As you can see in the picture above (Fig.2), the access layer is the domain in which edge technologies are located. Our research focuses on Nano Datacenters and interoperability. This paper is organized as follow. Next section (Sec. 2) provides a brief overview of the related studies. Sections 3 discuss features and characteristics of Fog Nano Datacenter followed by Section 4 which describes QoS fundamentals and how much Nano Datacenter can support them. Section 5 is devoted to Communication protocols and their attributes. In section 6, we review a number of Application protocols and compared them based on different features. Next section (Sec. 7) introduces a few Interoperability technologies. Lastly, we discuss few challenges and issues in Section 8 and conclude this paper in Section 9.
3) Literature Review
Edge Datacenters were leveraged by the cloud to meet interactive application and services demands on lower latency and energy consumption. 1 Present a method for migration from cloud to the clients by edge/ fog resources in form of Micro Datacenters. 2 Considered a distributed cloud system including geographical distributed Micro Data Center in a large number, over different locations next to mobile devices to reduce bandwidth costs and increase high-availability. They also provide a MDC – based model, with high connectivity, logical network abstraction as a part of wellness application. The management framework reveals topology, performance and fault information in a static manner. The role of Fog Computing as a sub-layer between cloud and devices leads to the reduction of load on the core network and cloud through the efficient resources management. 3 Uses the concept Fog Computing to present a resource management framework for resource management, estimation, and reservation. The implementation was done by Java and evaluated using CloudSim toolkit. Another role of Fog is dealing with mobile nodes with fluctuating connectivity behavior that causes unpredictable relinquish probability. M. Azam et al 4 takes into accounts this factor and design a resource management system based on fluctuating relinquish probability of customer and service type and service price. 5 Discuss the highly distributed servers are known as Nano Datacenters (nDC). It proposes flow-based and time-based energy consumption model. Regarding system design factors such as the type of access, applications (number of downloads, update, and pre-load) and the ratio of active time to idle time of Nano Datacenters can lead to energy saving.
The internet of things is composed of thousands of heterogeneous devices come in with different protocols, Platforms and data formats. Fog computing as sub-layer can provide services and ease interoperability among them. Several solutions have proposed for interoperability through virtual service delivery. 6 Introduce the paradigm of Fog of Things (FoT) and developed a self-organizing platform called SOFT-IoT; Self Organized Fog of Things. SOFT-IoT enables semantic interoperability and discovery of data as two major challenges. Semantic interoperability enables semantic annotation, identifying, recording and discovery of data. 7 Discuss IoT healthcare system for remote monitoring of patients and the role of fog layer in delivering services. The system includes sensor nodes, smart gateways with fog, cloud, and client back-end parts. For evaluation of interoperability of gateways several types of sensor nodes such as Bluetooth, Wi-Fi and 6LoWPAN were used. A. Rahmani et al. 8 9 enhance a healthcare monitoring system by using an interoperable smart gateway as a Fog computing. The gateway architecture is designed to support different versions of operating systems (different versions of Linux) and various sensor nodes producer (Texas Instrument, Zigduino Arago, and Zolertia) which operating under standard communication protocols such as Wi-Fi, 6LoWPAN, and Bluetooth. The smartness of gateways comes in the form of heterogeneous network technologies, standards and protocols to exchange data and work seamlessly. The interoperability comes in three levels of technical (different vendor with specific interfaces and standards), syntactic (format of exchanging messages) and semantic interoperability. In 10 a novel Fog node called IoT Hub was designed and implemented which was located at the edge of several physical networks in order to provide a management for heterogeneous smart objects. This IoT Hub operates link and application layer of the protocol stack (in particular HTTP and CoAP): at the link layer, it merges different physical networks into a single IP network and at the application layer enables resource discovery and interoperability among applications.