• Korean Management Science Review
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• v.19 no.1
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• pp.29-38
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• 2002

Due to the rapid increase In the Internet traffic volume, ISPs are faced with the definite need of the expansion of server capacity. In order to Provide prompt services for customers and still prevent excessive facility cost, it is critical to determine the optimum level of internet server capacity. The purpose of this Paper is to provide a simple but effective strategy on the expansion of servers capacity according to the increase in internet traffic. We model an internet server as an M/G/m/m queueing system and derive an efficient method to compute the loss probability which, In turn, Is used as a basis to determine proper server capacity. The Process of estimating the traffic parameter values at each server based on log data analysis is also given. All the procedures are numerically demonstrated through the process of analyzing actual log data collected from a game company.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.4
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• pp.216-223
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• 2013

As the fast growth of using Internet, the requests of clients having different types and pressing loads on the server have been increased in World Wide Web. Thus the interesting issue is how to measure the real capacity of a Web Server. There have been much recent studies about measuring the capacity of web server. But the cause of Server response time delay is not just server itself but also network packet loss. To measure the practical capacity of web server, we generate scalable clients using Posix Thread, transport packets which were generated by scalable clients to the server using UDP and receive the packets which were the remain packet from network packet loss using TCP. In this paper, we propose a method to measure the practical capacity of a web server using the Scalable Clients based on Posix Thread and the transport on Application level.

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.33-43
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• 1998

To evaluate the server performance and forecast capacity requirements, we carry out simulation of Multimedia-on-demand(MOD) server. In multimedia service environment, especially for on-demand service, one of the key problems is capacity planning, which requires ensuring that adequate computer resources will be available to meet the future workload demands in a cost-effective manner. In this paper, we design and implement a simulation model for MOD server with failures of components (e.g., processors, disks and networks). By acquisition of utilization and queue length parameters, we can estimate desirable capacity of server components with various arrival rates of customers and failure rates of components. For a given failure probability, we also compute packet delay probability and reliability of the server. It is possible to derive some important design information of the MOD server by using the above parameters.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1866-1874
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• 2008

Existing web server lowers the whole capacity of system because of the problem on the processing load of server by closing connection increasing code handshake operation, and remarkable decrease of server capacity if it is the state of overload. Also, there occurs disadvantages of increasing connection tine about client's request and response time because handling of client's multi-requests is not smooth because of thread block and it requests a lot of time and resources for revitalization of thread. Therefore, this paper proposes the extended web server which provides the technique for delay handling and improves the overload of server for better system capacity, communication support, and the unification which is the advantage of web service. And it evaluates the existing system(implemented at Tomcat 5.5) and the proposed mobile web server architecture. The extended server architecture provides excellent exchange condition for system capacity and evaluates improved web server architecture which combines multi-thread with thread pool. The proposed web service architecture in this paper got the better result of improved capacity benefit than the evaluation result of original Tomcat 5.5.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.343-350
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• 2010

In the existing design of web server architecture, data encryption technique is used to keep the reliability, stability, and safety of web service. But the use of data encryption technique wastes the work of cpu while decreasing throughput of web server and increasing average response time so that it shows negative effect on the capacity of web application server. Also, the latest web applications require security and safety for the safe internet communication. Therefore, this paper suggests the improved web server which uses thread pool and Non-blocking I/O adding new web service modules to the existing web server for the safe web service, provides reliability and safety to show the safe web service capacity. And we compare and evaluate the safety and capacity through experiment on the existing traditional Tomcat based web server and the proposed system to evaluate the safety and capacity of the proposed web server system.

• The KIPS Transactions:PartC
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• v.11C no.3
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• pp.309-318
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• 2004

AAAv6-based Diameter method is using in the user authentication to satisfy the users' increasing user authentication demand and to supply a safe communication between mobile node and server in the Mobile IP. therefore, In this paper, We design a model of server capacity based on EAP-TLS that in one of AAAv6 models with mobility among domains to get the optimized capacity index of the server for user authentication accomplishment. We elicitat the authentication capacity index for each server of which is accomplishing in user authentication using DSA/RSA algorithm and purpose the optimized condition for the AAAv6 capacity by the index.

• Journal of Internet Computing and Services
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• v.17 no.2
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• pp.1-9
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• 2016

Users are provided infrastructure such as CPU, memory, network, and storage as IaaS (Infrastructure as a Service) service on cloud computing environments. However storage instances cannot support the maximum storage capacity that SQL servers can use, because the capacity of instances provided by service providers is usually limited. In this paper, we propose a method of securing mass storage capacity for SQL servers by sharing network disks with limited storage capacity. We confirmed through experiments that it is possible to secure mass storage capacity, which exceeds the maximum storage capacity provided by an instance with Amazon EBS on Amazon EC2 Windows environments, and it is possible to improve the overall performance of the SQL servers by increasing the disk capacity and performance.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.585-591
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• 2006

Generalized Processor Sharing(GPS) model provides instantaneous fair services to currently backlogged sessions. Since this fair service distributes server capacity to backlogged sessions in proportion to their weights, the fairness is only valid between the sessions serviced at the same time. From the long time view, however, this fair service provides different server capacity with one session or another, even if these sessions have the same weights. This paper proposes a cumulative fair service(CFS) model to provide fair server capacity to all sessions in the long time view. This model provides fair service in session Viewpoint because it distributes server capacity in proportion to the weights of sessions. The model and an algorithm referencing that model are analyzed for their properties and performances. Performance evaluations verify that the proposed algorithm provides proportional service capacity to sessions in the long time view.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.286-295
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• 2012

To meet the increased demand of video-on-demand (VoD) services, peer-to-peer (P2P) mesh-based multiple video approaches have been recently proposed, where each peer is able to find a video segment interested without resort to the video server. However, they have not considered the constraint of the server's upload bandwidth and the fairness between upload and download amounts at each peer. In this paper, we propose a novel P2P VoD streaming system, named peer cache adaptation (PECAN) where each peer adjusts its cache capacity adaptively to meet the server's upload bandwidth constraint and achieve the fairness. For doing so, we first propose a new cache replacement algorithm that designs the number of caches for a segment to be proportional to its popularity. Second, we mathematically prove that if the cache capacity of a peer is proportional to its segment request rate, the fairness between upload and download amounts at each peer can be achieved. Third, we propose a method that determines each peer's cache capacity adaptively according to the constraint of the server's upload bandwidth. Against the proposed design objective, some selfish peers may not follow our protocol to increase their payoff. To detect such peers, we design a simple distributed reputation and monitoring system. Through simulations, we show that PECAN meets the server upload bandwidth constraint, and achieves the fairness well at each peer. We finally verify that the control overhead in PECAN caused by the search, reputation, and monitoring systems is very small, which is an important factor for real deployment.

• The KIPS Transactions:PartA
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• v.14A no.7
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• pp.451-456
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• 2007

In this paper, we regard computer systems as heterogeneous multi-server systems and propose a cumulative fair scheduling scheme that pursues long-term fairness. GPS(generalized processor sharing)-based scheduling algorithms, which are usually employed in single-server systems, distribute available capacity in an instantaneous manner. However, applying them to heterogeneous multi-server systems may cause unfairness, since they may not prevent the accumulation of scheduling delays and the extra capacities are distributed in an instantaneous manner. In our scheme, long-term fairness is pursued by proper distribution of extra capacities while guaranteeing reserved capacities. A reference capacity model to determine the ideal progresses of applications is derived from long-term observations, and the scheduler makes the applications gradually follow the ideal progresses while guaranteeing their reserved capacities. A heuristic scheduling algorithm is proposed and the scheme is examined by simulation.