llite, Voice over Internet Protocol (VoIP), and Signaling System 7 service provid- ers. Communications providers must also report information regarding communications disruptions affecting Enhanced 9-1-1 facilities and airports that meet the thresholds in the FCC's rules. Detailed best practices for maintaining network continuity have been developed,* and switching, transport, and http://www.corp.att.com/ndr/pdf/cpi_5181.pdf Building the Network of the Future network infrastructures have been designed to meet these very stringent requirements. High avail- ability has been attained using custom hardware, fault-tolerant software design, and extensive testing to ensure that the production software has few defects (Giloth, 1987). Excellent examples of highly reliable designs date back to digital switching systems such as the 4ESS (K. E. Martersteck, 1981) and 5ESS (Martersteck and Spencer, 1985), and networks have been designed with survivability as a core objective (Wu, 1992; Krishnan, 1994; Choudhury, 2004; Klincewicz, 2013; Ramesh Govindan, 2016). As the industry evolved to IP and Voice over IP technologies, switches and routers continued to be designed with specialized hardware and software that allowed them to continue to meet "carrier grade availability" requirements (Johnson, 2004). The introduction of network functions virtualization (NFV), combined with the deployment of network functions on cloud-based platforms, has had a dis- ruptive impact on traditional high availability hardware-based solutions. With NFV, failure of an indi- vidual hardware element may have little or no impact on service availability since virtualized network functions can be quickly (even automatically) restarted on spare cloud hardware, often within seconds or minutes. NFV is leading to significant changes in the way traditional vendor resiliency requirements are defined, measured, monitored, and managed (Rackspace, 2015). Some requirements that made sense in the traditional monolithic environment no longer apply, while others need t