# Semantic Distributed Data for Vehicular Networks Using the Inter-Planetary File System
## 8 Conclusions  
In this paper, we have proposed the creation of a P2P content-delivery network for vehicles and RSUs. The content of this network would be organized as semantic data, with all their associated advantages and benefits. In order to create this network, we have selected the open-source IPFS protocol. IPFS networks provide P2P search and data distribution over standard IP networks. However, the protocol has not been designed with vehicular networks in mind. The aim of this paper has been, hence, to study the possibility of using IPFS for the proposed vehicular network service. The current research and experimental results have shown that it is easy to use IPFS to create and validate a content-addressed network formed by up to 30 peers. It is also possible to test it against the public IPFS network, formed by thousands of peers. IPFS uses standard IP technology to provide content-based addressing in opposition to host-based solutions. This feature would allow vehicles, RSUs, and other IoT devices to directly share content with any other node, without needing to connect to any server, or know the IP addresses or domain names of their neighbors. This paper has also shown that the resultant P2P network offers most of the functionality advantages of the highly regarded information-centric networking technologies. Vehicles would be able to connect to the IPFS network through any RSU and easily fetch the semantic content shared by any node of the network. Three key and unique features make IPFS especially suitable for this application compared to other P2P solutions. First, its native and efficient support of semantic data using JSON. Second, the concept of IPNS address: every node has an exclusive address to publish secure and trusted content, reachable by anyone, without the need for centralized servers. Third, the recent addition of the QUIC protocol, more efficient and robust than the traditional use of TCP or UDP connections. The experimental results have been compared with recent simulations of both content-based and host-based algorithms. The analysis of the results has revealed that IPFS incurs a noticeable penalty during the initial connection, mostly due to the usage of TLS for authentication and encryption. These are two security features that were not included in the state-of-the-art simulations used for comparison. When IPFS is used to get multiple content requests, IPFS cost quickly decreases, reaching the excellent numbers estimated by the CDVC simulation. IPFS is inefficient when a vehicle needs to retrieve just one message with a few bytes of information, but highly cost-effective when the data required by the vehicle are fragmented in tenths of small JSON files. It is important to stress that those are exactly the kind of requests that a semantic agent running on the vehicle would do. In summary, it would be inefficient for vehicles to use IPFS to get a single content request, but that is going to be extremely rare in a semantic case. Semantic data are formed by tenths of interlinked entries. A vehicle requesting data would start doing a single request, process it, and immediately perform multiple requests to get all the related data, without disconnecting from the network. IPFS is perfectly suited for requests of this kind, as it provides immediate access to the requested data, and optimizes the network usage when multiple simultaneous requests are performed. The main conclusion of this paper is that IPFS is a very promising solution for exchanging semantic data in vehicular networks. The resultant P2P network offers a great balance between functionality, performance, and security. The results have been limited to a few specific situations in order to be able to compare them with state-of-the-art simulations. However, future lines of research