Navigability in Social Networks of Objects: The Importance of Friendship Type and Nodes' Distance

Abstract

The Social Internet of Things (SIoT) is a novel communication paradigm according to which objects connected to the Internet create a dynamic social network that is mostly used to: route information and service requests, disseminate data, and evaluate the trust level of each member of the network. The performance of these processes is clearly dependent on the following SIoT aspects: i) the structure of the social network; ii) the types of service/information requests that will mostly characterize the interaction in the IoT/SIoT; iii) the rules used to navigate the social network. This paper aims at studying these aspects through simulations as follows. The importance of each type of social relationship with respect to the navigability is observed in terms of key parameters, such as the average path length, the network diameter and size of the giant component. The concepts of nodes' geographical and similarity distances are introduced to analyse the navigability; these are then used to evaluate the performance when the communications involve objects at increasing distance. Results confirm that some types of social relationships do not appear to be useful and that the introduction of the node average distance significantly changes the resulting SIoT performance.