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 No pre-established names and addresses How to enable communication when requirements and assumptions change?

Developments Mobile IP [Ioannidis:1991, Johnson:1993] Mobile Ad hoc Networks (MANETs) [Perkins:1994] Interplanetary Internet [Cerf:2001] Delay Tolerant Networks (DTNs) [Fall:2003] Sensor Networks, Opportunistic networks, Pocket Switched Networks (PSNs), etc. Mobility Wireless Constrained computation and energy Constrained computation and energy Delays Disruptions and disconnections Store-carry-forward

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

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

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

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

Experiment Choreography 1.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) 3. Go back to starting point (10 secs) Log SNR Log traffic Log parameters

Experimental Setup Relay node swap Ping! Routing protocol implementations: AODV-UU DSR-UU OOLSR Routing protocol implementations: AODV-UU DSR-UU OOLSR

Thesis page 204 Link cache poisoning Mean over 10 experiments

Simulation Real world Source route at receiver Source route at sender Flip-flop routing DSR-UU Source routes

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?

The Haggle Approach: Searching Interests Search for matching content

Haggle Demo Flower ? Flower

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

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

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

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

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