# Smart Collaborative Caching for Information-Centric IoT in Fog Computing
## 1 Introduction  
The idea of the Internet of Things (IoT) has been acknowledged as a popular term for many years. Nowadays, it is attracting more attention from both industrial and academic communities than ever. Different from the Wireless Sensor Networks (WSN), IoT extends the scope of nodes and connectivities tremendously [1; 2]. A batch of schemes and protocols are proposed by many standardization organizations, such as IETF, ISO, IEC, ITU, IEEE, 3 GPP, GS1, to enhance the overall performance of IoT. For instance, there are several active working groups in IETF: 6 Lo, 6 tisch, ace, core, dentet, lwig, manet, roll and so on. This latest progress empowers IoT to be easily utilized in intelligent transportation systems [3; 4], e-health [5; 6], smart grid [7; 8], and other common scenarios [9; 10].  
Fog computing is a novel paradigm which leverages many useful features of IoT to aggregate many small nodes and achieve a significant capacity. It could be perceived as an intermediate stage between cloud computing and personal computing. New research directions, such as D2D, M2M, V2V,are providing a substantial basis for it. Many new promising applications, e.g., virtual reality and augmented reality, can profit from fog computing.  
However, the conjunction between IoT and fog computing is not smooth due to the drawbacks of the traditional network architecture. As a competitive clean-slate candidate, Information-Centric Networking (ICN) is engaged in modifying the original host-oriented pattern. By including more information-oriented characteristics into IoT, ICN may inspire more innovations in fog computing scenarios.  
This paper focuses on several tough issues: Firstly, the connections among multiple IoT nodes are usually unconsolidated. Guaranteeing the data distributions in such circumstance is hard. However, the cooperative processing needs a firm foundation. Secondly, due to the constrained resource of IoT nodes, the information storing needs to be explored. When the capacity is not sufficient, the node should find an approach to achieve caching ability which is the basis of ICN. Thirdly, the content can be uploaded based on the requirements if previous connecting and caching capability are ready. Quickly locating the most suitable node is significant not only for the users but also for the network.  
The main contributions of this work could be summarized in two aspects: (1) A new Smart Collaborative Caching (SCC) scheme is designed to enable information-centric ability in IoT, which is beneficial for better connecting the devices and providing cooperative caching in fog computing. (2) The validation results are illustrated based on analyzing the performance of common IP network, ICN flooding, ordinary SCC and enhanced SCC. The topology, scenarios, and experiments are also carefully detailed.  
The basic structure of this paper is as follows: In Section 2, the related work in combining IoT with ICN and fog computing are presented respectively. In Section 3, the details of SCC design are introduced. Three necessary parts, i.e., preliminary foundation, model establishment and primary operations are involved. In Section 4, the validations are given to explore the capacity of SCC. Two scenarios, two experiments, and four candidates are implemented and discussed. In Section 5, the paper is summarized and future works are presented.