The Research Of Layered SLA Technology Based On Cross-domain

With the continuous expansion of network application, the telecommunications market has become increasingly open and flexible. The telecommunication's monopolization has gradually been broken, the competition among operators is getting tougher and the customers' requirement for service quality is getting higher. Therefore how to take the initiative in serving people to attract and obtain their loyalty is the focus point of competitive strength among operators. Service Level Agreement (SLA), a service agreement about the level of the service quality established between Service Provider and Customer or between Providers, can profit both Service Providers and Customers. Service Providers can supply customers with different levels of products and services to meet various requirements, which can enhance their competitiveness and increase the profit. More and more Service Providers will supply SLA for Customers.At present, much work has been done in the research of SLA by International Standards Organizations, such as ITU, TMF. It discussed the management methods and basic organizational framework and expression ways of SLA. But the research has not systematically expounded the SLA's architecture, especially the co-existing of Network Providers, Content Providers, Service Providers and Customers these four parts under existing network management model, the advanced research of SLA's architecture and relative management technology under multiple administrative domains is necessary.The main research content of this paper is layered SLA technology based on cross-domain, mainly including cross-domain SLA management and key technology of layered SLA.SLA indicators, the core parts of the SLA, are essentially used to evaluate the quality of services. The measurement process of service level equals to the evaluation process of SLA indicators to determine whether or not the indicators meet the rated threshold. Considering the different characteristics in different services and mapping relationship among these indicators, this paper establishes a four-dimensional model of the SLA indicators, which is used to characterize parameter's property from the perspective of parameter types, parameter layers, service opinions and service classification. The four-dimensional model assists Service Providers in parameters classification and management from multiple dimensions. Then we have a discussion from perspective of parameters stratification to establish a general method of the development of SLA parameters. In the process of parameters development, on the one hand we should analyze the different levels of concern in service performance from customer, SP, NP, and other different roles, on the other hand we should analyze the self-characteristics of the service. We obtain PKQI and SKQI through the respective analysis of service usage scenarios and basic scenarios, and decompose the SKQI into KPI from the analysis of service flow and network topology, then we do correlation test of interlayer parameters until the integrity of SLA parameters system. This method shows its strong operability and versatility, and the designed parameters are comprehensive and much more targeted as the focus consideration of different roles.After building a layered parameter system, the following research is focused on the parameter mapping between layers. The mapping from KQI to KPI is called Configuration mapping, while the mapping from KPI to KQI is named Assessment mapping. We propose an improved warning method that is based on the layered SLA technology because of some existing problems in current warning method in Assessment mapping, such as high expense, high false alarm rate, and unobvious warning effect. The method firstly makes an early warning judgment to the KPI layer and filters out the normal KPIs to avoid the upward assessment mapping, on this way it greatly reduces the monitoring workload, lowers computational cost and improves the efficiency of SLA management system. And the assessment mapping of the abnormal KPIs enhance the reliability of the system. Besides, the speed element of the SLA performance descend is taken into consideration when using trend judgment to the KQI layer. A pre-warning of the fast speed decline is made to enlarge the interference time for SP to reduce the rate of violation. As for the study of collocated mapping, a method of using the known assessment mapping to set the parameter collocated mapping district is described. This method can guide SP to set the parameter collocated mapping district efficiently. The method takes the evaluation of mapping as a basis and realizes the calculation from KPI to KQI through the existed evaluation formula. A function taking the KQI as independent variable and questioning the value of KPI could be gained through the interpolating process. This function can be seen as an approximate function of the inverse function of the assessment function. Through this function, the corresponding KPI value can be gained by inputting the KQI value. Because the function gained through interpolating is just an approximate one, the KPI value should be corrected through the iteration approximation method. Under existing network model, end-to-end QoS is guaranteed by the cooperation of Customer, SP, CP, NP. The end-to-end SLA model includes kernel mode, cascade mode and mixed mode, with each mode having its own SLA operation and negotiation process. We give a SLA mapping mechanism based on cross-domain because of the traditional method's shortcoming, such as the limitation of negotiation granularity, the requirement of the same perception for negotiated objects and unachievable. The cross-domain based mapping mechanism has corresponding relation among the parameters on the same layer for SLAs, except the mapping relation between two layers in a SLA. The negotiation can be done on every layer which make negotiation be more efficient and lower the standard of negotiation technology, and will be beneficial to fault diagnose and quality monitoring.A new express of SLA is needed to support the auto-maintenance, auto-test and negotiation of the SLA because SLA is widely spread and the operation and monitoring of SLA becomes more and more complicated. This paper presents a framework of SLA language and analyzes it in the aspects of expressing context, form and operation mechanism with instance on the cross-domain negotiation application.In the end, on the basis of the above-mentioned theories, we develop a SLA quality monitoring environment based on TS layer taking IPTV for example, and achieve some parameters'monitoring, and then realize the comprehensive evaluation and fault diagnose further.