Session-Level and Network-Level SLA Structures and VoIP Service Policy over DiffServ-Based MPLS Networks

This paper proposes a framework for session-level SLA (Service Level Agreement) and network-level SLA management to provide QoS-oriented application services over DiffServ/MPLS networks. DiffServ and MPLS technologies enhance the capability of QoS guarantee on IP network, and application service provider can provide QoS-oriented application services to their customers based on the transport networks. The example of using our approaches in the VoIP service involving the network service provider, the VoIP service provider, and the VoIP customers are examined. The session-level SLA between VoIP service provider and VoIP customer and the network-level SLA (N-SLA) between network provider and VoIP service provider are constructed in this paper. Besides, the VoIP service provider faces the QoS-mapping issue and the balance between revenue and cost, i.e., how to contract the N-SLA. Therefore, we introduce an off-line SLA evaluation scheme, a heuristic optimization algorithm and an on-line SLA process method to provide VoIP service policy, and then the optimal QoS-mapping can be resolved. The concept of this framework of session-level SLA and network-level SLA management can be extended easily into other real-time multimedia and non-real time data services. key words: SLA, QoS management, service policy, VoIP, MPLS, DiffServ