ATM망에서의 혼잡회피를 위한 동적 대역할당에 관한 연구

안기중 濟州大學校 産業技術硏究所 2000 산업기술연구소논문집 Vol.11 No.1

The ABR services in ATM networks are required to provide possibly non-zero minimum rate guarantees. achieve fairness, and minimize cell losses for data traffic. But they admit to the possibility of congestion. where the aggregate demand of sources exceeds the capacity of the network resources. A number of congestion management schemes have been proposed to allocate the available bandwidth fairly among the connections. In this paper a new congestion avoidance scheme is proposed to improve the convergence rate and link utilization by dynamic bandwidth allocation with a efficient control of cell leakage rate and explicit rate marking. A simulation is performed and the results are compared to the ERICA. The results show a noticeable performance enhancement in fast convergence, higher link utilization and low buffer requirements. which reduce the cell losses in the ATM switches while maintaining the fairness.

2차원 회적 유한어장 Fir 디지털 필터 설계에 관한 연구 ( A Design of Two Dimensional Optimal Finite Wordlength FIR Digital Filter )

안기중,박민용,이상배 대한전자공학회 1987 대한전자공학회 학술대회 Vol.1987 No.1

ATM망에서의 셀지연과 파라메터 제어에 관한 연구

안기중 濟州大學校 工科大學 産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.1

ATM Network supports various types of services, that have few intrinsic properties and it is difficult to know a priori. Therefore most traffic control mechanisms based on the fixed traffic parameters revealed some limitations to the network performance. In this paper, a dynamic parameter based traffic control scheme is proposed to enhance the network performance such as cell conformance ratio and cell loss probabilities in ATM networks. For every user connection source traffics can be superposed and cause some congestion in the network, especially in the multiplexing stages. This happens even if their total capacity is below the link capacity and its degree is getting worse with longer bursts which can be affected by CDV tolerance during cell conformance test. The proposed mechanism continuously monitors the buffer and based on its trend the CDV tolerance is adjusted and feedbacked to GCRA. This makes it possible to allocate more bandwith to each user connection and therefore achieve lower CLPs and higher cell conformance ratios.

ATM망에서의 동적 트래픽 억제 알고리즘

안기중 濟州大學校 産業技術硏究所 1997 산업기술연구소논문집 Vol.8 No.1

In this paper, a traffic enforcement algorithm is proposed to enhance the efficiency of traffic shaper in point of the cell conformance ratio with parameters negotiated during call connection setup in ATM network. This algorithm is based on Leaky Bucket but uses the limiting function of cell delay variations. which is controlled dynamically to absorb their propagation effects according to the input and output profiles. The simulation study shows its justifiability and its efficiency increasing for the traffic with higher burstiness. This allows more cells to be handled in the network and higher QOS can be provided to the users accordingly.

고속 64 비트 CMOS 뎃셈기의 구조 및 설계 ( An Architecture and Design of a Fast 64-bit Static CMOS Adder )

안기중,정덕균 대한전자공학회 1996 대한전자공학회 학술대회 Vol.1996 No.01

패킷교환 음성/데이타 네트워크에서의 성능 평가에 관한 연구

안기중 제주대학교 1991 논문집 Vol.33 No.-

본 논문에서는 ISND의 기본적인 multimedia services 중 voice 와 data traffic을 병합시킬 경우 기존의 단순한 TDM switching에서 발생할 수 있는 voice traffic의 증가에 따른 data traffic의 처리 시간 지연을 방지하기 위하여 voice call을 제어하고자 하였다. 만일 talkspurt에 있는 active call의 수가 congestion threshold level을 넘어설 경우 그 증가되는 call의 영향을 줄이기 위하여 voice packets 중 일부를 소거함으로써 data traffic 지연을 억제하였다. 이때 data traffic의 time delay와 throughput은 simulation 결과에서 알 수 있듯이 congestion threshold에 따라 민감하게 변화된다. 특히 data traffic 지연은 packet 소거율 β=0.25로 voice control을 하였을 경우 data 도착율λ??=240 packets/sec에서 0.07msec의 지연을 나타내어 정상시의 77.6%에 비해 99.9%정도 개선되었고, λ?=720packets/sec에서는 94% 정도의 개선율을 나타내고 있다. 한편 본 논문에서는 packet 소거율 β를 일정하게 유지하였으나 voice call 의 overload 상태가 심화될 경우 역시 시간 지연은 급격히 증가되는 것을 알 수 있었다. 따라서 packet 소거율을 overload하에서 voice call의 변화율이 함수로 간주할 경우 voice overload의 영향을 더욱 줄일 수가 있을 것이다. 하지만 packet 소거율이 증가함에 따라 voice quality degradation이 심화되고 기존의 packet interleaving 기법의 적용으로서는 그 품질을 개선하기가 힘들게 된다[Jayant 1981]. 따라서 앞으로는 이와같은 voice의 품질 저하 현상으로 부터의 회복 가능성과 packet 소거율을 연관지어 최적 제어점을 찾아야 할 것이다. In this paper a congestion control scheme is examined for the integrated packet voice/data traffic and the performance measure is evaluated to enhance the delay of data traffic under the circumstances of overloaded voice calls. Since voice has the real time characteristics, which reveal no accuse, higher priority over data in essentially required. When the voice calls are increased the data traffic cannot have any vacancies through the link and have to be buffered for later processing. This paper uses the voice control mechanism for such data traffic delay. The control mechanism applys the level control with checking the number of voice calls in talkspurt. When it is over some threshold level, the significant voice packets are discarded with some ratio to reduce the effect of voice overload and the time delay of data traffic.

집적 네트워크에서 데이타 흐름의 성능 평가에 관한 연구

안기중 제주대학교 1990 논문집 Vol.30 No.-

In this paper, optimal window flow control is proposed to improve the throughput performance subject to the tolerated data queueing delay, using a single server queueing model for the voice/data hybrid switch. Also the movable boundary strategy is considered to reallocate the data traffic to the unused voice slots and the throughput is maximized through the minimization of probability that the data queue is empty. Finally optimal criterion is verified by the system simulation.

ATM망에서의 혼잡회피를 위한 동적 대역할당에 관한 연구

안기중 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.1

The ABR services in ATM networks are required to provide possibly non-zero minimum rate guarantees, achieve fairness, and minimize cell losses for data traffic. But they admit to the possibility of congestion, where the aggregate demand of sources exceeds the capacity of the network resources. A number of congestion management schemes have been proposed to allocate the available bandwidth fairly among the connections. In this paper a new congestion avoidance scheme is proposed to improve the convergence rate and link utilization by dynamic bandwidth allocation with a efficient control of cell leakage rate and explicit rate marking. A simulation is performed and the results are compared to the ERICA. The results show a noticeable performance enhancement in fast convergence, higher link utilization and low buffer requirements, which reduce the cell losses in the ATM switches while maintaining the fairness.

ATM망에서의 셀 지연과 파라메터 제어에 관한 연구

안기중 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.1

ATM Network supports various types of services. that have few intrinsic properties and it is difficult to know a priori. Therefore most traffic control mechanisms based on the fixed traffic parameters revealed some limitations to the network performance. In this paper, a dynamic parameter based traffic control scheme is proposed to enhance the network performance such as cell conformance ratio and cell loss probabilities in ATM networks. For every user connection source traffics can be superposed and cause some congestion in the network. especially in the multiplexing stages. This happens even if their total capacity is below the link capacity and its degree is getting worse with longer bursts which can be affected by CDV tolerance during cell conformance test. The proposed mechanism continuously monitors the buffer and based on its trend the CDV tolerance is adjusted and feedbacked to GCRA. This makes it possible to allocate more bandwith to each user connection and therefore achieve lower CLPs and higher cell conformance ratios.

ATM망에서의 동적 트래픽 억제 알고리즘

안기중 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

In this paper, a traffic enforcement algorithm is proposed to enhance the efficiency of traffic shaper in point of the cell conformance ratio with parameters negotiated during call connection setup in ATM network. This algorithm is based on Leaky Bucket but uses the limiting function of cell delay variations, which is controlled dynamically to absorb their propagation effects according to the input and output profiles. The simulation study shows its justifiability and its efficiency increasing for the traffic with higher burstiness. This allows more cells to be handled in the network and higher QOS can be provided to the users accordingly.