• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.817-821
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• 1996

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.565-567
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• 1998

본 논문은 멀티미디어 멀티캐스트 혼잡 제어에서 발생하는 피드백 폭주 문제를 해결하기 위해 대표자 계층구조를 이용한 피드백 수렴 방법과 이에 따른 전송률 조정 방법을 제안하고 시뮬레이션을 통해서 이를 검증한다. 시뮬레이션 결과 적절한 파라미터의 설정하에 피드백 폭주 문제를 해경하고 혼잡하고 대처하여 전송률을 조정할 수 있음을 볼 수 있었다.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.69-72
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• 2007

인터넷에서 폭주상황이 발생한 후에는 네트워크 성능이 급격하게 저하되는 문제점을 개선하고자 RED 알고리즘이 제안되었으며, 현재 IETF 에서는 표준으로 사용되고 있다. 그러나 RED 알고리즘은 고정된 파라미터 값을 사용하여 가변적인 네트워크 트래픽 상황에 능동적으로 대처하지 못하는 문제점을 가지고 있다. 본 논문에서는 기존의 RED 알고리즘의 문제점인 고정된 파리미터 값 설정으로 인한 문제점을 해결하기 위하여 효율적인 RED 알고리즘을 제안한다. 제안한 알고리즘은 현재의 가변적인 트래픽 상태에 따라 패킷폐기확률을 조정하여 라우터와 같은 게이트에서의 폭주상황을 효율적으로 제어하도록 하였다. 또한 제한안 알고리즘은 NS-2를 이용하여 시뮬레이션을 수행함으로써 성능을 검증하였다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.374-376
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• 1998

ABR서비스는 ATM 망의 이용률을 증대시키고, 매우 버스트한 트래픽 응용을 지원하기위해 설계되었다. ATM 포럼에서는 망에서 소스의 셀 전송률을 조절하고 셀 손실을 최소화하기 위한 ABR 서비스 표준으로 폐쇄루프와 전송률기반의 폭주 제어 알고리즘을 채택하였다. 이러한 폭주 제어 알고리즘 중에서 대표적인 것이 ERIVCA(Explicit Rare Indication for Congestion Avoidance) 이다. 본 논문에서는 ERIVCA 의 견고성, 공평성 LAN/WAN 환경에 대해서 성능을 시험하고. 그 결과로 성능을 향상시키기 위해 개선된 최대-최소 구조를 제공한다. 또한 제안된 구조에 대한 시뮬레이션을 하여 기존 ERIVCA 알고리즘의 성능과 비교 분석한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1653-1660
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• 2003

In this paper, we proposed an enhanced TCP congestion control algorithm using RTT with congestion window parameter cwnd to minimize the effect of TCP congestion. The proposed scheme could avoid the occurrence of frequent congestion and decrease the delay caused by the recovery time and the using amount of switch buffer. Through the simulation, we showed that the proposed scheme cm acquire higher performance than the existing scheme. There are 22.56％ improvement at the average using buffer efficiency, and packet drop rate is 0.1％ which is less than existing scheme.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.42-51
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• 1998

This paper suggests a congestion control scheme for CL (ConnectionLess) overlay network using the feedback loops between CL user and CL server, between CL servers, and between end-to-end CL users, and the header translation table of CL server. The CL overlay network for CBDS(Connectionless Broadhand Data Service) defined by ITU-T((International Telecommunication Union-Telecommunication) consists of CL servers which route frames and links which connect between CL user and CL server or between CL servers. In the CL overlay network, two kinds of congestion, CL link congestion and CL server congestion, may occur. We considered the schemes to solve the congestion. link-by-link method[18] has used the ABR feedback loops of ATM layer between CL user and CL server or between CL servers, and the congestion table using header translation table of CL server. As in congestion of output virtual channel this method has an effect on all the traffic transmitting through the link, then it has an effect on the traffic that has not caused the congestion. As a result, the link utilization of output virtual channel that does not bring the congestion and outputs the traffic is decreased. To overcome this drawback of link-by-link, we proposed the hybrid method that are using the ABR feedback loops of link-by-link method, the feedback loop between CL users in end-to-end, the congestion table using and the header translation table. This scheme deals with teh congestion immediately by link-by-link loops and the header translation table, and then regulates the sending rate of CL user that causes the congestion by end-to-end loop.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1890-1906
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• 1997

A new ER feedback switch control algorithm, called EMRCA(Explicit Max-min Rate Control Algorithm), to control the ABR services traffic in the ATM networks, is proposed in this thesis. This scheme was interpreted the ACR variation residing on between a transient state and a stable state using the two thresholds that is the $TH_{high}$ and $TH_{low}$ in the queue to detect switch nodes congestion, and decreased the difference of minimum and maximum ACR all active connection to enhance the line bandwidth utilization. The proiposed scheme used a minimum and maximum rate of all active connections to select the connection whose the congestion rate inveoked, and uses a congestion detection mechanixm to prevent some potential cogestion by regulating selected contection.s The EMRCA scheme showed ACR variation more stable that the EPRCA scheme, also reduced buffer size of the switch, and achieved higher link utilization than the EPRCA scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.750-760
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• 1994

In this paper we proposed a multiplexing scheme of real time and non-real traffics in which a congestion control is embedded. Real time traffics are assumed to be nonqueuable and have preemptive priority over non-real time traffics in seizing the common output link, whereas the non-real time traffics wait in the common buffer if the output link is not available for transmission. Real time traffics are encoded according to the bandwidth reduction strategy, paticularly when congestion occurs among non-real time traffics. This scheme provides us an efficient way for utilizing the costly bandwidth resources, by accommodation as many real time traffics as possible with gauranteeing its mimimum bandwidth requirements, and also resloving the congestion encountered among non-real time traffics. We describe the system as a Markov queueing system, provide the analysis by exploiting the matrix geometric method, and present the performance for various performance measures of interest. Some numerical results are also provided.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.655-658
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• 2001

현재 인터넷의 서비스 중 동영상은 많은 대역폭을 차지하고 있으며 실시간적으로 전송되어야 하는 특성을 가지고 있다. 이러한 조건을 만족하기 위해서 Layered coding의 특성을 이용한 스케일러블 전송이 MPEG2를 통해 가능하게 되었다. 본 논문에서는 MPEG2의 스케일러블 전송을 바탕으로 송신측에서의 폭주제어와 함께 실시간 서비스를 제공하는 알고리즘을 제안한다. 본 알고리즘에서는 폭주 제어를 위해 Congestion Window을 사용하며 네트워크 속도를 측정하여 QoS(Quality of Service)를 보장한다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.9-12
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• 2000

In this paper, we carry out a performance study related to the Advanced Peer-to-Peer Network(APPN). For this particular network, it has been proposed to use the leaky bucket as a way of controlling congestion within the network. On the top of leaky bucket type rate based congestion control scheme for high speed networks, a user will typically operate an error control scheme for retransmitting lost and erroneous packets. We propose a Perform ance model in order to study the Interaction between a user's error control scheme and the leaky bucket congestion control scheme for high speed networks. Simulation results show that parameters such as the window size and the token generation rate in the leaky bucket are key factors affecting the end-to-end delay.