1. Delay and Disruption Tolerant Networks Mostafa Ammar College of Computing Georgia Institute of Technology Atlanta, GA In Collaboration: Ellen Zegura (GT), Brian Levine and Mark Corner (UMass) Funding: NSF, DARPA, Cisco

2. The “Traditional” Ad-Hoc Wireless Paradigm  The Network is “Connected”  There exists a (possibly multi-hop) path from any source to any destination  The path exists for a long-enough period of time to allow meaningful communication  If the path is disrupted it can be repaired in short order  “Looks like the Internet” above the network layer

3. The Rise of Sparse Disconnected Networks

4. Sparse Wireless Networks  Disconnected  By Necessity  By Design (e.g. for power considerations)  Disruption-Tolerant Networks (DTNs)  Mobile  With enough mobility to allow for some connectivity over time  Data paths may not exist at any one point in time but do exist over time

5. New Communication Paradigms  Mobility used for connectivity  New Forwarding Paradigm Store Carry for a while forward  Special nodes: Transport entities that are not sources or destinations

6. Data Applications  Nicely suitable for Delay tolerant applications  Our work also considers the feasibility of flow-based applications

7. Delay and Disruption Tolerant Networks  A large burst of recent activities  Some commonality but also lots of different approaches  A coherent picture is beginning to emerge

8. Epidemic Routing

11. message is delivered…

12. SWIM* (*Shared Wireless Infostation Model)

13. Vehicle-to-Vehicle Networks Source Destination

14. Vehicle-to-Vehicle Networks Source Destination

15. Vehicle-to-Vehicle Networks Source Destination

16. DakNet

17. Our Work  The Message Ferrying Paradigm  Throwboxes to enhance capacity  Power Management in DTNs  Vehicle-to-Vehicle Networks  Prototyping and Testbed Efforts

18. Message Ferrying (MF)  Exploit non-randomness in device movement to deliver data  A set of nodes called ferries responsible for carrying data for all nodes in the network  Store-carry-forward paradigm to accommodate disconnections  Ferries act as a moving communication infrastructure for the network

19. Message Ferrying s

20. s

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22. MF Variations  Ferry mobility  Task-oriented, e.g., bus movement  Messaging-oriented, e.g., robot movement  Regular node mobility  Stationary  Mobile: task-oriented or messaging-oriented  Number of ferries and level of coordination  Level of regular node coordination  Ferry designation  Switching roles as ferry or regular node

23. Questions Our Research Answers  How to route the ferry  How to manage multiple ferries  How to insure fault tolerance

24. Throwboxes  Basic idea: add new devices to enhance data transfer capacity between nodes  Deploy throwboxes to relay data between mobile nodes  Throwboxes are:  small, inexpensive, possibly dispensable, battery-powered wireless devices  Some processing and storage capability  Easy to deploy and replenish

25. Example: DTN w/out Throwboxes

26. Example: DTN w/ Throwboxes

27. Our Work Considers  Placement of Throwboxes  Throwbox prototypes (UMass)

28. Throwboxes ProcessorIntel PXA255 400MHz Memory64MB SDRAM 32MB Flash Power consumption < 500mA Size3.5’’ x 2.5’’ Weight47g

29. V2V Networks  Vehicle Relaying  V3: Vehicle-to-Vehicle Video Streaming

30. A sample scenario Deadline

32. Prototyping Efforts  DTNrg Spec-Compliant implementation  Cisco Mobile Routers  DieselNet (UMass)

33. Concluding Remarks  Mobility-Assisted Data Delivery  FINALLY! A realistic mobile wireless network paradigm  Everything looks familiar but this is a truly different environment  Techniques developed have wide applicability  Fertile Ground for both networking problems and novel application paradigms

34. Concluding Remarks  Mobility-Assisted Data Delivery  FINALLY! A realistic mobile wireless network paradigm  Everything looks familiar but this is a truly different environment  Techniques developed have wide applicability  Fertile Ground for both networking problems and novel application paradigms