• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.3
• /
• pp.843-871
• /
• 2015

Cloud computing evolve as a cost effective business model for IT companies to focus on their core business without perturbing on infrastructure related issues. Hence, major IT firms and Small & Medium Enterprises (SME) are adopting cloud services on rental basis from cloud providers. Cloud Service level agreements (SLA) act as a key liaison between consumers and providers on renting Anything as a Service (AaaS). Design of such an agreement must aim for greater profit to providers as well as assured availability of services to consumers. However in reality, cloud SLA is not satisfying the parties involved because of its inherent complex nature and issues. Also currently most of the agreements are unilateral to favour the provider. This study focuses on comprehensive, 360-degree survey on different aspects of the cloud service agreements. We detailed the life cycle of SLA based on negotiation, different types of SLA, current standards, languages & characteristics, metrics and issues involved in it. This study will help the cloud actors to understand and evaluate the agreements and to make firm decision on negotiation. The need for standardized, bilateral, semantic SLA has also been proposed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.10
• /
• pp.2715-2720
• /
• 2009

Supporting Quality of Service (QoS) for multimedia services in heterogeneous mobile networks is a part of key issue for Three Generation Evolution (3GE) development. A QoS management structure needs to guarantee the QoS of moving users based on an end-to-end negotiation to support the seamless service when MT is moving between the heterogeneous networks. We propose an end-to-end negotiation method based on SLA(Service Level Agreement). For this aim, the SLA control and algorithm for supporting MT's QoS is considered. Simulation is focused on the average delay and packet loss rate, and the results show that our proposed method provides mobile terminals with the optimal performance.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06a
• /
• pp.239-241
• /
• 2012

최근 클라우드 서비스 공급자들은 세계적으로 증가하는 고객의 수요에 대응하기 위하여, 다양한 지역에 데이터센터들을 구축하고 시스템의 규모를 확장시키고 있다. 클라우드는 통합된 자원을 이용하기 때문에 부하 분산(load balancing)을 통해서 시스템의 성능 및 안정성을 향상시킬 수 있다. 하지만 지역적으로 분산된 데이터센터들을 운영하는 클라우드 컴퓨팅 환경에서는 자원 부하의 분산과 서비스 응답 속도(service response time) 사이의 상관 관계를 고려할 필요가 있다. 그럼에도 불구하고 대부분의 클라우드 서비스 공급자들은 고정된 최소 서비스 응답 속도를 서비스 수준 협약(SLA: Service-Level Agreements)을 제시하고 있는 현실이다. 이와 같이 SLA에 최소 서비스 응답 속도를 임의로 고정할 경우, 거리차이가 있는 데이터센터(SLA에 명시된 응답 속도 보다 느린 데이터센터)에는 부하가 분산되기 어렵다. 따라서 지역적으로 분산된 데이터센터 환경에서는 응답 속도에 대한 가변 SLA를 적용할 필요가 있다. 본 연구에서는 지역적으로 분산된 데이터센터를 운영하는 클라우드 컴퓨팅 환경에서 가변 응답 속도를 적용하기 위한 방법으로써 서비스 응답 속도와 가격을 고려한 자동화된 SLA 협상 메커니즘을 적용하고 그 유효성을 평가하였다. 시뮬레이션을 이용한 실험 결과를 통해서 SLA 협상을 통한 가변 SLA를 이용하는 방법이 고정된 SLA를 이용하는 방법에 비해서 더 높은 SLA 보장률을 지원하고 클라우드 공급자에게 더 높은 수익을 제공함을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.05a
• /
• pp.171-174
• /
• 2013

Virtualization technology opened a new era in the field of Data intensive, Grid and Cloud Computing. Today's Data centers are smarter than ever leveraging the Virtualization technology. In response to that, Dynamic consolidations of Virtual Machines (VMs) allow efficient resource management by live migration of VMs in the hosts. Moreover, each client typically has a service level agreement (SLA), leads to stipulation in dealing with energy-performance trade-off as aggressive consolidation may lead to performance degradation beyond the negotiation. In this paper we propose a Cloud Based CDN approach for allocation of VM that aims to maximize the client-level SLA. Our experiment result demonstrates significant enhancement of SLA at certain level.

• Journal of KIISE
• /
• v.42 no.11
• /
• pp.1361-1371
• /
• 2015

Depending on the increase amongst various cloud services, the technology of the Cloud Service Broker (CSB) to find the most appropriate services to meet the needs of cloud service consumers has emerged. In order to advance for cloud services to be used through the CSB, it is important to ensure the quality level that meets the demands of consumers through a negotiation process based on the Service Level Agreement (SLA). However, quality metrics of cloud services are different from each other based on the measurement scale, which represents the quality level, and the calculation for each type of cloud services. Therefore, it is necessary to analyze the variability of the quality of cloud services and establish a SLA model for ensuring and improving the level of quality. In this paper, we analyze the quality metrics for the specific type of cloud services by applying the cross-cutting concept and propose a Virtual SLA (VSLA) meta-model.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.8
• /
• pp.1825-1842
• /
• 2013

Rapid growth of the IT industry has led to significant energy consumption in the last decade. Data centers swallow an enormous amount of electrical energy and have high operating costs and carbon dioxide excretions. In response to this, the dynamic consolidation of virtual machines (VMs) allows for efficient resource management and reduces power consumption through the live migration of VMs in the hosts. Moreover, each client typically has a service level agreement (SLA), this leads to stipulations in dealing with energy-performance trade-offs, as aggressive consolidation may lead to performance degradation beyond the negotiation. In this paper we propose a heuristic based resource allocation of VM selection and a VM allocation approach that aims to minimize the total energy consumption and operating costs while meeting the client-level SLA. Our experiment results demonstrate significant enhancements in cloud providers' profit and energy savings while improving the SLA at a certain level.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.4A
• /
• pp.380-387
• /
• 2011

While mobile IPTV services are supported through the mobile WiMAX networks, there must need some guaranteed bandwidth for the IPTV services especially if IPTV and non-IPTV services are simultaneously supported by the mobile WiMAX networks. The quality of an IPTV service definitely depends on the allocated bandwidth for that channel. However, due to the high quality IPTV services and to support of huge non-IPTV traffic over mobile WiMAX networks, it is not possible to guarantee the sufficient amount of the limited mobile WiMAX bandwidth for the mobile IPTV services every time. A Service Level Agreement (SLA) between the mobile IPTV service provider and mobile WiMAX network operator to reserve sufficient bandwidth for the IPTV calls can increase the satisfaction level of the mobile IPTV users. In this paper, we propose a SLA negotiation procedure for mobile IPTV users over mobile WiMAX networks. The Bandwidth Broker controls the allocated bandwidth for IPTV and non-IPTV users. The proposed dynamically reserved bandwidth for the IPTV services increases the IPTV user's satisfaction level. The simulation results state that, our proposed scheme is able to provide better user satisfaction level for the IPTV users.

• The Journal of Society for e-Business Studies
• /
• v.12 no.2
• /
• pp.135-153
• /
• 2007

As a system integration framework, the role of SOA(Service Oriented Architecture) is widening and increasing day by day. The SOA framework enables software applications or computing resources to integrate flexibly and to provide more various business models. But, it is strongly required of SOA service level management for applying SOA in real business world. In this respect, we need a study on method for managing SOA system for keeping higher quality of SOA. This paper provides a new management method for SOA service level by analyzing quality factors in Web services, as SOA implementation, and negotiation/contract according to SLA methodology.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.4B
• /
• pp.444-454
• /
• 2004

To support diverse transmission requirements of multimedia applications, Quality of Service (QoS) should be provided in the Internet, where only the best-effort service is available. In this paper, we describe our recent effort on the implementation and verification of an extendable and flexible QoS allocation and resource management system based on the bandwidth broker model for realizing the IETF differentiated service (DiffServ). Focusing on the bandwidth issue over single administrative domain, the implemented system provides real-time resource reservation and allocation, delayed call admission control, simple QoS negotiation between sewer and users, and simple resource monitoring. The implemented system is verified by evaluating the performance of a resource-intensive application over the real-world testbed network.