Читать книгу Fog Computing - Группа авторов - Страница 48

Operating fog servers can be costly for the providers especially when the providers are unable to identify what tenants really demand. For example, stream data filtering is a common method used in fog computing and the corresponding program can be quite simple in comparison to the scientific programs operated on the cloud. However, in the classic approach, the tenant may need to wrap the simple program to a package that runs on the resource-intensive VM environment because the provider was following the classic cloud service deployment approach to providing the fog server. Explicitly, the provider has inefficiently increased the burden of the fog node while providing excess service to tenants who demanded only a simple method. Therefore, the provider should consider what are the most cost-efficient service types that should be supported by the fog servers. Beside the service type, the providers of the battery-powered mobile fog nodes need to specifically address the energy-efficient of the fog servers in order to improve their sustainability. For instance, although providers can easily replace UAV-Fog nodes, considering the extra latency derived from the process/task handover and migration while replacing the UAV-Fog nodes, frequently replacing UAV-Fog nodes will reduce the QoE for the tenant-side clients.