Leveraging MANET-Based Cooperative Cache Discovery Techniques in VANETs: A Survey and Analysis

Vehicular networking is an emerging technology that holds the great promise of supporting innovative safety and nonsafety applications. Vehicular ad hoc networks (VANETs) share many of the same challenges that are encountered within more general mobile ad hoc networks (MANETs). However, by the very nature of the vehicular environment, each of these challenges may be of greater or lesser significance. Communication channel loading and changing network topology tend to be of greater concern. Battery, computing, and memory resource utilization tend to be of lesser concern. Cooperative caching is an approach that has been used extensively within MANETs to address various performance and resource challenges. Applied properly, cooperative caching can significantly reduce overall bandwidth utilization. However, within the vehicular environment, care must be taken to not overly rely on topographical knowledge during cache discovery. In this paper, we develop a unique taxonomy for cache discovery, survey a representative set of MANET-based cooperative caching schemes, and classify the associated cache discovery techniques within the taxonomy. Using this classification, we then highlight the various cache discovery techniques that have been utilized, analyze their potential in addressing the specific challenges that occur when deploying non-safety applications within VANETs, and identify general pitfalls that should be avoided. Future research can utilize the results of this analysis to develop novel cooperative caching schemes that will offer better performance within VANETs when compared to existing MANET-based cooperative caching schemes.