Читать книгу Fog Computing - Группа авторов - Страница 59

The complexity of the MFC topology, which encompasses the hierarchical, vertical, and horizontal interconnections among the cloud, the iFog, the mFog, and the end-devices, has increased the challenges in system design and validation. Commonly, the developers of the distributed computing system, such as cloud services, pervasive services, or mobile services, have a broad range of simulation options (e.g. CloudSim [http://www.cloudbus.org/cloudsim], the ONE simulator [https://www.netlab.tkk.fi/tutkimus/dtn/theone], and iFogSim [https://github.com/Cloudslab/iFogSim], etc.) to validate their system designs. However, existing simulation tools are insufficient to validate many MFC systems because they are unable to address all the elements of MFC. For example, although the cloud service–based simulation tools are capable of simulating the hardware heterogeneity, they do not include mobility-related factors. For another example, while the mobile service-based simulation tools are capable of simulating the movement of entities, they do not have corresponding mechanisms to simulate the complete MFC network that contains the hierarchical and the vertical interconnection among the entities. Finally, iFogSim is capable of simulating the stationary fog nodes but it does not provide the mechanism to simulate the mobile fog nodes. Consequently, integrating the existing tools to develop a comprehensive MFC testbed becomes a critical challenge.