**8. Decentralized monetization architecture**

The decentralized monetization architecture shown in **Figure 3** consists of cloud servers, public fog nodes, edge devices, and a smart contract whose major function is ensuring monetization and a structured, logical revenue exchange between fog nodes and edge devices. In this kind of monetization architecture, the cloud or fog provider has no control or authority over the monetization and pricing model of services rendered by the fog nodes. The monetization strategy is shared between the fog service provider and the end user through a smart network, for example, blockchain. The blockchain network accesses the quality of service the fog devices provide and determines the pricing model to employ between the end user and the fog service provider.

The Ethereum smart contract was the monetization smart contract [35]. The smart contract was divided into fog node provider only, device only, and fog only as the layers of authorization provided in the Ethereum smart contract, and each entity, as the name of the layer suggests, can only access layers present to it. The edge devices

**Figure 3.** *Decentralized monetization architecture of fog node.*

#### *A Survey on IoT Fog Resource Monetization and Deployment Models DOI: http://dx.doi.org/10.5772/intechopen.113174*

are registered in the smart contract, and the device deposits an initial amount. The interaction between the fog node, Ethereum smart contract, and edge devices enables money to be paid to the fog node for services rendered or money refunded by the fog node if there is a breach in trust between the fog nodes and the device. Also, an individual or a particular organization may own a set of fog nodes. These fog nodes generate, curate, and process raw data in a specific geographical area. These processed data may not all be needed by the organization. Lizcano [43] presents a way of monetizing these fog nodes with other fog nodes owned by an individual or organization needing those processed data. Guevara et al. [24] propose a digital marketplace where fog nodes requiring a specific data set can connect with others to get the required data using blockchain and FIWARE technology. The blockchain ensures trust between fog nodes during data exchange and implements the pricing model configured in the smart network while data is being exchanged. FIWARE technologies ensure the interoperability of data between the fog nodes. The blockchain ensures trust and nonrepudiation between the devices, while the FIWARE technologies ensure interoperability between the connected fog nodes. Furthermore, fog computing depends on joint action between several infrastructure operators and service providers who manages and operates this infrastructure pose a major challenge. Also, resource allocation is still a major problem for fog computing instances. A user-participatory fog computing architecture was proposed in [25]. This fog architecture is similar to a WIFI architecture where users connect to the WIFI with their devices. Likewise, in the model, services provided by fog benefit the users when they install fog devices to the network. In contrast, the fog container placement is controlled by fog managers to make it feasible. After successfully connecting to the network, the user registers fog devices in the fog portal. The fog portal between the corresponding resources plays an intermediary role.

The decentralized fog monetization architecture obliterates the issues of QoS and third-party fees faced by centralized architecture. The decentralized architecture employs smart contract technology with algorithms written for the monetization and pricing model. The interaction between the public fog nodes and the edge devices is made public to all network members through a public ledger. The trust between the customer and fog node providers is restored, and the quality of service is tracked at each stage. Once it drops below a certain standard, there is a breach of trust between the fog node and the edge device, and a refund of revenue is demanded [23]. Fog nodes with more trust issues are flagged by the blockchain network and avoided by other fog devices. Their system reputation is monitored, which keeps the fog providers in check.
