 rates. A standard approach for rep- resenting defects for systems that process significant volumes of transactions is to use defects per million (DPM) transactions. 16.9.3 VNF RESILIENCY REPORTING The ability to measure VNF resiliency and assess the ability of the cloud platform to adapt and recover from any disruption, is a critical function for service operators. Since every VNF may have Network Measurements a different target for availability, its underlying resiliency design may also vary. There are several characteristics of resiliency behavior that can be assessed by measurements: Seamlessness: Measuring service continuity or seamlessness, requires measuring impact to end users when a VNF is impaired. Service continuity objective is defined as an unin- terrupted user experience even when an anomaly event occurs. If the duration of VNF impairment (including failure event, detection, and fail over recovery) is not perceptible to the user, then it can be characterized as seamless service continuity. Robustness: Measuring robustness can be accomplished by assessing the availability of additional capacity and a wider range of accessible resources in the infrastructure. Topological transparency contributes to higher resiliency; with less topological constraints comes less limitation to finding available resources minimizing the impact from physical failures, or electrical or network outages. Uniformity: Measuring uniformity requires distributed measurements of performance and comparing VNF performance across different cloud zones and locations. When a ser- vice is provided by more than a VNF distributed across multiple VMs and locations, ser- vice requests to those VNFs may be imbalanced and drive varying resource constraints. Uniform performance can be achieved by ensuring service requests are distributed and load balanced. This reduces risk of resource scarcity, which enables higher VNF resiliency. Virtual function resiliency covers both reliability and performance. Typical reliability measure- ments for VNF r