• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.200-200
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• 2006

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.550-555
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• 2001

최근 Internet의 가장 보편적이고 저렴한 Backbone Network 기술이다. 이러한 Internet의 전달 능력은 그대로 이용하면서 보안이 우수한 가상 사설망(VPN)을 구축하는 기술에 대한 수요가 증가하고 있다. 본 논문에서는 MPLS 기반의 터널링을 이용한 VPN망 구축 방안과 광 경로(Lightpath)를 갖는 Optical VPN에서 고려해야할 사항에 대해 제시하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1668-1676
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• 1997

The wireless communication network is evolving toward the Personal Communication System to provide various multimedia services. In order to accomplish this goal, the effective schemes are required which can dynamically utilize the limited wireless resources based on traffic characteristics of each services. This paper proposes a novel call admission control scheme for the hierarchical macrocell/microcell structured PCS. It is based on the bandwidth reservation procedure performed in the macrocell or neighboring microcell. Its effectiveness is investigated by simulation.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1464-1474
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• 2012

In this paper, we propose a QoS (Quality of Service)-aware and cooperative resource reservation scheme using cross-layer link adaptation for wireless high definition video transmission through UWB (Ultra Wide Band) network with D-MAC (Distributed Medium Access Control). A wireless high definition video transmission system usually requires stable high throughput even without line-of-sight, e.g., a destination device in another room separated by a wall. Since the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme causes lots of DRP resource reservation conflicts due to failure of beacon detection in wireless channel environment, overall performances of the WiMedia D-MAC can be deteriorated. And the current WiMedia MAC standard has not considered QoS provisioning even though QoS parameters such as a range of service rates are provided to each traffic stream. Therefore, we propose Relay DRP protocol with QoS-based relay node selection criterion, which makes a relay path to avoid DRP resource reservation conflicts and guarantee QoS more stably through cross-layer link adaptation of cooperative relay transmission scheme and is compliant with the current WiMedia D-MAC protocol. Simulation results demonstrate performance improvements of the proposed method for throughput and QoS provisioning.

• ETRI Journal
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• v.35 no.1
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• pp.7-17
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• 2013

The ongoing proliferation of new services, applications, and contents is leading the Internet to an architectural crisis owing to its inability to provide efficient solutions to new requirements. Clean-slate architectures for the future Internet offer a new approach to tackle current and future challenges. This proposal introduces a novel clean-slate architecture in which the TCP/IP protocol stack is decoupled in basic functionalities, that is, atomic services (ASs). A negotiation protocol, which enables context-aware service discovery for providing adapted communications, is also specified. Then, we present how ASs can be discovered and composed according to requesters' requirements. In addition, a media service provisioning use case shows the benefits of our framework. Finally, a proof-of-concept implementation of the framework is described and analyzed. This paper describes the first clean-slate architecture aligned with the work done within the ISO/IEC Future Network working group.

• Journal of Internet Computing and Services
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• v.6 no.3
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• pp.121-128
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• 2005

Recently, as the research of effective resource management for supporting of various next generation internet service, the admission control mechanisms using the dynamic provisioning methods in differentiated service networks are studied. However, even though admission control mechanism is applied to the network, there exits the unfairness of call blocking probability among the different bandwidth requested services. In this paper, we propose the new admission control policy heuristic algorithm that provides fairness of call blocking probability between the large bandwidth requested service and the small bandwidth requested service. The simulation results show that the proposed algorithm provides not only blocking probability fairness but also high bandwidth utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.653-663
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• 2002

UMTS/GPRS has its own QoS architecture, but additionally needs to support IP-QoS to provide Internet services. This paper describes an IP-QoS provisioning mechanism in the MPLS-based UMTS/GPRS network. We propose a QoS framework that includes the functional architecture of the MPLS-based GPRS networks and the efficient scheduling mechanism based on Diffserv model. The proposed scheduling mechanims is especially focused on the QoS support for real-time services. It also includes a new buffer management scheme that combines the priority queuing and weighted round robin method. The ns-2 simulator has been used to verify the validity of the proposed scheduling method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.844-848
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• 2002

In this paper, we present a VoIP service provisioning architecture based on MEGACO/H.248 which is one of the key protocols for VoIP services. MEGACO/H.248 is a media gateway control protocol standardized by both ITU-T and IETF, and many ITSPs, carriers, and vendors currently have a lot of interest in the protocol. MEGACO/H.248 is used by a softswitch a key component of the next generation VoIP network, in order to control various media gateways and provide seamless interworking between PSTN and Yon networks.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.3
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• pp.182-191
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• 2012

This paper proposes a high performance QoS (Quality of Service) traffic transmission scheme to provide real-time multimedia services in wireless networks. This scheme is based on both a traffic estimation of the mean rate and a header compression method by dividing this network model into two parts, core RTP/UDP/IP network and wireless access parts, using the IEEE 802.11 WLAN. The improvement achieved by the scheme means that it can be designed to include a means of provisioning the high performance QoS strategy according to the requirements of each particular traffic flow by adapting the header compression for real-time multimedia data. A performance evaluation was carried out to show the effectiveness of the proposed traffic transmission scheme.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.4
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• pp.27-44
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• 2000

In this study we consider a spares provisioning problem for repairable items in which a parts inventory system is incorporated. If a machine fails, a replacement part must be obtained at the parts inventory system before the failed machine enters the repair center. The inventory policy adopted at the parts inventory system is the (S, Q) policy. Operating times of the machine before failure, ordering lead times and repair times are assumed to follow a two-stage Coxian distribution. For this system, we develop an approximation method to obtain the performance measures such as steady state probabilities of the number of machines at each station and the probability that a part will wait at the parts inventory system. For the analysis of the proposed system, we model the system as a closed queueing network and analyze it using a product-form approximation method. A recursive technique as well as an iterative procedure is used to analyze the sub-network. Numerical tests show that the approximation method provides fairly good estimation of the performance measures of interest.