ute capacity at the edge when it is needed may lead to the service expectations of cus- tomers being missed. This leads to a tradeoff between the risk of not meeting the SLA and the cost of building and operating a network to satisfy it. In any case operators will need to deal with new KPIs, that is, cell edge compute resources, in their cell site planning and need to explore new parameters to measure customer satis- faction and resource usage. At least initially, operators are likely to use simple heuristic rules to provision compute services, by deploying small scale and upgrading resources whenever a certain benchmark exceeds a specified demand. 7.3.2.3 Reliability Considerations Another important criterion for 5G deployments is reliability, which in itself is not new; however, different 5G use cases require different reliability levels. For example, in Wave deployments supporting high throughputs, it is important to achieve a certain degree of reliability on par with that of lower frequencies (which is of the order of 99.99%) to provide consistent high average throughputs to users. For ultra-reliable low latency use cases, the reliability requirements may be even higher, for example, in the case of mission-critical applications. In the past, the core network was the primary source of an operator's concern in reliability considerations. Failures in core network elements may cause considerable user and service impacts as they can affect large areas (and even potentially the whole network), while a failure in a single RAN cell site may only have a geographically isolated impact. In 5G, at least with some mission-critical IoT services, RAN failures will be harder to tolerate. Furthermore, in addition to radio reliability considerations, which are well under- stood from previous generations of cellular deployments and have been properly addressed by NR design, there are additional factors related, for example, to compute resources relia- bility. That is because NG-RAN may be virtualized (see Section 6.2) and may p