• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.387-390
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• 2001

In this paper, we propose methods for designing the Virtual Private Network (VPN) which guarantees a strict Quality of Service (QoS) over A TM networks. The required Quality of Service is a very strict Cell Loss Probability, and it is guaranteed by pro riding equivalent bandwidth which is computed so that the provided bandwidth is sufficient to guarantee that requirement. We consider two network architectures for constructing VPM, the customer pipe scheme and the Hose scheme, and we propose a method to compute the amount of the required bandwidth for the two schemes. Finally, we investigate the implication of the scheme via numerical experiments.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.31-38
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• 1995

In this paper, we consider the leaky bucket parameter dimensioning problem in the presence of the cell delay variation(CDV) which arises at the customer premises network dud to the multiplexing with other traffic streams. We consider an ATM multiplexer in which a single CBR stream and several heterogeneous VBR traffic streams are multiplexed. Choosing an MMPP model for the bursty traffic streams, we derive an (MMPP+DD)/D/1/K queueing model for the evaluation of the CDV experienced by the CBR stream. We first evaluate the equilibrium queue length distribution embedded at tagged-cell arrival-time instants, based on whcih we calcuate the inter-cell time distribution and the distribution kof the number of tagged-cell departures in an arbitrary interval. Then we apply the analysis to the dimensionging problem of the leaky bucket parameters, examining how the employed traffic model affects the determination of the bucket size. Through numerical examples, we confirm that the Poisson traffic model can underestimate the bucket size, thus causing a considerable blocking probability for compliant use cells while the MMPP model can optimally design the bucket size which keeps the blocking probability under the target value.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.410-415
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• 2005

Recent measurements of local-area and wide-area traffic have shown that network traffic exhibits at a wide range of scales - Self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all for design and dimensioning of next generation communication network, traffic model that are reflected burstness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, when different many data traffic being integrated under various environments is arrived to communication network, Hurst Parameter's change is analyzed and compared with simulation results.

• Journal of Communications and Networks
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• v.18 no.2
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• pp.162-172
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• 2016

The placement of the complete baseband processing in a centralized pool results in high data rate requirement and inflexibility of the fronthaul network, which challenges the energy and cost effectiveness of the cloud radio access network (C-RAN). Recently, redesign of the C-RAN through functional split in the baseband processing chain has been proposed to overcome these challenges. This paper evaluates, by mathematical and simulation methods, different splits with respect to network level energy and cost efficiency having in the mind the expected quality of service. The proposed mathematical model quantifies the multiplexing gains and the trade-offs between centralization and decentralization concerning the cost of the pool, fronthaul network capacity and resource utilization. The event-based simulation captures the influence of the traffic load dynamics and traffic type variation on designing an efficient fronthaul network. Based on the obtained results, we derive a principle for fronthaul dimensioning based on the traffic profile. This principle allows for efficient radio access network with respect to multiplexing gains while achieving the expected users' quality of service.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.62-68
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• 2007

A conceptual thermal design is performed for the optical payload system of a geostationary satellite. The optical payload considered in this paper is GOCI(Geostationary Ocean Color Imager) of COMS of Korea. The radiative thermal control system is employed in order to expect a small thermal gradient in the telescope structure of GOCl. Two design margins are applied to the dedicated radiator dimensioning, and three kinds of configuration to the heater power sizing. A Monte-Carlo ray tracing method and a network analysis method are utilized to calculate radiative couplings and thermal responses respectively. At the level of conceptual design, sizing thresholds are presented for the radiator and heater on the purpose of determining the mass and power budget of the spacecraft.

• ETRI Journal
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• v.17 no.1
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• pp.23-36
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• 1995

We present a performance evaluation model of cell reassembly mechanism in an ATM switching system. An ATM switching system may be designed so that communications between processors of its control part can be performed via its switching network rather than a separate inter-processor communications network. In such a system, there should be interface to convert inter-processor communication traffic from message format to cell format and vice versa, that is, mechanisms to perform the segmentation and reassembly sublayer. In this paper, we employ a continuous-time Markov chain for the performance evaluation model of cell reassembly mechanism with individual buffering, judicially defining the states of the mechanism. Performance measures such as message loss probability and average reassembly delay are obtained in closed forms. Some numerical illustrations are given for the performance analysis and dimensioning of the cell reassembly mechanism.

• IE interfaces
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• v.13 no.4
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• pp.709-716
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• 2000

In this paper, We analyze a capacity dimensioning and performance of the access line to the X.25 packet network when the AO/DI internet service is connected via D-channel. We show the forecasting methodology of the traffic demand of the D-channel internet services when the TDX-1OA switching system accommodates the target number of subscriber. Based on the traffic demand forecast, the required capacity of the access line is suggested to prevent bottleneck problem in the access line to the X.25 packet network.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1616-1640
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• 2006

In this paper, we deal with a network optimization problem arising from the deployment of Ethernet-based BcN access network. BcN convergence services require that access networks satisfy QoS measures. BcN services have two types of traffics: stream traffic and elastic traffic. Stream traffic uses blocking probability as a QoS measure, while elastic traffic uses delay factor as a QoS measure. Incorporating the QoS requirements, we formulate the problem as a nonlinear mixed-integer programming model. The proposed model seeks to find a minimum cost dimensioning solution, while satisfying the QoS requirement. We propose tabu search heuristic algorithms for solving the problem, and simulate tabu result. We demonstrate the computational efficacy of the proposed algorithm by solving a network design problem.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.7-11
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• 2004

There are many problems that must solve to construct next generation high-speed communication network. Among these, item that must consider basically is characteristics analysis of traffic that nows to network Traffic characteristics of many Internet services that is offered present have shown that network traffic exhibits at a wide range of scals-self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all, for design and dimensioning of next generation communication network, traffic model that are reflected burstiness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, the calculation equation is derived considering queueing delay and self-similarity of data traffic art compared with simulation results.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.175-181
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• 2005

Recent measurements of local-area and wide-area traffic have shown that network traffic exhibits at a wide range of scales-Self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all for design and dimensioning of next generation communication network, traffic model that are reflected burstness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, when different many data traffic being integrated under various environments is arrived to communication network, Hurst Parameter's change is analyzed and compared with simulation results.