s it possible to scale out across sites and regions instead of scaling up in a single location. Scaling out results in significantly lower costs and higher availability. To meet the reliability demands of a carrier grade network, the AIC infrastructure management (IM) domain manages all interzonal networking. IM ties all nodes, LCP systems and applications, hypervi- sors, and software-defined networking (SDN)-local agents together, irrespective of their location or connectivity, into a single management plane with uniform security and access to other networks. Chapter 5 discusses various architectures for achieving availability targets. 4.4.2 FAULT TOLERANCE Many organizations and enterprises want "cloud-native" VNFs, operations support systems (OSS), and business support systems (BSS). Cloud-native is a term that describes the design of systems and appli- cations specifically for the cloud. These applications can realize numerous benefits that are enabled by the cloud environment, including improved reliability of service, simplified IT management, and strategic advantages related to service delivery. In fact, cloud-native applications are the driving force behind an organization's ability to serve customers globally, operate at an industry leading cost struc- ture, and deliver an effortless customer experience. What is essential to understand about cloud-native applications is that they are built to expect failure. This concept introduces the need for fault tolerance. Fault tolerance is what enables a system to continue its intended processes when some part of the system fails. At the point that an application or the infrastructure fails, the fault tolerance strategy and network design minimizes the impact of the failure by sharing the workloads across sites to achieve improved reliability (see Figure 4.5). The fault tolerance strategy revolves around two key components-"infrastructure resiliency" and "application resiliency." These two components are the defining features of any AIC fault- tolerant building bl