From the Rocks of Mars to the Slums of Cambodia: The Unexpected Evolution of Research

Transcription

1 From the Rocks of Mars to the Slums of Cambodia: The Unexpected Evolution of Research Khaled A. Harras, Ph.D. Assistant Teaching Professor Founder and Director of the Networking Systems Lab (NSL) School of Computer Science Carnegie Mellon University

2 Outline Story 1: Evolution: From 4 nodes to 1.1Billion Story 2: Operation: How does all this roughly work? Story 3: Mobility: Common problems and solutions Story 4: DTNs: The unexpected evolution of research

3 The Internet in 1969 Source:

4 The Internet in 1971

5 The Internet in 1977

6 The Internet in 1999 Source:

7 The Internet: Some Stats

8 More Stats

9 More Stats Source:

10 Asia has started using the Internet!

11 Story Punch-line From To Research is the core for enabling this

12 Research Results

13 Outline Story 1: Evolution: From 4 nodes to 1.1Billion Story 2: Operation: How does all this roughly work? Story 3: Mobility: Common problem and solutions Story 4: DTNs: The unexpected evolution of research

14 Class Experiment Small game to send messages What are the problems we can have? OPEN DISCUSSION

15 Protocol Layers Source: and

16 Networking Problems What are the problems we can have? Connection establishment Reliability Flow control Error control Multiple applications Many protocols Routing Congestion Control.!

17 Example: Routing Build Routing Tables Lookup address Forward packets Source: and

18 Outline Story 1: Evolution: From 4 nodes to 1.1Billion Story 2: Operation: How does all this roughly work? Story 3: Mobility: Common problems and solutions Story 4: DTNs: The unexpected evolution of research

19 Today s Internet: Simple View

20 Can we handle mobility? Increased wireless network deployment, and available Mobile devices High mobility and user expectation: I must have network access NO MATTER WHAT..!!!

21 Mobility: Just the beginning Source: Chetan Sharma Consulting

22 Solutions: Single-hop wireless

23 Solutions: Ad hoc Networks

24 Solutions: Mesh Networks

25 So Can we handle Mobility..?

26 Outline Story 1: Evolution: From 4 nodes to 1.1Billion Story 2: Operation: How does all this roughly work? Story 3: Mobility: Common problems and solutions Story 4: DTNs: The unexpected evolution of research

27 Today s Internet: Unstated Assumptions A path exists between endpoints Routing protocols find the best path, or even a path Small end-to-end RTT Millisecond range End to end reliability works well Especially for low data loss rates Loss = Congestion Packet switching is the right abstraction IP does best effort delivery for each packet separately

28 The Rocks of Mars In 1998 the CCSDS (Consultative Committee for Space Data Systems) founders teamed with Vint Cerf to develop the IPNSIG formed in September Objective: Define the architecture and protocols for an InterPlanetary InterNet: IPN Vision: A network of Internets

29 Inter-Planetary Internet A 30 year vision

30 Fine, those guys are just crazy Why do we care..?

31 The Rise of New Applications

32 New Common Assumptions Very large delays RTT could range from milliseconds to days Ex: propagation between Earth and Mars Intermittent/disconnected links and paths End to end connectivity might never exist Routers may need significant persistent storage High link error rates RF interference, light or acoustic interference Loss is due to corruptions, not congestion Heterogeneous underlying networks and protocols Some specialized networks may not run IP, and run customized protocols that better suit them

33 IPN Upgraded to DTN Delay/Disruption Tolerant Networks DTNRG was formed in 2002 to generalize concepts introduced by the IPNRG Goal: achieve interoperability among heterogeneous networks in extreme environments Outcome: DTN Architecture and many protocols

34 How about other simpler applications? The Slums of Cambodia

35

36 Are you kidding..! Who will pay for this?

37 The Bottom of the Pyramid Annual Purchasing Power in $US > $20,000 Wealthy Nations adjacent Population In Millions Middle markets Class $2,000 $20,000 in developing 2,000 countries emerging mass markets < $2,000 4 Billion People 4,000 Earning less than $2,000/year 100 Source: Prahalad & Hammond, Harvard Business Review, Vol. 80, Issue 9 (Sep. 2002), pp48-58

38 The Bottom of the Pyramid 3-4 billion people with per-capita equivalent purchasing power less that US$2,000 per year Could grow to 6-8 billion over the next 25 years Most live in rural villages or urban slums and shanty towns Motivated towards urbanization and education Dharavi, one of the poorest villages in India: 85% have a TV, 50% have a pressure cooker, 21% have a telephone but can t afford a house! Even the poorest of the poor in Bangladesh: Devote 7 percent of income to communications services (GrameenPhone)

39 Mobile devices are starting to converge and have access to multiple networks Shouldn t we take advantage of these multiple networks? Specially in challenged environments? Numerous Problems... The future of DTNs

40 Outline Story 1: Evolution: From 4 nodes to 1.1Billion Story 2: Operation: How does all this roughly work? Story 3: Mobility: Common problem and solutions Story 4: DTNs: The unexpected evolution of research What to take from this talk?

41 Research is a MUST!

42 Thank You..! Questions?

43 Contribution I: Delay Tolerant Mobile Networks (DTMNs) MANETs rely on end-to-end routes S What do we do in sparse mobile networks? At that point in time: Flooding delivers too expensive Can we simply reduce the cost? DTMN Architecture Controlled flooding schemes Evaluation via simulation Summary and Conclusions We can significantly reduce the cost of flooding Few high-end nodes make a big difference The challenge is to tweak the knobs D

44 Contribution II: Clustered DTMNs and Messenger Scheduling S What happens if clusters are formed? Clustered DTMNs Use dedicated messengers between regions Point to point vs Path travel Messenger management: Ownership and Scheduling Algorithms Evaluation via analysis and simulation Summary and Conclusions No best scheme ; tradeoffs depend on the network/traffic patterns Picking the best scheme is a challenge and depends on which metric has more importance; we provide such knowledge Adaptive strategies are very useful in such scenarios D

45 Contribution IV: Intermittent Connectivity Shift focus to a single device experiencing Disruption rather than How Delay do we make use of available opportunistic connections? Intermittent Connectivity & DBS-IC View data while offline An SA bundles data, delivers to MA whenever possible Evaluation via implementation Summary and Conclusions Improvement due to bundling, single connections, and smaller RTT Mini-bundles is a major parameter Solution requires no network change for deployment AP S AP AP D

46 DBS-IC

47 ParaNets