TABLE OF CONTENTS In this section, we focus on defining a service model that provides a framework for solving the service assurance problem. Our presentation will follow the work of [6], which is influenced by some of the earlier work of the Internet service model, the MNG, and various root-cause analysis approaches.
Our approach is analytical in nature and starts with a graph-structure representation of a service. The graph structure is hierarchical and captures the essence of important relationships between service components and customer needs. In addition, the graph structure also facilitates the implementation of many assurance algorithms. With the graph structure defined, the next step is to identify the service components in a systematic manner. We suggest performing an analytical decomposition of a service to identify the critical subservices. Subservices are further broken down into other lower-layer subservices, including network and physical components. To create a service model, all the components need to be instantiated, which means that the service model is logically associated with the real network and relevant assurance data can be fed into the model. The real value of a service model will best be illustrated with a set of assurance OSS functions. Thus, we will next describe a set of assurance-related tools in conjunction with the service model and discuss how these tools can be used to solve various service assurance problems. The rationale for the assurance tools will be described in the context of some theoretical algorithms that rely on some...
