Spatial and temporal locality of content in BitTorrent: A measurement study

We conduct comprehensive measurements on content locality in one of the largest BitTorrent portals: The Pirate Bay. We investigate locality phenomena from a content perspective, considering the content category, publisher, and popularity of content. In particular, we focus on (i) how content is consumed from spatial and temporal perspectives, (ii) what makes content be consumed with disparity in spatial and temporal domains, and (iii) how we can exploit the content locality. We find that content consumption in real swarms is 4.56 times and 1.46 times skewed in spatial (country) and temporal (time) domains, respectively. We observe that a cultural factor (e.g., language) mainly affects spatial locality of content. Not only the time-sensitivity of content but also the publishing purpose affects temporal locality of content. We further reveal that spatial locality of content rarely changes on a daily basis (microscopic level), but there is notably spatial spread of content consumption over the years (macroscopic level). Based on the observation, we conduct simulations to demonstrate that bundling and caching can exploit the content locality.