DTN meets smartphones: future prospects and tests

Although first conceived for the Interplanetary Internet, DTN (Delay-/Disruption-Tolerant Networking) architecture has successively enlarged its application scope to embrace all “challenged networks”, i.e. networks where the TCP design key assumptions of short RTT, no disruptions, and continuous end-to-end path availability are challenged. The distinctive features of DTN architecture seem ideal for the connectivity problems of modern smartphones. These are both PCs and cell phones and are characterized by a wide range of different communications technologies, including Bluetooth, WiFi, and advanced 3G radio interfaces, like UMTS HSPA (High-Speed Packet Access). The aim of this paper is to show that it is both feasible and useful to adopt DTN architecture on these advanced devices, in addition to the usual TCP/IP protocol stack. To this end, a series of tests is presented and discussed in the paper, considering various communication interfaces, 3G in particular. Tests were greatly facilitated by the introduction onto the market of some smartphones running Linux based operating systems, like Maemo, which allowed the authors the direct use of “official” DTN code (i.e. the DTN2 reference implementation and the DTNperf_2 evaluation tool).