Opportunistic email distribution and access in challenged heterogeneous environments.

The communication paradigms for delay-tolerant networking have been modeled after email. Supporting email over DTNs in a backwards compatible manner in a heterogeneous environment has yet to be fully defined. In this paper, we present a set of conventions for and extensions to the DTNRG architecture. We have implemented a system that is able to deliver emails within a DTN network, from a DTN network to the Internet, and from the Internet to the DTN network. Our system architecture includes multiple solutions for integrating traditional and DTN-based mail delivery: DTN-based messaging clients for mobile phones and PDAs, a dedicated, stand-alone DTN gateway between the Internet and the DTN network, and a personal DTN mail application proxy. The latter bridges to unmodified mail user agents running on a laptop.