• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.257-260
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• 2001

As today's network infrastructure continues to grow and DiffServ IP networks ate now available to provide various levels of flexible QoS services. DiffServ guarantees good scalability but shows dynamic QoS dependent on network traffic loads. Therefore, in this paper, we investigate the dynamics of DiffSev QoS and present analytical model to estimate the allowable traffic load under the given network conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.697-710
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• 2004

Differentiated services (DiffServ) model has been prevailed as a scalable approach to provide quality of service in the Internet. However, there are difficulties in providing the guaranteed service in terms of end-to-end systems since differentiated services network considers quality of service of aggregated traffic due to the scalability and many researches have been mainly focused on per hop behavior or a single domain behavior. Furthermore quality of service may be time varying according to the network conditions. In this paper, we study dynamic class mapping mechanism to guarantee the end-to-end quality of service for multimedia traffics with the minimum network cost over differentiated services network. The proposed algorithm consists of an effective implementation of relative differentiated service model, quality of service advertising mechanism and dynamic class mapping mechanism. Finally, the experimental results are provided to show the performance of the proposed algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3B
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• pp.175-182
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• 2006

In this paper, we propose a Localized Adaptive QoS Routing Scheme using POMDP and Exploration Bonus Techniques. Also, this paper shows that CEA technique using expectation values can be simply POMDP problem, because performing dynamic programming to solve a POMDP is highly computationally expensive. And we use Exploration Bonus to search detour path better than current path. For this, we proposed the algorithm(SEMA) to search multiple path. Expecially, we evaluate performances of service success rate and average hop count with $\phi$ and k performance parameters, which is defined as exploration count and intervals. As result, we knew that the larger $\phi$, the better detour path search. And increasing n increased the amount of exploration.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.562-564
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• 2002

본 논문에서는 멀티미디어 데이터와 실시간 특성을 가진 데이터의 end-to-end 전달기능과 QoS 감시기능 등을 지원하기 위해 개발된 RTP를 분석하고 개선방안을 제시한다. 기존의 RTP 구현 모듈은 실시간 전달기능은 지원하나, 상세한 QoS 파라미터 보장측면에서는 해결해야할 사항이 존재한다. 따라서 본 논문에서는 이러한 문제점을 해결하기 위해 송신측에서 보낸 데이터에 대한 전송 정보를 수신측으로부터 제공받아, 이를 토대로 네트워크의 상태를 3단계로 분류하여 네트워크에의 QoS를 보장할 수 있는 방안을 제안하고 성능 검증을 수행한다.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.45-54
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• 2002

MPLS(Multiprotocol Label Switching) is regarded as a core technology for migrating to the next generation Internet. In this paper, we propose an dynamic flow admission control supporting DiffServ(Differentiated Services) to provide QoS in MPLS networks. Our proposed model dynamically adjusts the amount of admissible traffic based on transmittable capacity over one outgoing port. It then transmits the Packets while avoiding congested area resulting traffic loss. Ingress LSRs find out the congested area by collecting network state information at QoS state update for QoS routing table. Our Proposed model manages the resource efficiently by protecting the waste of resources that is a critical Problem of DiffServ and makes much more flows enter the network to be served.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.736-745
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• 2009

The growth of mobile devices and the increase of using them have required the support of realtime multimedia application in wireless environments. Especially, wireless ad-hoc networks without central management system and with dynamically changing network topology need much researches of QoS routing for multimedia applications. However it is impossible to support the hard realtime QoS for these dynamic networks. In this paper, we propose a QoS routing scheme by using QoS DAG that is maintained by each mobile node and contains the QoS information for neighbor nodes. In order to maintain the QoS DAG, each node transmits its QoS information to neighbor nodes by local broadcasting, and the neighbor nodes update their QoS DAGs by the received message. In our proposed scheme, it is possible to search the QoS path efficiently by the QoS DAG without searching it in the whole network.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.156-166
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• 2005

Ethernet passive optical network is an economical and efficient access network that has received significant research attention in recent years. A MAC(Media Access Control) protocol of PON, the next generation access network, is based on TDMA(Time Division Multiple Access) basically. In this thesis, we addressed the problem of dynamic bandwidth allocation in QoS based Ethernet PONs. We augmented the bandwidth allocation to support QoS in a differentiated services framework. Our differentiated bandwidth guarantee allocation(DBGA) allocates effectively and fairly bandwidths among end users. Moreover, we showed that DBGA that perform weighted bandwidth allocation for high priority packets result in better performance in terms of average and maximum packet delay, as well as network throughput compared with existing dynamic bandwidth allocations. We used simulation experiments to study the performance and validate the effectiveness of the proposed bandwidth allocations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.192-201
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• 2005

DiffServ supports aggregated traffic classes to provide various QoS to different classes of traffics. However, current DiffServ specifications do not have a complete QoS management framework. It is possible to lead to serious QoS violations without a QoS management support. From this reasoning, a QoS management system that can manage differentiated QoS provisioning is required. This paper proposes and implements a policy-based QoS management platform for differentiated services networks, which specifies QoS policies to guarantee dynamic QoS requirements. The implementation of the proposed platform is built on W framework and uses XML to represent and validate high-level QoS policies. High-level QoS policies are represented as valid XML documents and are mapped into Em beans of the EJB-based policy server of the platform. The policy distribution and the QoS monitoring are processed using SNMP.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.691-693
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• 1999

이동 컴퓨팅 환경은 유선망에 비하여 대역폭이 낮고, 호스트의 성능이 낮으며, 사용자의 이동에 따른 여러 가지 문제점이 나타난다. 이러한 이동 컴퓨팅 환경에서 멀티미디어 서비스를 제공하기 위해서는 무엇보다 QoS 제어가 중요하다. 따라서 본 논문에서는 이동 멀티미디어 컴퓨팅 환경의 동적 변화에 적응하고, 효율적으로 QoS를 제어하기 위하여 동적 우선순위를 기반으로 한 QoS 제어 기법을 제시한다. 동적 우선순위는 최초 연결성정 시에 결정되는 정적 우선순위와 보상을 기반으로 한 대역폭 변화값에 따라 결정되며, QoS 제어를 위한 기준으로 사용된다. 이러한 동적 우선순위는 낮은 QoS를 제공받은 MH(Mobile Host)가 핸드오프를 수행하여 새로운 셀로 이동한 경우에도 지속적으로 낮은 QoS를 제공받는 문제를 해결함으로써 공평하게 대역폭을 할당하는 장점이 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.488-490
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• 2012

Nowadays QoS / QoE using technology as part of HTTP, dynamic adaptive streaming technology that became a big issue. In this paper, using HTTP, dynamic adaptive streaming technology is introduced. This dynamic adaptive streaming using HTTP-based system design and implementation. In this system, a number of MPEG2-TS file bitrate's conversion of image quality, a certain amount of time by the division of Segment, standing before the final note of the files that are used in transmission MPD (Media Presentation Description) File creation and streaming between servers and clients using HTTP to a dynamic and adaptive network environment consists of bitrate's streamers. In a network environment in which an unspecified number of seamless continuous playback of video streaming for a variety of sectors and will be utilized in the field of multimedia.