Active versus passive assurance – are both needed, and why?


      The adoption of network functions virtualization (NFV) and software-defined networking (SDN) technology into the networks of communications service providers (CSPs) has created a new paradigm for creating and managing services. Direct customer control of services being used along with a DevOps model for new service creation are challenging the way CSPs look at service assurance. It’s no longer just a tool used to manage high-revenue SLA based services: service assurance must become an embedded function of every service, in order to provide systems with a complete overview of virtual networks.

      Service assurance relies on network and service level key performance indicators (KPIs) and key quality indicators (KQIs) to understand how networks or services are performing. Like in traditional networks, these KPIs and KQIs are derived from either active or passive probes, except that in the virtual or hybrid network, these probes are implemented in the software layer, as virtualized network functions (VNFs), rather than in purpose-built hardware.

      Active probing provides a horizontal perspective of networks and services, and is ideally suited to real-time, end-to-end service metrics. Passive probing, on the other hand, provides a vertical perspective of networks and services, and is ideally suited to generate large volumes of historical performance data at specific locations within the network. In the white paper entitled The critical role of active assurance in the context of SDN and NFV, EXFO explores the role of both active and passive probing in virtual or hybrid networks. The paper specifically addresses the way they relate to active assurance of customer quality of experience (QoE), as well as real-time, multi-dimensional analytics for automation of SDN and NFV orchestration.