# Priority-Based Content Delivery in the Internet of Vehicles through Named Data Networking +
Footnote †: This paper is an extended version of our paper published in: [PERSON]; [PERSON]; [PERSON] Named Data Networking for Priority-based Content Dissemination in VANETs. Workshop on Vehicular Networking and Intelligent Transportation systems (VENITS'16), co-located with PIMRC, 2016. The main concerns come from the fact that ideally, according to the IoV vision, a car should be able to utilize any and all of the available communication interfaces, such as 3G/Long Term Evolution (LTE), Wi-Fi and 802.11 Outside the Context of a Basic Service Set (OCB) to interact with either remote/edge servers or other vehicles, as needed by the wide range of supported applications, while meeting their heterogeneous delivery demands (e.g., in terms of reliability, timeliness), under poor connectivity due to mobility and harsh propagation conditions. In particular, OCB is the operational mode of IEEE 802.11, specifically conceived for vehicular communications, that allows nodes that are not members of a Basic Service Set (BSS) to transmit data without preliminary authentication and association [3]. It clearly emerges that networking plays a crucial role to fulfil such huge expectations. Today, there is a large consensus on developing \"information-centric\" approaches for vehicular environments [4] to satisfy the unmet challenges of current IP-dependent host-centric networking solutions. Information Centric Networking (ICN) and, in particular, its prominent example, Named Data Networking (NDN) [5], have attracted a significant interest in the research community as a promising solution for content search and delivery in the future Internet [6]. NDN shifts from the IP's communication model, focused on \"where\" the content is stored, to a content dissemination model caring about \"what\" content to retrieve. To this aim, in NDN, application-level content names are directly used for content retrieval, hence permitting a node to communicate without any need of name-to-IP address resolution. Names are hierarchically structured (possibly user-friendly) and consist of a variable number of components, similarly to Uniform Resource Locators (URLs), that can define the scope of the data. Nodes send Interest packets to ask for named Data packets, replied by any node owning or caching the requested content. The mentioned features make NDN particularly suitable for content retrieval in IoV, where: (i) vehicles are interested in retrieving content regardless of the identity of the node producing it (e.g., road congestion information, weather conditions, electric vehicle charging fees); and (ii) most of the content has a spatial and/or temporal scope. Caching, transparently performed at every NDN node, is particularly beneficial under the intermittent vehicular connectivity and can facilitate data retrieval by replicating contents in several nodes. Moreover, it can be applied at no additional cost thanks to the virtually unlimited storage capabilities of vehicular devices. A fundamental component of the NDN architecture is the \"strategy layer\", which is in charge of deciding where and when to forward incoming Interest packets, i.e., over which interface(s) and after  
Figure 1: The Internet of Vehicles scenario. which delay. Therefore, the definition of the NDN forwarding techniques to retrieve content [7; 8; 9; 10; 11; 12], by overhauling the functionalities of the strategy layer, is among the crucial design choices to tackle in vehicular NDN. To benefit from in-network caching and maximize the probability of content sharing, NDN typically assumes that packets are transmitted in broadcast over the wireless medium (usually the 802.11 OCB access technology is considered). Existing literature works mainly focused on the definition of solutions aimed to counteract broadcast storm effects and limit useless transmissions while speeding up data delivery [8; 9; 10; 11]. Overhearing is used to limit packet collisions and suppress redundancy.