• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.261-264
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• 1998

Controlled transfer (CT) capability, a new ATM transfer capability (ATC) for high-speed data applications which using credit-based flow control, has recently been proposed and studied in ITU-T. In this paper, we review the existing dyanmic buffer allocation schemes and propose an improved scheme. Also, we compare the performances of the existing buffer allocation methods such as static allocation, flow controlled virtual channels (FCVC), and zero queueing flow control (ZQFC) with the proposed method through simulation. Simulation results show that the proposed scheme exhibits a better performance than the existing schemes in terms of throughput, fairness, queue length and link utilization.

• Journal of Digital Contents Society
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• v.2 no.2
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• pp.129-138
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• 2001

With the explosive growth and pervasive of the Internet, dynamic bandwidth allocation is nessary for ATM streams that carry various traffic. In order to provide quality of service(QoS) guarantees and to give the minimum cell rate, new bandwidth allocation scheme requires to be implemented. DFBA(Differential Fair Buffer Allocation) scheme is one of the methods for ATM GFR(Guaranteed Frame Rate) services. DFBA scheme treats cells selectively in a region between low buffer occupancy threshold and high buffer occupancy threshold. A big unbalance is introduced when the value being selected by DFBA scheme is greater than minimum rate. In a try to reduce the unbalance modified DFBA scheme is proposed. Selecting parameter according to the situation of network, this scheme is very effective to control the bandwidth in the various network situation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.10
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• pp.24-33
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• 2001

Delay, delay variation and packet loss rate are principal QoS(Quality of Service) elements of packet communication. This paper proposes a new buffer allocation mechanism to improve the packet loss performance in such a situation that multiple logical buffers share a single physical memory buffer. In the proposed buffer allocation mechanism, the movement of dynamic threshold follows a curved track instead of a straight line which is used in the DT(dynamic threshold) mechanism. In order evaluate the effectiveness of the proposed mechanism, it is compared with the existing previously proposed mechanisms in several aspects including NC(no control), ST(Static Threshold) and DT mechanisms.

• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.391-398
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• 2008

To provide IPTV service over mobile networks, the mechanism that reduce packet loss and interrupt of multimedia service during the handover should be supported. Especially, buffering based mechanism is preferable for supporting IPTV services in the way of preserving streaming service using stored data and recovering non-received data after handover. But previous research doesn't consider the buffer allocation for applying various environments which can change handover time or end to end delay of relay node. This paper propose DBAHAJ mechanism that optimize buffer size of mobile nodes and relay node for supporting seamless IPTV service over mobile environments. Mobile node determines buffer size by checking handover time and maximum difference of sequence to keep playing video data. And multicast agent recovers packet loss during the handover by sending buffered data. By these two procedure, node supports seamless IPTV service on mobile networks. We confirm performance of this mechanism on NS-2 simulator.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.410-419
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• 2003

The buffer cache of general operating systems such as Linux manages file data by using global block replacement policy and read ahead. As a result, multimedia data with a low locality of reference and various consumption rate have low cache hit ratio and consume additional buffers because of read ahead. In this paper we have designed and implemented a new buffer allocation algorithm for multimedia data on Linux. Our approach keeps one read-ahead cache per every opened multimedia file and dynamically changes the read-ahead group size based on the buffer consumption rate of the file. This distributes resources fairly and optimizes the buffer consumption. This paper compares the system performance with that of Linux 2.4.17 in terms of buffer consumption and buffer hit ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.1
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• pp.53-63
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• 1997

In this paper, we present a new macroblock-based bit allocation scheme in multiple MPEG-1 video encoders system and a single multiplexer over a single channel. The proposed scheme models the relations between fate(Bits/MB) and distortion(MSE/MB), rate and quantizer parameter(QP), distortion and quantizer parameter, respectively, in the same form. By using these relations, we minimize the Larangian cost function to obtain a bit allocation scheme based on macroblock unit. Experimental results show that the proposed scheme can reduce MSE compared to other conventional buffer-based rate control methods, i.e. independent buffer control method and shared common buffer control one. And we confirmed, through computer simulation, that the proposed scheme can be effectively modified to maintain the objective quality of a specific video service at a constant level.

• ETRI Journal
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• v.31 no.1
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• pp.86-88
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• 2009

In this letter, we consider an m-node tandem queue (queues in series) with a Poisson arrival process and either deterministic or non-overlapping service times. With the assumption that each node has a finite buffer except for the first node, we show the non-increasing convex property of stationary waiting time with respect to the finite buffer capacities. We apply it to an optimization problem which determines the smallest buffer capacities subject to probabilistic constraints on stationary waiting times.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.9
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• pp.36-48
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• 1999

Controlled transfer (CT) service has been recently proposed as a new ATM transfer capability for high-speed data applications, which used a credit-based flow control. This paper investigates buffer allocation schemes for CT service and proposes an improved dynamic bugger allocation scheme. In order to improve the responsiveness to a congestion, the proposed method is considered the load factor of a link when determining the amounts of virtual connection (VC)s buffer allocation. Also, in this paper we compare the performance of the proposed method with those of the existing buffer allocation methods such as flow controlled virtual channels (FCVC) and zero queueing flow control (ZQFC) through simulation. Simulation results show tat the proposed scheme exhibits a better performance than the existing schemes in terms of throughput, fairness, queue length and link utilization.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.73-78
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• 2002

In WATM networks, in order to perform dynamic slot allocation required slots of mobile terminals are estimated based on DP (Dynamic Parameter) reflecting characteristics of traffic. In VBR (Variable Bit Rate) traffic, slot allocation is done at MT considering both time-dependent characteristics and QoS (Quality of Service) requirements. In this paper, DPs-buffer state information and buffer state change-are transmitted through in-band signaling. BS (Base Station) performs dynamic slot allocation considering traffic characteristics of each MT (Mobile Terminal), in other words, buffer state information informs the potentiality of 'buffer full state'to BS if MT buffer is over the specific threshold value and buffer state change notifies change in buffer state of incoming cells to MT. If buffer state information is equal to 'low (more than threshold)' and 'abrupt increase' it generates 'buffer full' state cell transmission delay or cell loss might occur. At this time BS should assign additional slots to MT, and then MT consumes cells in its buffer. In simulation, the proposed scheme shows better performance in cell delay and loss than EPSA (Estimation-Prorated Slot Assignment) in-band scheme.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.11
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• pp.25-33
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• 1997

The end-to-end rate-based control mechanism is used for the flow control of the ABR service to allow much more flexibility in ATM switching system. To accommodate the ABR service effciently many algorithms such as EFCI, EPRCA, ERICA, and CAPC2 have been proposed for the switch algorithm. ABR cells and related RM cells are received at the ATM switch fabric transparently without any processing. And then cells received from the traffic source are queued in the ABR buffer of switching system. The ABR buffer usually has some thresholds for easy congestion control signal transmission. Whatever we use, therefore, these can be many ABR traffic control algorithms to implement the ABR transfer capability. The genertion of congestion indicate signal for ABR control algorithms is determined by ABR buffer satus. And ABR buffer status is determined by ABR cells transfer ratio in ATM switch fabrics. In this paper, we presented the functional structures for control of the ABR traffic capability, proposed the readout scheduling, cell slot allocation of output link and the buffer allocation model for effective ABR traffic guranteeing with considering CBR/VBR traffics in ATM switch. Since the proposed readout scheduling scheme can provide more avaliable space to ABR buffer than existing readout scheduling scheme, generation rate of a SEND signal, that is, BCN signal in destination node can be increased for ABR call connection. Therefore, the proposed scheme, in this paper, can be appropriate as algorithm for effective ABR traffic service on output link of ATM switching node.