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Challenged Networking

Challenged Networking. An Experimental Study of New Protocols and Architectures. Erik Nordström. Unchallenged Networking. Wired Stationary Conversational Structured End-to-end. The Challenges. Mobile computers No structures Intermittent connectivity No end-to-end paths

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Challenged Networking

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  1. Challenged Networking An Experimental Study of New Protocols and Architectures Erik Nordström

  2. Unchallenged Networking • Wired • Stationary • Conversational • Structured • End-to-end

  3. The Challenges • Mobile computers • No structures • Intermittent connectivity • No end-to-end paths • No pre-established names and addresses How to enable communication when requirements and assumptions change?

  4. The Solutions • Make existing protocols work better • Develop new protocols • Make existing and new protocols interoperable • Develop evaluation methodologies and testbeds

  5. Main Contributions • Experimental testbeds and methodologies • Ad hoc Protocol Evaluation (APE) • Protocol implementation and evaluation • AODV-UU, DSR-UU routing protocols • New communication paradigms • Interest-based dissemination • New network architectures • Haggle

  6. Challenges of Experimental Evaluation • Repeatability • Mobility • Radio • Management • Scaling • Configuration • Cross-environment • Simulation, emulation, real-world

  7. Related Work in Testbeds Orbit [Raychaudhuri et. al 2005] • Netbed/Emulab [White et. al 2002] • Whynet [Zhou et. al 2005] • Etc. DieselNet [Burgess et. al 2006] Roofnet [Aguayo, et. al 2003] [Above photo (c) 2006 Daily Hampshire Gazette]

  8. Experiment Choreography Go to position B in the middle of the corridor (5 secs) 2. Continue to position C at the end of the corridor (5 secs) Log SNR 3. Go back to starting point (10 secs) Log traffic Log parameters

  9. Experimental Setup Relay node swap Ping! 3 0 2 1 • Routing protocol implementations: • AODV-UU • DSR-UU • OOLSR

  10. Thesis page 204 Link cache poisoning Mean over 10 experiments

  11. DSR-UU Source route at sender Source routes Simulation Source route at receiver DSR-UU 3 3 0 0 Flip-flop routing Real world

  12. Haggle – An Architecture for Challenged Networking • Scenario: • People carry information • Ad hoc/opportunistic interactions • Heterogeneous connectivity • Problems: • How to agree on names and addresses? • How to exchange information? • How to agree on which information to exchange?

  13. The Haggle Approach: Searching Search for matching content Search for matching content 1 Interests 2 3 4 Interests 4 3 2 1

  14. Interest-based Dissemination interest message Match at least two interests!

  15. Three Interest-based Dissemination Strategies Wait – only disseminate from source Flood – any node may re-disseminate Content – intermediate nodes may re-disseminate (forward)

  16. What is the Correlation between Contacts and Interests? List of interests Affiliation Nationality Technical interests … 3 cm

  17. Trace-based Simulation 1000 messages uniformly spread over the trace. Match affiliation or nationality.

  18. Conclusions • Protocols and architectures for challenged networks cannot be designed solely based on simulations and emulations • Protocols need to be designed for intermittent connectivity, but they should also exploit full connectivity • Protocols need to rely more on decision making based on (long term) measurements of the environment, or on a-priori knowledge rather than lookup services • New naming and addressing schemes required. Schemes that support searching can be attractive for flexible content exchanges

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