• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.77-80
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• 2004

본 논문에서는 네트워크 및 시스템 측면에서 incoming traffic의 QoS 보장하기 위한 방법을 제안한다. 네트워크 측면에서는 outgoing traffic을 위한 처리율이 현재 incoming traffic의 처리율에 따라 동적으로 수정되도록 하였으며 시스템 측면에서는 incoming traffic중 홈 게이트웨이를 최종 목적지로 하는 트래픽을 처리하는 프로세스의 우선순위 및 CPU 사용량을 수정하도록 하였다. 테스트 베드 상에서 실험 결과를 통하여 제안한 방법이 incoming traffic의 QoS를 보장함을 확인하였다.

• Journal of Communications and Networks
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• v.15 no.6
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• pp.614-634
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• 2013

The proliferation of real-time multimedia services requires huge amounts of data transactions demanding strict quality-of-service (QoS) guarantees. Multicast transmission is a promising technique because of its efficient network resource utilization. However, high head-of-line (HOL) blocking probability and lack of service-specific QoS control should be addressed for practical implementations of multicast networks. In this paper, a topology aware fanout set division (TAFD) scheme is proposed to resolve these problems. The proposed scheme is composed of two techniques that reduce HOL blocking probability and expedite packet delivery for large-delay branches regarding multicast tree topology. Since management of global topology information is not necessary, scalability of the proposed scheme is guaranteed. Mathematical analysis investigates effects of the proposed scheme and derives optimal operational parameters. The evaluation results show that the TAFD scheme achieves significant delay reduction and satisfies required delay bounds on various multicast networks.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.219-231
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• 2005

Many applications in cluster computing require QoS (Quality of Service) services. Since performance predictability is essential to provide QoS service, underlying systems must provide predictable performance guarantees. One way to ensure such guarantees from network subsystems is to generate global schedules from applications'network requests and to execute the local portion of the schedules at each network interface. To ensure accurate execution of the schedules, it is essential that a global time base must be maintained by local clocks at each network interface. The task of providing a single time base is called a synchronization problem and this paper addresses the problem for system area networks. To solve the synchronization problem, FM-QoS (1) proposed a simple synchronization mechanism called FBS(Feedback-Based Synchronization) which uses built-in How control signals. This paper extends the basic notion of FM-QoS to a theoretical framework and generalizes it: 1) to identify a set of built-in network flow control signals for synchrony and to formalize it as a synchronizing schedule, and 2) to analyze the synchronization precision of FBS in terms of flow control parameters. Based on generalization, two application classes are studied for a single switch network and a multiple switch network. For each class, a synchroniring schedule is proposed and its bounded skew is analyzed. Unlike FM-QoS, the synchronizing schedule is proven to minimize the bounded skew value for a single switch network. To understand the analysis results in practical networks, skew values are obtained with flow control parameters of Myrinet-1280/SAN. We observed that the maximum bounded skew of FBS is 9.2 Usec or less over all our experiments. Based on this result, we came to a conclusion that FBS was a feasible synchronization mechanism in system area networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.100-107
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• 2007

Recently, a study of BcN(Broadband convergence Network) is progressing continuously, and it is important to improve the quality of the service according to subscribers because a scale of network is about to be larger. It is more important to manage QoS(Quality of Service) of all subscribers in layer 2 than layer 3 network since managing it in layer 3 network cost both additional processes and large hardware. Moreover, QoS based on Best-Effort service has been developed because tots of subscribers should use limited resource in BcN. However, they want to be supplied with different service even though they pay more charge. Therefore, it is essential to assign the different bandwidth to subscribers depending on their level of charge. The method of current Rate Limiter limits the bandwidth of each port that does not offer fair service to subscribers. The Rate Limiter proposed in this paper limits bandwidth according to each subscriber. Therefore, subscribers can get fair service regardless of switch structure. This new Rate Limiter controls the bandwidth of subscribers according to the information of learning subscriber and manages maximum performance of Ethernet switch and QoS.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3077-3085
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• 1999

Conventional caching system doesn't support Real-Time attributes and load balance. To solve these problems, this paper describes the design and implementation of the RIOP(Real-Time Inter-ORB Protocol) to provide QoS guarantees mechanism integrating RSVP and TAO ORB. Futhermore, it provides fast XCSLS(Extended Caching System for Load Balance) implementing main memory cache in Primary Server using locality of objects. In this paper, a key feature is presented : QoS enforcement, PS(Primary Server) and RS(Replicated Server)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1469-1476
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• 2015

We propose a beam selection algorithm that improves inter sector SIR using a code-book of a circular array antenna in multi-sector wireless mesh network environments. The proposed method improves SIR using a combination of fed back code-book and guarantees QoS of all nodes. Computer simulation exhibits the proposed scheme demonstrates 4.42dB higher SIR than that of the conventional code-book method, QoS with proportional fair is improved by 1.70dB and fact that all nodes are satisfied Qos is also shown.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.217-232
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• 2003

QoS routing can improve network performance while providing support for QoS guarantees. These benefits, however, comes with additional routing costs such as more complex and frequent route computation and the protocol overheads to exchange dynamic network state information. Moreover, little has been done to mininize the impact of the QoS traffic to the best effort traffic or to enhance the routine Performance of the best effort traffic when QoS routing is deployed. In this paper, it is proposed that a sewer based routing mechanism, which supports the QoS routing without incurring the QoS routing protocol overhead for the network state update exchanges and enhances the performance of the best effort traffic without affecting the performance of QoS routing. Simulation results show that the proposed scheme enhances the routing performance for the QoS traffic while reducing the routing protocol overhead. The routing performance of the best traffic is also improved with virtually no impact to the routine performance of the QoS traffic. The proposed scheme is shown to be especially effective when the ratio of QoS traffic is high, that is, when the impact of the QoS traffic to the performance of best effort traffic is significant.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3190-3198
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• 1999

Because of the rapid growth of the mobile communication, the need for the mobile internet access has grown up as well. since the current mobile communication network, however, is optimized for a voice communication system, which exclusively occupies a channel for a given time, it is not suitable for variable rate packet data. In order to support the mobile internet access, it is essential do design a reasonable packet switching network which supports the mobility. Since mobile packet network has longer latency, high speed switching and QoS are required to meet the user's requirements. In this paper, we suggest an resonable way to construct a network and its operation procedures utilizing GPRS(General Packet Radio Service) network and MPLS(Multi Protocol Label Switching) to provide a high speed switching and QoS mobile internet access. GPRS is used as a network which supports the mobility and MPLS guarantees the QoS and high speed IP protocol transmission based on the ATM switching technology.

• Journal of Korea Multimedia Society
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• v.9 no.7
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• pp.835-843
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• 2006

Multicast can send one copy of each packet to each member of the multicast group. Network resource is utilized effectively, consequently, it is suitable for one-to-many environments. reliability and flow control, however, are not supported basically, it is not suitable or transmission of multimedia data which have a time restriction. In this paper, we present a network model and a multicast retransmission scheme The proposed scheme remove ack-explosion from sender through local recovery and performs local retransmission when time restriction is satisfied on receiver by considering the state of receiver's buffer. Mathematical analysis and simulation are conducted to prove performance of the proposed scheme. The results are shown that the proposed scheme consumes a lower network bandwidth than the existing network model and guarantees QoS of receivers.

• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.667-676
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• 2001

We have solved a problem occurring in case that RSVP is applied to existing wired network in order to guarantee a QoS of multimedia traffic in mobile computing environment in this paper. If MN moves to another area when Mobile IP is applied to RSVP, HA makes new tunnel to FA because SESSION ID of MN is changed. However, we suggest MIP-DUDN method, which applied RSVP. Although MN moves to another area in this method, it does not make new tunnel because it eliminates the problem of existing Triangle Routing Problem. We design the new protocol of RMIP-DUDN and compare with the method of existing Mobile IP applied to RSVP.