y, a software tool that is used in the operational cloud to test the resiliency and recoverability of their Amazon Web Services (Tseitlin, 2012). Telecommunications applications can be highly complex with many failure modes. Approaches that combine the benefits of Chaos Monkey style testing and more traditional stability testing would be very valuable. 2. Mitigating the effects of planned outages. VFs need to be able to accommodate long planned outages. It can be costly to add additional levels of replication as a guard against Building the Network of the Future Impact of Redundancy on Reliability + Alternate DNS-RVIP 99.99999% (in DPMs) 2 Site 99.99990% Geo-redundancy (<1 sec failover) Query retries (in DPMs) 99.99900% 99.99000% 99.90000% No local redundancy Local Redundancy Single Site 99.00000% FIGURE 5.15 Resiliency features and impact on resiliency. planned outages. With ONAP, there is the possibility to use automation to migrate VFs to locations that are not subject to the planned outage. Designing reliable and efficient tech- niques for migration is an area that deserves further investigation. 3. Accurate fault identification. The multilayer distributed nature of NFV architectures means that accurate and timely fault detection can be a challenge. Without accurate and timely fault detection, achieving high availability is impossible. Understanding what types of metrics need to be collected and how to process and correlate the metrics to detect and isolate faults is essential. There are many opportunities to apply advanced analytics tech- niques such as machine learning to improve fault detection. 4. Automated failure recovery. Failures are more frequent when using commodity hardware and software. Therefore, it is essential to handle them more efficiently by using automated failure detection and recovery. Procedures for automated detection and recovery represent a major opportunity to improve VF availability. 5. Software robustness. Applications designs that are insensitive to short failures and fluctua- tio