• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1108-1112
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• 1999

In this paper, we propose an efficient ABR multicast algorithm for ATM networks. In ABR multicast algorithim, the feedback consolidation is necessary to avoid excessive backward resource management (BRM) cells and to aggregate the information from BRM cells received from each branch. The proposed scheme is shown to achieve fast transient response to the congestion status on a branch as well as effectively eliminate the consolidation noise through system simulation.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.379-382
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• 2001

In this paper, a new enhanced early fair rate allocation(EFRA＋) algorithm is proposed for ATM switches supporting ABR service. The central issue of explicit rate control algorithms for ABR service is the computation of max-min fair rates for every connection. The EFRA＋ inherits the main feature of the EFRA, uses the connection control information during the connection setup to prevent potential congestion in switches, and enhances the computation method of the max-min fair rate.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.9-12
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• 2000

본 논문에서는 기존의 지상 ATM망의 제어기법을 바탕으로 위성망으로 확대 적용할 수 방안으로 기존의 지상 ATM망의 막힘제어 기법중 ERICA스위치 알고리즘을 적용하였으며, 기존의 ERICA스위치 알고리즘은 지상과 위성간의 긴 전파지연시간을 고려하지 않아 위성내의 막힘을 알려주는 정보가 지구국까지 전달되어 다시 위성에 전달될 때 위성의 막힘 상태변화로 인한 손실이 발생할 수 있다 본 논문에서는 이러한 손실을 피하기 위한 제어구조에 대해서 다루었다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1610-1619
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• 1998

The ABR service class provides feedback based traffic control to transport bursty data traffic efficiently. Feedback based congestion control has first been studied to be applied to unicast connections. Recently. several congestion control algorithms for multicast connections have also been proposed as the number of ABR applications requiring multicast increases. With feedback based congestion control, the effectiveness of a traffic control scheme diminishes as propagation delay increases. Especially for a multicast connection, a remote destination may suffer unfair service compared to a local destination due to the delayed feedback. Amelioration of the disadvantages caused by feedback delay is therefore more important for remote destinations in multicast connections. This paper proposes a new switch behavior to provide effective feedback based mathc control for rentoh destinations. The proposed switches adjust the service rate dynamically in accordance woth the state of the downstream, that is, the congestion of the destinaion is immediately controlled by the nearest apstream switch before the source to ramp down the transmission rate of the connection. The proposed switch has an implementation overhead to have a separate buffer for each VC to adjust the service rate in accordance with a backward Rm cell of each VC. The buffer requirement id also increased at intermediate switches. Simulation results show that the proposed switch reduces the cell loss rate in both the local and the remote destinations and slso amelioratd the between the two destinations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1359-1371
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• 1999

In this paper, we propose an efficient explicit rate (ER) feedback switch algorithm for available bit rate (ABR) flow control. In order to improve the disadvantages of existing ER feedback switch algorithms with congestion avoidance, the proposed scheme adjusts the target utilization dynamically according to the queue length and its growth rate. also, we investigate the performance of the proposed switch algorithm and compare it with ERICA and NIST switches using simulation. Simulation results show that the proposed switch algorithm can control the cell emission rate of a source rapidly according to variations of available link bandwidth by using dynamic adaptation of target utilization. It also exhibits a better performance than the existing ER feedback switches in terms of queue length and link utilization.

• Journal of Communications and Networks
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• v.6 no.1
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• pp.38-45
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• 2004

The ABR point-to-multipoint connection is now playing a more important role than before. Many consolidation algorithms have been proposed to solve the consolidation noise problem and the slow transient response problem. But few timeout algorithms are proposed to handle the non-responsive branches for the multicast connections. Chen’s algorithm needs exchanging control messages between switches [9]. Besides, it may mistake a responsive branch as a non-responsive branch because of fast changes in source rates, which causes wrong information in BRM cells and may lead to network congestion and data losses in the responsive branch. We propose a simple timeout algorithm which can handle the non-responsive branches without exchanging message between switches. The timeout value for each switch is computed locally. Simulation results show that the proposed timeout algorithm can efficiently handle the non-responsive branches and utilize the available bandwidth within a small period of time. In addition, our algorithm could handle the situation when the source rates change quickly.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.805-814
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• 2001

In this paper, we propose a new scheduling algorithm that guarantees the delay property of real-time traffic, not considered in previous DWRR(Dynamic Weighted Round Robin) algorithm and also transmits non-real-time traffic efficiently. The proposed scheduling algorithm is a variation of DWRR algorithm to guarantee the delay property of real-time traffic by adding cell transmission method based on delay priority. It also uses the threshold to prevent the cell loss of non-real-time traffic due to cell transmission method based on delay priority. Proposed scheduling algorithm may increase some complexity over conventional DWRR scheme because of cell transmission method based on delay priority. However, the consideration of delay priority can minimize cell delay and require less size of temporary buffer. Also, the results of our performance study shows that the proposed scheduling algorithm has better performance than conventional DWRR scheme due to reliable ABR service and congestion avoidance capacity.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.57.1-57
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• 2001

The objectives of congestion control in ATM (Asynchronous Transfer Mode) networks are maximum utilization of network resources, acceptable level of low cell loss and fairness among all VCs (Virtual Connections). In this paper, we present a congestion control algorithm which is based on state space model, The proposed controller uses optimal control algorithms (LQR, Mixed-LQR), where control parameters can be designed to ensure the stability of the control loop in a control theoretic sense, over the propagation delay. We show how the control mechanism can be used to design a controller to support ABR service based on feedback of explicit rates. Simulation results are presented to substantiate our claim.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.227-232
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• 2005

A network of Packet based switch Mode will be required to carry the traffics(CVR,VBR, UBR, ABR) generated by a wide range of services. Packet based Network services the quality-of-Service (QoS) management of traffic sources and bandwidth. Besides efficiency and throughput services are achieved in the multimedia traffic sent in the network. In this paper. the scheduler transmits the safe packet, drop the unsafe packet and evaluate unsafe packet as the requirement of the delay avoiding the network congestion for improving the QoS of the multimedia network In this paper. we Propose the scheduling algorithm which evaluates and drops the packet . The suggested model performance of the switch is estimated and simulated in terms of the delay by computer.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.245-250
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• 2005

A network of Packet based switch Mode will be required to carry the traffics(CVR,VBR, UBR, ABR) generated by a wide range of services. Packet based Network services the Qualify-of-Service (QoS) management of traffic sources and bandwidth. Besides efficiency and throughput services are achieved in the multimedia traffic sent in the network. In this paper, the scheduler transmits the safe packet, drop the unsafe packet and evaluate unsafe Packet as the requirement of the delay avoiding the network congestion for improving the QoS of the multimedia network. In this paper, we Propose the scheduling algorithm which evaluates and drops the packet The suggested model Performance of the switch is estimated and simulated in terms of the delay by computer.