# Context-Aware Gossip-Based Protocol for Internet of Things Applications
## 2 Related Work  
Various characteristics of gossiping protocols have been investigated, including their handling of bounded and small-sized messages, low-frequency interactions between nodes, random peer selection, and the unreliable interaction assumption [20]. The power of a gossiping protocol lies in its symmetric simplicity, meaning that each node runs identical algorithms. A gossiping protocol will also operate correctly and adequately on a variety of topologies; thus, such protocols can arguably be considered topologically independent. Well-designed gossiping protocols can also eliminate the risk of disruptive load surges due to their production of bounded, almost negligible, loads. Despite these advantages, gossiping protocols also suffer from several limitations due to their bounded message sizes and low periodic message exchange rates. These limitations result in a distributed system with a severely limited information carrying capacity. The rest of this section reviews several research efforts that have focused on proposing modifications to the original gossiping protocol to address its limitations. The Location-based Gossiping (LGossiping) protocol was developed as an improved gossiping-based method of message distribution that is based on the locations of all nodes in the network [21]. This means that nodes reliably forward messages to known neighbours using the Global Positioning System (GPS). According to a comparative performance analysis with the original gossiping protocol as the benchmark, LGossiping, to some extent, solves the delay problem of the original protocol. Nevertheless, there are many instances in which the data fail to reach the sink. In addition, the network size was fixed to 100 nodes throughout the experiments. An improved version of the LGossiping protocol, Energy Location-based Gossiping (ELGossiping), bases its selection of the next node on its distance to the sink [22]. Therefore, when an event is detected by a node, the next hop is determined by selecting the neighbouring node with the maximum energy and the minimum distance to the sink. The performance of ELGossiping in terms of the number of live nodes, the energy consumption, and the packet loss was comparatively assessed against the performances of Gossiping and LGossiping. The findings showed that ELGossiping outperforms the other two protocols, with an increased network lifetime, a reduced number of hops and lower energy consumption. However, the authors did not mention how the distance to the main station is measured or determined. A chance-based gossiping protocol, CHGossiping, was proposed to overcome the delay problems of the LGossiping algorithm and to reduce the number of non-input events at the sink [23]. Similar to ELGossiping [22], this routing algorithm considers both a node's energy and its distance to the sink. In CHGossiping, the next-hop node is randomly selected with a probability based on the remaining energy of a node and its distance to the sink. A node's chance for selection is increased when it is closer to the sink and contains more residual energy. This approach decreases the delay and consumes energy more efficiently. The performance of CHGossiping was comparatively assessed against the performances of the original gossiping protocol and LGossiping [21] with regard to the network lifetime, energy consumption, and packet loss. The findings showed that CHGossiping performs better than the other two routing protocols; it proved to be more reliable and energy efficient, with an increased network lifetime. Although the chance parameter is calculated using both the node's energy and distance to sink, it is still sent in the node greeting packet along with the other parameters. This would cause some network overhead which was not considered in the design of the CHGossiping protocol. The Fair Efficient Location-based Gossiping (FELGossiping) protocol was later proposed to control the energy consumption of the nodes in a WSN during communication and thus to increase the network's lifetime [19].