7DS: Exploring Multimodal Networking Henning Schulzrinne Dept. of Computer Science Columbia University NSF I/UCRC Planning Meeting, September 18, 2003

September 18, 2003WICAT NSF-I/UCRC Planning Meeting2 Wireless Network: filling the infrastructure-ad hoc gap Wireless networks: –Ubiquitous, fast, cheap: pick any two… Currently, varies from 0.1c to $4/MB Research has primarily explored: –one-hop infrastructure extension (2G, 3G, ) –multi-hop connected ad-hoc networks But: –2G/3G bandwidth will remain low and precious –hot spots not ubiquitous –ad hoc networks don’t scale – brittle if spanning large areas Our proposal: use mobile nodes to carry data

September 18, 2003WICAT NSF-I/UCRC Planning Meeting3 Applications Tourism: –get information about sights, travel, public transport schedules,.. –upload picture postcards and video recordings Transportation: –users in buses and trains leverage data capability Emergencies: –propagate “I’m alive” and rescue information Mobile sensors: –sensors spread too far to communicate directly with each other

September 18, 2003WICAT NSF-I/UCRC Planning Meeting4 7DS – a framework for intermittently connected networks Two directions for data: –Internet  mobile nodes –mobile nodes  Internet Each in multiple hops highlow high7DS hotspots lowsatellite SMS? voice (2G, 2.5G) bandwidth (peak) delay

September 18, 2003WICAT NSF-I/UCRC Planning Meeting5 Realization

September 18, 2003WICAT NSF-I/UCRC Planning Meeting6 Current status: prototype Initial Java implementation –search not just by URL, but by content –  greater likelihood of finding appropriate material (“news”) Working on PDA implementations Also, considering Linux embedded systems –low-power, self-contained

September 18, 2003WICAT NSF-I/UCRC Planning Meeting7 Combining cellular and 7DS networks Proposed research Cellular reselling –pay once for bandwidth, use many times Inverse multiplexing –for high-priority content Content location –find nearest hotspot Cache cleaning –indicate popular content for proactive querying –remove stale content in m  I

September 18, 2003WICAT NSF-I/UCRC Planning Meeting8 Expected Results & Impact Leverages low-cost mobile devices New services that otherwise are not cost-effective Low initial capital expenditure –re-use of infrastructure

September 18, 2003WICAT NSF-I/UCRC Planning Meeting9 Resource Requirements & Cost Three components: –theoretical investigation –prototype software –hardware modules Applying for NSF special-projects grant