A solution for goal-oriented policy refinement in NFV manegement and orchestration systems

Abstract

Some studies are tackling the integration of Network Function Virtualization (NFV) and Software-Defined Networking (SDN) in different environments (e.g., Cloud Computing and Wide Area Network). The use of NFV technology, along with SDN, will play a significant role in 5G networks, since they allow the network programmability and the fast delivery of new services. Although NFV/SDN architectures have clear potential benefits, they are still at an early stage of development. One of the main challenges is the definition of high-level policies necessary to simplify the configuration of NFV Management and Orchestration (NFV-MANO) operations, such as resource allocation and optimization mechanisms, and to meet the customers’ requirements. In this thesis, we intend to tackle part of this problem, namely, issues in the policy refinement procedures. We present the problem for the creation of a policy refinement procedure for NFV systems, as well as the requirements that we consider necessary for their composition. In this sense, we point out the need to have an approach that provides a functional solution for automated policy refinement in policy-based NFV management and orchestration systems. Such a method must support several features such as goal-oriented refinement and detection and resolution of policy conflicts. In this context, we propose the AuTomated POlicy Refinement SysteM for NFV (ATOM), an automated solution for the policy refinement process for Policy-Based Management Systems (PBM) in NFV scenarios (NFV-PBM). To achieve its goal, the ATOM comprises 3 functional blocks: NSChecker, NSPlanner, and Feedback Module. The NSChecker is a semantic verification system to find inconsistencies among policies defined in NS Request (NS-Req) and global policies previously created in the NFVI, i.e., application-specific policies. The NSPlanner provides a solution that enables NFV-MANO to record high-level goals extracted from Network Service Descriptor (NSD) and perform a fully automated policy refinement, that derives enforceable policies (Event-Condition-Action or ECA rules) to govern NFV-MANO behavioral choices while satisfying the goals. Besides, NSPlanner performs policy analysis between management-specific policies, i.e., rules that will be generated by the refinement process and stored in NFV-PBM to govern system behavior. Finally, the Feedback Module is a monitoring system that aims to assist the operator in the task of verifying if the enforceable policies are fulfilling the high-level goals. We conducted a performance evaluation of both NSChecker and NSPlanner. The results demonstrate that NSChecker is efficient even in scenarios with 50,000 NFV Infrastructure Nodes (NFVI-Nodes), while NSPlanner is efficient even in scenarios with 1000 goals and 1000 alarms pre-registered.