QoS policy verification for DiffServ networks

Abstract

Configuring routers and network devices to achieve quality of service (QoS) goals is a challenging task. In a DiffServ environment, traffic flows are assigned specific classes of service, and service level agreements (SLA) are enforced at routers within the domain. We present a model for QoS policy configurations that facilitates efficient property-based verification. Network configuration is given as a set of policies governing each device. The model efficiently checks the SLA against the current configuration using computation tree logic model checking. By following possible decision paths for a specific flow from source to destination, properties can be checked at each hop, and assessments can be made on how well configurations adhere to the specified agreement. The model also covers configuration debugging given a specific QoS violation.