Ubiquitous Interpersonal Communication over Ad-Hoc Networks and the Internet

Abstract

The hardware and low-level software in many mobile de- vices are capable of mobile-to-mobile communication, in- cluding ad-hoc mode for 802.11, Bluetooth, and cognitive radios. We have started to leverage this capability to provide in- terpersonal communication both over infrastructure networks (the Internet), and over ad-hoc and delay-tolerant networks composed of the mobile devices themselves. This network is fully decentralized so it can function with- out any infrastructure, but takes advantage of Internet con- nections when available. Devices may communicate when- ever they are able to exchange packets. All interpersonal communication is encrypted and authenticated so packets may be carried by devices belonging to untrusted others. One challenge in a fully decentralized network is rout- ing. Our design uses Rendezvous Points (RPs) and Dis- tributed Hash Tables (DHTs) for delivery over the Internet, and hop-limited broadcast and Delay Tolerant Networking (DTN) within the ad-hoc network. Each device has a policy that determines how many pack- ets may be forwarded, and a packet prioritization mecha- nism that favors packets likely to consume fewer network resources. A goal of this design and implementation is to provide useful interpersonal communications using at most 1% of any given resource on mobile devices.