안된 방식을 적용한 시스템이 기존의 망보다 더 좋은 성능을 보인다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3309-3319
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• 1999

Seamless end-to-end Internet Quality of Service (QoS) management is very only because Internet Management is not well understood and practiced in the real world but because the nature of the Internet is hard to predict and manage. Secure transmission, transport reliability, ability to differentiate service qualities, QoS-based intelligent routing, QoS monitoring, and customer-oriented service management are essential technical huddles to be coped with. Despite of these difficulties, the Internet becomes the platform of choice for the next generation applications and services. without a solid management solution, it is not easy to deploy high quality commercial services. In this paper, we propose an architecture of seamless end-to-end Internet QoS Management System and describe the design principles and system components of our developing prototype system.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.469-472
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• 2000

인터넷 사용자의 급속한 증가와 전자 상거래의 발전은 다양한 시스템 및 네트워크의 설계 및 관리를 매우 복잡하게 변화시켰다. 본 연구에서는 인터넷/ 인트라넷과 같은 분산 망에서의 서비스 보장을 위해 종단 시스템(End-to-End System)에서의 QoS(Quality of Service) 지원과 QoS 제어 메커니즘을 분석하여 분산 망에서의 종단 사용자(End-User)를 위한 QoS 정책 관리 구조를 제안하였다. 이 구조는 종단 호스트 모델과 네트워크 모델의 통합 지원 구조로 구성되며, 각 모델의 해당 자원에 대한 서비스를 구분하여 사용자 정책을 관리하며, 분산 망에 대해서는 단위 네트워크의 QoS 관리 서버를 통하여 종단 시스템간의 QoS 정책을 관리하게 된다. 본 논문에서 제안한 구조는 분산 망에서의 종단 사용자 정책을 관리하는데 있어 응용 서비스 고유의 특성을 보장하며 사용자 정책에 따른 서비스 자원을 통합 관리할 수 있다.

• The KIPS Transactions:PartC
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• v.16C no.3
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• pp.363-372
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• 2009

For large scale VOD service, cluster servers are spotlighted to their high performance and low cost. A cluster server usually consists of a front-end node and multiple back-end nodes. Though increasing the number of back-end nodes can result in the more QoS streams for clients, the possibility of failures in back-end nodes is proportionally increased. The failure causes not only the stop of all streaming service but also the loss of the current playing positions. In this paper, when a back-end node becomes a failed state, the recovery mechanisms are studied to support the unceasing streaming service. For the actual VOD service environment, we implement a cluster-based VOD servers composed of general PCs and adopt the parallel processing for MPEG movies. From the implemented VOD server, a video block recovery mechanism is designed on parity algorithms. However, without considering the architecture of cluster-based VOD server, the application of the basic technique causes the performance bottleneck of the internal network for recovery and also results in the inefficiency CPU usage of back-end nodes. To address these problems, we propose a new failure recovery mechanism based on the pipeline computing concept.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1211-1214
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• 2005

서비스품질(QoS) 보장은 지속적인 망 자원을 필요로 하는 멀티미디어 응용을 지원하는데 있어 필수적인 사항이다. 무선 환경에서도 멀티미디어의 응용들이 많이 수용될 것으로 전망됨에 따라 무선 환경에서의 QoS 지원에 대한 중요성이 증가되고 있으나, QoS 지원방안이 개별적인 망 단위로 연구되는 경우가 많다. 따라서, 이종 망들이 혼재하는 환경에서, End-to-End QoS 를 보장하기 위한 QoS 연동에 대한 연구가 필요하다. 본 논문에서는 IEEE 802.11 WLAN 과 UMTS 간의 QoS 연동을 지원하기 위해 상이한 QoS 클래스 및 파라미터들 간의 맵핑 방안을 제시하고 시뮬레이션을 통해 End-to-End QoS 가 지원됨을 입증한다.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.85-91
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• 2007

The satellite networks provide global coverage. The integration of terrestrial networks with a satellite network is the most attractive approach to develop a global communication system. The IP Multimedia Subsystem (IMS) is intended to be the system that will merge the internet with the telecom world. A user with a dual-mode terminal can access both the satellite network and terrestrial network. The seamless handoff between two networks and a user's QoS level is the major issue concerning this integration. In this paper, we propose IMS-based satellite/terrestrial integrated network architecture for a global communication system. Based on the proposed architecture, an inter-network handoff and end-to-end soft QoS procedure is discussed. Our proposed soft QoS scheme is also analyzed to calculate the number of rejected calls.