Many emerging scientific and industrial applications require the capability to transfer large quantities of data, ranging from tens of terabytes to petabytes. Examples include the transport of high definition movies between studios and theaters, and the transport of large quantities of data from telescopes and particle accelerators/colliders to laboratories all around the world. A convenient property of many of these applications is their ability to tolerate delivery delays from a few hours to a few days. Such Delay-Tolerant Bulk (DTB) transfers are currently being serviced through the use of the postal system to transport hard drives and DVDs, or though the use of expensive dedicated networks.

In this work we have used traffic data from 200+ links of a large transit ISP to show that the naive approach of using end-to-end (E2E) connection oriented transfers can be prohibitively expensive under widely used 95-percentile charging schemes. We have also conducted extensive live measurements across multiple ISPs to show that the available bandwidth of E2E connections is subject to time-of-day effects.

Based on these observations, we proceed to design a system for performing Store-and-Forward transfer of DTB data. We evaluate the performance of our system under two scenarios: (1) 95-percentile charging, (2) flat-rate charging under time-of-day capacity constraints.