• Journal of Korea Multimedia Society
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• v.13 no.11
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• pp.1594-1609
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• 2010

In the case that multiple services are in race condition for limited I/O resource, the services or processes with lower priority occasionally occupy most of limited I/O resource. And it decreases QoS and performance of important services and makes it difficult to efficiently use limited I/O resource. Although system administrator allocates I/O resource according to priority of process, he/she can't know or expect how much resource will be used by the specific process. Due to these reasons, it causes the problem that he/she can't guarantee the service QoS and performance stability. Therefore, in this paper, we propose service based disk I/O control supporting predictable I/O bandwidth to resolve upper problems. Proposed I/O control guarantees the service QoS and performance stability by supporting the service based predictable I/O bandwidth and it makes limited I/O resource to be efficiently used in respect of service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6C
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• pp.571-580
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• 2002

In this paper, we relatively differentiate maximum delay for each Assured Service subclass in Differentiated Services by allocating bandwidth to each subclass differently. To maximize the throughput for the In-profile traffic and the link utilization, we propose a Cofiguration method of RIO and the admission control criterion based on the buffer size determined by the network topology and the ratio of bandwidth allocated to each subclass. Simulation results show that the proposed method can calculate the capacity to guarantee the QoS for the Assured Service and maximize the throughput for the In-profile traffic and the link utilization by applying the RIO parameter values set through the proposed configuration method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1100-1105
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• 2003

In this paper, we propose a solution, called DQDMR, for generating delay-constrained bandwidth- appropriated multicast routing trees to reduce end-to-end delay and conserved bandwidth resources. At the current router system the router keep the information of link which neighboring node in the routing table to guarantee QoS(Quality of Service). When we construct multicast tree, DQDMR algorithm dynamically adjusts the path in the least delay and appropriate bandwidth. Through simulations comparing to another multicast algorithms, we reach a conclusion that DQDMR algorithm can simply and dynamically adjusts the construction of multicast tree in hight-speed and conserve bandwidth resources.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.441-447
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• 2003

Recently there is a growing Interest In mobile cellula r network providing multimedia service. However, the link bandwidth of mobile cellular network is not sufficient enough to provide satisfactory services to use rs. To overcome this problem, an adaptive framework has been proposed in this study, we propose a new method of estimating DPR(degradation period ratio) in an adaptive multimedia network where the bandwidth of ongoing call can be dynamically adjusted during its lifetime. DPR is a QoS(quality of service) parameter which represents the ratio of allocated bandwidth below a pre-defined target to the whole service time of a call. We improve estimation method of DPR using DTMC(discrete time Markov chain) model. We also calculate mean degradation period and degradation probability more precisely than in existing studies. Under Threshold CAC(call admission control) algorithm, we present analytically how to guarantee QoS to users and illustrate the method by numerical examples. The proposed method is expected to be used as one of CAC schemes in guaranteeing predefined QoS level of DPR

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.709-716
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• 2005

QoS is an important requirement of the FTTH (Fiber To The Home) subscriber in access network using E-PON (Ethernet Passive Optical Network). In this research, we describe the structure of the access network and propose a bandwidth guarantee scheme for subscriber and service according to the requirements of the subscriber, service and system. This scheme uses two kinds of the classification table, which are called 'service classification table' and 'subscriber classification table.' Using the classification table, we can identify the flow of the subscriber and service. Also, we compute the number of hash table entry to minimize the loss ratio of flows using the M/G/k/k queueing model. Finally, we apply the DRR scheduling through virtual queueing per subscriber instead of the aggregated class.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.156-166
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• 2005

Ethernet passive optical network is an economical and efficient access network that has received significant research attention in recent years. A MAC(Media Access Control) protocol of PON, the next generation access network, is based on TDMA(Time Division Multiple Access) basically. In this thesis, we addressed the problem of dynamic bandwidth allocation in QoS based Ethernet PONs. We augmented the bandwidth allocation to support QoS in a differentiated services framework. Our differentiated bandwidth guarantee allocation(DBGA) allocates effectively and fairly bandwidths among end users. Moreover, we showed that DBGA that perform weighted bandwidth allocation for high priority packets result in better performance in terms of average and maximum packet delay, as well as network throughput compared with existing dynamic bandwidth allocations. We used simulation experiments to study the performance and validate the effectiveness of the proposed bandwidth allocations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.7
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• pp.22-29
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• 2002

The Gauranteed Frame Rate service category was proposed by the ATM Forum as an enhancement to the UBR service. This service aims to support minimum cell rate gaurantee for each virtual connection and allow any excess bandwidth in the network to be shared among the contending VCs in a fair manner. We propose a new buffer management algorithm for GFR service through FIFO queuing discipline. Proposed scheme can provide minimum bandwidth guarantee for GFR VCs as well as improve the fairness among the competing GFR VCs on a single FIFO queue. From simulation results, we demonstrate the proposed scheme fulfills the requirement of GFR service as well as improves the TCP throughput.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5174-5190
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• 2016

Recent years have witnessed an explosive growth of mobile devices, mobile cloud computing services offered by these devices and the remote clouds behind them. In this paper, we noticed ultra-low latency service, as a type of mobile cloud computing service, requires extremely short delay constraints. Hence, such delay-sensitive applications should be satisfied with strong QoS guarantee. Existing solutions regarding this problem have poor performance in terms of throughput. In this paper, we propose an end-to-end bandwidth resource reservation via software defined scheduling inspired by the famous SDN framework. The main contribution of this paper is the end-to-end resource reservation and flow scheduling algorithm, which always gives priority to delay sensitive flows. Simulation results confirm the advantage of the proposed solution, which improves the average throughput of ultra-low latency flows.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.238-244
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• 2007

Guaranteed Frame Rate(GFR), recently approved by the ATM Forum, expects to become an important service category to efficiently support TCP/IP traffic in ATM networks. The GFR service not only guarantees a minimum service rate at the frame level, but also supports a fair share of available bandwidth. We proposed new scheduling scheme for the GFR service. Proposed scheme provides priority to VCs and high priority to a VC which have more untagged cells in buffer. High priority VCs have much more serviced than low priority. Proposed scheme can provide MCR(minimum cell rate) guarantee and fair sharing to GFR VCs. Computer simulation results show that proposed scheduling scheme provide a much better performance in TCP goodput and fairness than previous scheme.

• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.495-507
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• 2005

Measuring the end-to-end available bandwidth in the Internet is a useful tool for distributedapplication services or QoS (Quality-of-Service) guarantee. To measure the end-to-end available bandwidth, Single-hop Gap model-based packet train measurement techniques are well-known. However, the error of packet train output gap can happen by network topologies. This error of the output gap causes the inaccuracy of the available bandwidth measurement. In this paper, we propose a new end-to-end available bandwidth measurement technique with accurate capacity measurement and fast convergence methods. To solve the erroneous capacity measurement problem of the back-to-back packet train transmission, we propose a new available bandwidth measurement method by decoupling the capacity measurement with the initial gap of the packet train. Also, we propose a new technique to predict the proper initial gap of the packet train for faster convergence. We evaluate our proposed method by the simulation in various topologies comparing with previous methods.