• Journal of Digital Contents Society
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• v.12 no.4
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• pp.485-490
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• 2011

Smoothing is a transmission plan where variable rate video data is converted to a constant bit rate stream. These smoothing algorithms include CBA, MCBA, MVBA, PCRTT and others. But, these algorithms build a transmission plan per frame unit. So, these algorithms cause frame burst or GOP burst. In order to improve it, MVBAG algorithm build a transmission plan per GOP. But this algorithm may not guarantee QoS when frame's size is abruptly larger or smaller than the computed transmission rate. In this paper, a smoothing algorithm is proposed to enhance MVBAG algorithm's problem. In order to show the proposed algorithm's performance, the proposed algorithm is compared with MVBAG algorithm using various evaluation factors such as number of frames that do not meet the QoS, average transmission rate variability per frame, average transmission rate variability per GOP. Experimental results show that the proposed algorithm outperforms MVBAG algorithm in number of frames that do not meet the QoS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.585-597
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• 2004

In this paper, we propose the functional models of optical burst switching (OBS) routers to apply GMPLS (Generalized Multiprotocol Label Switching) to optical networks based on OBS. In addition, we introduce a connection admission control (CAC) algorithms which are operated in this models and can accommodate the required QoS. Firstly, the characteristics of current GMPLS and OBS for the optical Internet are basically considered. With this consideration, the models are proposed to accept OBS features which include the recognition of data boundary with control information and the statistical multiplexing in terms of bursts. Secondly, we use an offset time decision (OTD) algorithm on behalf of controlling the connection admission with taking QoS parameters such as burst loss rate(BLR) and service-differentiation ratio(SDR) into consideration. The proposed CAC algorithms use the offered load of LSP (Label Switched Path), wavelength information, and QoS parameters as inputs of OTD algorithm. A call setup request will be accepted when the offset time decided by OTD algorithm is reasonable for guaranteeing its requested QoS. Simulation is used for performance evaluation. Results show the proposed schemes can guarantee the required QoS and those are better than the previous one in terms of channel utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.778-790
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• 2004

In this paper, we propose the functional models of optical burst switching (OBS) routers to apply GMPLS (Generalized Multiprotocol Label Switching) to optical networks based on OBS. In addition, we introduce a connection admission control (CAC) algorithms which are operated in this models and can accommodate the required QoS. Firstly, the characteristics of current GMPLS and OBS for the optical Internet are basically considered. With this consideration, the models are proposed to accept OBS features which include the recognition of data bounda η with control information and the statistical multiplexing in terms of bursts. Secondly, we use an offset time decision (OTD) algorithm on behalf of controlling the connection admission with taking QoS parameters such as burst loss rate(BLR) and service-differentiation ratio(SDR) into consideration. The proposed CAC algorithms use the offered load of LSP (Label Switched Path), wavelength information, and QoS parame ‘ ers as inputs of OTD algorithm. A call setup request will be accepted when the offset time decided by OTD algorithm is reasonable for guaranteeing its requested QoS. Simulation is used for performance evaluation Results show the proposed schemes can guarantee the required QoS and those are better than the previous one in terms of channel utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1517-1531
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• 1999

The Internet is recently evolving into the directions which is capable of incorporating stream-type services such as voice and video services. However, the existing Internet can only support a best-effort delivery model and thus it is difficult to satisfy these requirements as well as to provide the QoS beyond a certain degree. Accordingly, it is imperative to develop QoS based routing algorithm in order to allow the routing by the user's QoS demand and to be applied into wide area networks. In this thesis, we presented new routing algorithms and made performance evaluations. The proposed algorithms allow the routing by the user’s QoS demand level in order to provide the diverse Internet application services based on ATM network environment that is expected to play a role as an infrastructure of high-speed communication network. They also have a feature of shortening the waiting time for address analysis and have a quality-proven characteristics with enhanced network scalability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.820-822
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• 2010

Mobile WiMAX system provides various classes of traffic such as real-time and non-realtime services. These services have different QoS requirements and the QoS aware scheduling has been an important issue. Although many of scheduling algorithms for various services in OFDMA system have been proposed, it is needed to be modified to be applied to Mobile WiMAX system. Since Mobile WiMAX supports five kinds of service classes, it is important to take QoS characteristics of each class into consideration. In this paper, we propose an efficient packet scheduling algorithm to support QoS of each class. Proposed scheme selects a service class first considering QoS Characteristics of each class and choose an appropriate user in the selected class. Simulation results show that the proposed algorithm has better performance than the other algorithm.

• Journal of the Korea Society of Computer and Information
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• v.21 no.4
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• pp.17-24
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• 2016

In this paper, we propose a AH LSU(Advanced Hybrid QoS Routing Link State Update) Algorithm that improves the performance of Hybrid LSU(Hybrid QoS Link State State Update) Algorithm with statistical information of flow holding time in network. AH LSU algorithm has had both advantages of LSU message control in periodic QoS routing LSU algorithm and QoS routing performance in adaptive LSU algorithm. It has the mechanism that calculate LSU message transmission priority using the flow of statistical request bandwidth and available bandwidth and include MLMR(Meaningless LSU Message Removal) mechanism. MLMR mechanism can remove the meaningless LSU message generating repeatedly in short time. We have evaluated the performance of the MLMR mechanism, the proposed algorithm and the existing algorithms on MCI simulation network. We use the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.378-380
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• 1999

무선 네트워크 환경에서는 제한된 네트워크의 대역폭과 모바일 호스트의 잦은 이동성으로 인하여 다양한 종류의 트래픽(Traffic)에 대한 Quality of Service(QoS)를 보장하는 것이 어렵다. 이러한 특징을 가지는 무선 네트워크 환경에서도 특정 종류의 트래픽(예를 들어 실시간 트래픽)에 대하여 요구된 범위내에서의 QoS가 반드시 보장되어야 한다. 본 논문에서는 이동성을 제공하는 무선 네트워크 환경에서 다양한 종류의 실시간 트래픽에 대해 QOS를 보장하는 어댑티브 레이트 얼로케이션 알고리즘을 제안한다. 제안된 레이트 얼로케이션 알고리즘은 이동성에 따라 변화하는 네트워크 자원 환경을 고려하여 각 트래픽의 QoS를 최대한 보장하는 방향으로 레이트 (Rate)를 조절한다.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.324-333
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• 2001

The Differentiated Services (Diffserv) framework has been proposed by the IETF as a simple service structure that can provide different Quality of Service (QoS) to different classes of packets in IP networks. IP packets are classified into one of a limited number of service classes, and are marked in the packet header for easy classification and differentiated treatments when transferred within a Diffserv domain. The Diffserv framework defines simple and efficient QoS differentiation mechanisms for the Internet. However, the original Diffserv concept does not provide a complete QoS management framework. Since traffic flows in IP networks are unidirectional from one network point to the other and routing paths and traffic demand get dynamically altered, it is important to monitor end-to-end traffic status, as well as traffic status in a single node. This paper suggests a distributed QoS monitoring method that collects the statistical data of each service class in every Diffserv router and calculates edge-to-edge QoS of the aggregated IP flows by combining routing topology and traffic status. A format modeling of edge-to-edge Diffserv flows and algorithms for aggregating edge-to-edge QoS is presented. Also an SNMP-based QoS management prototype system for Diffserv networks is presented, which validates our QoS management framework and demonstrates useful service management functionality.

• Journal of Communications and Networks
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• v.12 no.1
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• pp.86-94
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• 2010

In this paper, we present a decentralized algorithm to find minimum cost quality of service (QoS) flow subgraphs in network coded multicast schemes. The main objective is to find minimum cost subgraphs that also satisfy user-specified QoS constraints, specifically with respect to rate and delay demands. We consider networks with multiple multicast sessions. Although earlier network coding algorithms in this area have demonstrated performance improvements in terms of QoS parameters, the proposed QoS network coding approach provides a framework that guarantees QoS constraints are actually met over the network.

• 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.