The Research Of Key Technology On Policy-Based Service Level Agreement Management System

With the development of informationization and network application of our society, the telecommunications market has become increasingly open and flexible, and more businesses supply users with different levels of value-increased service to meet various needs, which will enhance their competitiveness, and increase the profits. However, the emergence of SLA has guaranteed efficient services for users, and therefore, the service providers have attracted a large amout of loyal and stable users, thus gained competitive advantages.At present, much work has been done in the research of SLA by international standard organizations, such as TMF, ITU. But in the SLA only network performance indicators are used to evaluate the quality of service, which can not directly reflect the customers'satisfication on service, so it needs perfection in the aspect of the customers. Moreover, the majority of networks still use static SLA, which cannot adapt to the external conditions like network status, so the dynamic network makes it necessary to realize the dynamic SLA.Therefore, the SLAM studied in this paper is performance indicators based on QoS evaluation, and is aimed to achieve guaranteed customer-centric services; also the policy is brought into the SLAM system to construct a policy-based SLAM prototype system. The SLA management function modules are divided into the following four layers in this paper: application, business, network and policy supplier layer which provides policy for other three layers throughout the whole process of SLA management. The application of policy used in SLAM can effectively deploy service in dynamic circumstances, including network resource, the mutative service element and develop the uniform source information model to represent different service module interfaces. Accordingly, we can separate the logic policy and the modules, reduce the coupling between application and circumstance and make SLAM system more flexible, universal and extendable. SLA indicators are key ones to evaluate the quality of services; users'various levels of requirements are satisfied by showing the characteristics. The wide range of business, the diversification of the types of customers and the complexity of implementing the technology, will bring a different impact of evaluation indicators. So this paper established a unified evaluation model from the services/technology-related perspective, indicators level perspective, statistical perspective and business services classification perspective. These four dimensions quantize the service for more effective communication with customers. In order to improve the efficiency of the development of SLA parameters, to enhance the reusability of the template, the development method which based on the succession of SLA indicators system is presented in this paper. First, based on NGN's three-triple services (voice, video and data) and then distinguished by the interaction and the sensitivity of real-time business, finally business succession system is established. Secondly, indicators could be developed on each level based on the affair baseline and the service topology:extract the commonness of the services in the root to develop services unrelated indicators; developed in all types of the basic business of the timeliness of business and quality of business-related indicators; for specific examples of service developed service-related indicators with its'characteristics. Finally all the criterions are gathered in the DFS path from root to any specific service node as its indicator set. Index system, based on the service succession, greatly reduces the development steps of the indicators, has a great value in application for the development of the SP's new business and can be better adapted to the technical and business development.SLAM system should ensure the quality of end-to-end services. Monitoring and assessing in the implementation of the SLA are important parts, through which SP can verify its quality of the services and control the services to satisfy the SLA and guide to model on the SLA. Customers can also clearly know whether they have been stipulated in the SLA contract service levels. Thus, the policy-based dynamic assessment mechanism is proposed in this paper to externally evaluate the current service by establishing dynamic mapping between PKQI, and SKQIand KPI and Counters (generally refer to the original measurement datas). During this process, according to the dynamic factor analysis, four policies are established: monitoring policy, mapping policy, reporting policy and threshold policy.Based on service types, levels and specific content, as well as the types of customers, service providers select different parameters and set different threshold value for them, make different mapping function, and thus generate grading mapping method. Moreover, according to the site, time, user roles, network status, develop mapping policy under different states and different perspectives, which create the dynamic mapping relations between the customer perceived indicators and network performance indicators, and enhance the purely calculate of a function to the choice of mapping methods. Moreover, in the assessing process, policy can guide the parameter detecting, periodically evaluating based on obedience degree and report generation, thereby dynamically output quantitative indicators of the quality of business.Correspondingly, the diversity service and test for obedience degree are provided to implement the dynamic SLA management.This paper develops a prototype system of SLAM, and achieves a policy-based dynamic evaluation which has been applied on IPTV. Because the IPTV requires far greater resource than other business services and it is sensitive on the evaluation parameters. The IPTV's performance always changes along with the network and time, so the study of SLAM applied into IPTV is representative and universal and also accumulates experience to guide other business SLA research.The testing results show that using policy in the SLAM system makes the SLA management more flexible, timely and effective. It can evaluate the quality of current service by choosing appropriate policies automatically, according to the network status and space-time dimensionality. And it also can use the existing network resources adequately and reasonably without the service providers'intervention. And what's more, it can support the evaluation of Multi-Service's quality.