TheFog layer consists of various equipment and nodes. Datacenters are one of themain components. Even a classic and enormous Datacenter can be placed in theFog layer if it is closer to the abstraction layer than the Cloud environment.For easier detection, first, we clarify Datacenter types that lie on Fog layer.The definition of classic datacenters is clear, sets of servers and hosts thatprovide services through virtualization and resource allocation techniques.
Mini Datacenters are just a set of servers which, in terms of size and power,can be equal to a small part of the commonly used Datacenters. The main pitfallthat caused the writing of this section is the inappropriate use of the termsMicro and Nano Datacenters. Micro Datacenters as previously mentioned, areoften a resource-rich stand-alone server or host that is capable of offeringvarious services. On the other hand, Nano Datacenters are usually a capable SBCor tiny device that can provide proper communication, processing, and storageservices. The last two terms are mistakenly replaced with each other and theabove explanation tries to categorize them according to their features.Inthe following, first, we aimed to introduce Fog Nano Datacenters attributes andexplain them. Obviously, the high variety of Fog Nano Datacenters makes itdifficult to explain all the features, therefore; we can only cover the basicand essential features. Next, we make a comparison between Micro and NanoDatacenters.
Last, we will check features on different Fog Nano Datacenters.· Energy and operationalcost efficiency: These devices are tiny and need to consume little energy.Many of these Fog Nano Datacenters operate through batteries rather thandirectly connect to the wall outlets. Considering the importance and necessityof their continuous operation in many applications, energy efficiency andlow-cost performance are two vital factors.
For example, Fog Nano Datacenterslike Raspberry Pi, BeagleBoard and Intel Edison can operate with 5 volts and 2amps which can be obtained from the power banks or batteries quite easily.These devices are remarkably cheap and have adequate resources for manyapplications. · Mobility: One of themost important shortcomings in Cloud Computing was the mobility issue that FogComputing attempted to answer it. By using Fog Computing in applications thatmobility is crucial like Vehicular ad hoc networks (VANETs) or SmartTransportation, communications between cars and infrastructures become moreaccurate and responsive. Fog Nano Datacenters makes mobility even morereachable. These are small and lightweight devices that make it easier to movearound.
Some devices, such as Smartwatches and phones are naturally fitted bypeople but, other equipment can be moved through robotics and drones.· Scalability:Interoperability for Fog Nano Datacenters can help to make this featurefeasible. By adding interoperability, the variety of equipment is no longer aproblem and we can scale heterogeneous environments in different forms withoutmuch difficulty. Actually, these devicescan provide services for various applications, from a smart room to a largeshopping mall or industrial factory. Scalability can have a direct impact oncoverage, network dimensions and equipment densities. · Distribution: Foglayer has a distributed architecture that sits between perception and corelayer.
In contrary, Cloud Computing has a centralized architecture and allrequests are sent to a specific point. This may cause a bottleneck which leadsto congestion, low availability and accessibility. Fog Nano Datacenters areactually tiny Fog nodes that build up a huge portion of this technology. Theyare distributed in Fog layer and consist of heterogeneous devices. Applicants’requests can be segmented and answered through multiple devices.· Resource allocation: Toachieve the ideal level of efficiency, Fog Nano Datacenters should be able toprovide required services.
In general, this includes processing, storage andcommunication services. Network interoperability is one of the most importantcommunication services. Of course there, are other optional services like:Monitoring, Analysis, Resource Management, Data Virtualization/Standardizationand VM Scheduling.
Deploying and providing these features are mainly related tosystem’s goals and availability of resources. At the end, it should not beforgotten that the purpose of these Fog Micro Datacenters is not to processheavy operations, but rather to provide services for temporary and transienttasks. · Nano Size:Dimensions and weight of devices are important. These devices should belightweight so can easily be moved. In the mobility scenarios (Human, aerialand robotics) this feature is a decisive factor. Also, small dimensions allowthem to be easily applied and run.· Heterogeneity: The varieties of nodes thatcan operate as Fog Nano Datacenter are very high and still increasing.
Thisincludes hardware, software and architectural features. This heterogeneity isreally helpful for end users because it provides a higher level of flexibilityfor things communications. In heterogeneous environments interoperability isreally crucial and hides differences.
Inthe following, first Table.2 demonstrates a comparison between Micro and NanoDatacenters then, in Table.3 it shows some detail information about previously mentionedFog Nano Datacenters.