Trends and Challenges in Delay Tolerant Network (DTN) or Mobile Opportunistic Network (OppNet)

1.   Trends  and  Challenges  in  Delay  Tolerant  Network   (DTN)  or  Mobile  Opportunis<c  Network  (OppNet)     Special  Talk  on:  Dr.  Mazlan  Abbas,  UTHM   2  April  2014  

2. A little bit about the Speaker

3. Outline •  Motivation •  History of DTN •  Trends and Challenges in DTN •  Routing in DTN •  Performance of DTN in Emergency Scenario •  DTN Applications •  Future Work

4. Issues of Communications During Disasters and Emergency Lack of adequate communi cations Terrorist Attack Hurricane Tsunami Earthquake

5. Opportunistic Networks (OppNets) To enable communication between source and destination without the support of a fixed network infrastructure

6. Normal 3G 3G 3G 3G Base station 6

7. During Disaster X X 3G 3G X 3G X 3G Base station 7

8. History of the DTN Motivation

9. Imagine This… If I say a “Hello” to you and you hear it after … 9 hours!!!

10. Some Fast facts Time  taken  by  light     –    Earth  –  Jupiter          :  32.7  min     –    Earth  –  Saturn          :  76.7  min   –    Earth  –  Pluto              :  5.5  hours   –    Earth  –  Voyager1  :  13  hours   –    Earth  –  Voyager2  :  10.4  hours.    

11. [Source: TERENA Networking Conference 2000, 24 May 2000, Scott Burleigh, Vint Cerf, Bob Durst, Adrian Hooke, Keith Scott, Eric Travis, Howard Weiss

12. History of Delay Tolerant Network •  Interplanetary Internet (IPN) is a NASA research project led by Vint Cerf in 1998. •  The basic idea is to try to make data communications in space/ between planets. •  IPN became the most fundamental basis for DTN architecture and protocol suite. •  The Interplanetary Internet is a disconnected, store-and forward ‘network of Internets’ based on a wireless backbone with huge delays (The delay in sending or receiving data from Mars takes between 3.5 to 20 minutes at the speed of light) and error prone links •  Failing of IP/TCP in space missions –  End-to-end path exist –  Small delays

13. Delay Tolerant Networking (DTN) Source A •  DTN is a set of protocols that act together to enable a standardized method of performing store-carry-and- forward communications. B Store Carry •  Characteristics of DTN: i.  Intermittent connectivity –  No end-to-end path between source and destination ii. Long variable delay –  Long propagation delays between nodes B Forward C Store Carry C Forward D Delay Tolerant Network (DTN) = Mobile Opportunistic Network (OppNet)

14. Opportunistic Mobile Networks (DTN) Store-Carry-Forward •  Opportunistic networks typically wireless •  Nodes are typically handheld devices carried by people •  No infrastructure required •  Nodes communicate directly with each other

15. Why Ad Hoc Networks ? •  Setting up of fixed access points and backbone infrastructure is not always viable –  Infrastructure may not be present in a disaster area or war zone –  Infrastructure may not be practical for short-range radios; Bluetooth (range ~ 10m) •  Ad hoc networks: –  Do not need backbone infrastructure support –  Are easy to deploy –  Useful when infrastructure is absent, destroyed or impractical

16. Many Applications •  Personal area networking –  cell phone, laptop, ear phone, wrist watch •  Military environments –  soldiers, tanks, planes •  Civilian environments –  taxi cab network –  meeting rooms –  sports stadiums –  boats, small aircraft •  Emergency operations –  search-and-rescue –  policing and fire fighting

17. Leveraging The Power of Mobile Phones •  3.3 billion people worldwide use cell phones •  Mobile phones are integrated with Wi-Fi, cameras, Bluetooth, and others. – creates a huge number of contact opportunities

18. Smartphones – The Enabler GPS Camera Big Storage CPU Power WiFi

19. Public Safety 3G WiFi 3G 3G 3G Base station WiFi WiFi 19 OppNet in Emergency Response Scenario

20. Public Safety Smartphones (Nodes) can be carried by “Pedestrians” or “Vehicles” X X 3G WiFi 3G X 3G X Base Station down WiFi WiFi WiFi WiFi Send “SOS” messages Send photos of victims or self Can we send videos? What kind of file size? 20 OppNet in Emergency Response Scenario

21. Public Safety Internet X X 3G WiFi 3G X 3G X Base Station down WiFi WiFi WiFi WiFi Ability to Connect to Internet at Remote Ends Question: Can smartphones help us during Emergency Situation? Internet 21

22. Internet X X 3G DTN Gateway WiFi 3G X 3G X Base Station down WiFi WiFi WiFi WiFi DTN Gateway Internet 22

23. Challenges in Mobile Environments ·  Limitations of the Wireless Network ·  packet loss due to transmission errors ·  variable capacity links ·  frequent disconnections/partitions ·  limited communication bandwidth ·  Broadcast nature of the communications ·  Limitations Imposed by Mobility ·  dynamically changing topologies/routes ·  lack of mobility awareness by system/applications ·  Limitations of the Mobile Computer ·  short battery lifetime ·  limited capacities

24. Other Applications of DTNs Wildlife monitoring 1 Communication in rural villages 2 3 Emergency/military

25. Application Scenario – Wildlife Monitoring Do zebras in the African bush have a pattern of migration or do they just move around in a random fashion across the year? •  ZebraNet •  A Princeton University project •  Custom tracking collar with GPS (node) is put on the neck of the zebra. •  Nodes record zebra’s location and stores in memory. •  Nodes carry the data until meet another node. •  Exchanges data with another zebra when in communication range. •  Mobile base station (MBS) collects data from collars when researchers are in the field. •  MBS is not fixed, rather it moves and is only intermittently available •  Physical presence of the researchers is no longer required at the deployment site in order to collect and publish zebra mobility pattern data. •  Network connectivity is intermittent and opportunistic

26. Application Scenario – Communication in Rural Villages •  DakNet Goal: Bring Internet connectivity to rural areas It is aimed at providing cost-effective connectivity to rural villages in India, where deploying a standard Internet access is not cheap. Kiosks are built up in villages and are equipped with digital storage and short-range wireless communications. Mobile Access Points (MAPs) mounted on buses, motorcycles, etc., exchange data with the kiosks wirelessly. MAPs may also download requested info (news, music, etc.) and bring it to villages. Kiosks connectivity •  Dial-up - slow (28 kbps) •  Short range communication •  •  •  •  • 

27. Application Scenario – Military Soldiers need to be able to communicate with each other in the battlefield When M1 and M2 are both connected, data is transferred directly. When the link between M2 and satellite is disconnected, data is transferred to HQ for storage and later delivery to M2. When M2 is reconnected, data stored at HQ is delivered, even if M1 is disconnected. DTN technology can be used to achieve the communication even though the end-to-end connection does not exist. Ziyi Lu and Jianhua Fan. Delay/Disruption Tolerant Network and its Application in Military Communications, International Conference On Computer Design And Applications (ICCDA 2010), 2010.

28. Challenges Challenging Research in DTN/OppNet ROUTING TRUST

29. Routing Challenges C5 C3 Node Mobility C6 C3 C1 Destination C4 C2 Source Example: Disaster relief efforts, mining operations, health campaigns In emergency situations, entities with any sensing capabilities such as cellphones with GPS or desktops equipped with surveillance cameras, can be especially valuable for the OppNet.

30. Factors That Impact Performance Mobility Pattern Routing Mechanism Size of Area N1 Number of Nodes Node Speed N2 Type of Communication Transmission Range Buffer Size Message Size Time-to-Live Battery Life

31. Mobility Model

32. Mobility model Random Movement Random movement Map-constrained random movement Human behavior based movement Random Walk Random Waypoint Each mobile nodes starts at a random location and then move to a new location by randomly choosing a direction and speed. Each mobile nodes starts at a random location and staying there for a certain period of time (pause time) and at the end of the pause time, the nodes select a random destination and move to the selected destination at a random speed. •  • 

33. Mobility model Map-constrained random movement e.g. KLCC (A) to KL Pavilion (B) Random movement Map-constrained random movement Human behavior based movement Random Map-Based Movement Shortest Path Map-Based Movement Routed Map-Based Movement 1 2 move from stop to stop using shortest paths nodes follow certain route (e.g. bus) •  • 

34. Can we do better?

35. Closing the Gap + Opportunistic Networks Social Networks Close the gap between human and network behavior •  Opportunistically follow the way humans come into contact •  Exploit human relationships •  Built more efficient and trustworthy protocols • 

36. Human, electronic, and virtual social networks. Embedding the social relationships in the electronic world identifies at least two levels in an opportunistic environment: an electronic social network (where relationships depend on the physical properties) and a virtual social network that builds an overlay atop the electronic social network.

37. Social Network Routing A technique for determining the paths that data takes across networks based on social behavior patterns (social contact, interest, and relationships) The social importance of a user in facilitating the communication among other users Social Contact Users with common interest are usually friends and tend to contact each other more frequently Social Interest Users are formed into groups according to their social relationship Social Relation

38. Human Behavior Based Movement Mobility model Random movement Map-constrained random movement Working Day Movement Model (WDM) Human behavior based movement Bring more reality of human movement patterns during a working day It produces similar Inter-contact times and contact durations as real world traces All nodes move on a real world map There are three major activities: 1.  Staying at home – node wake up in the morning 2.  Working at the office - go to the office and works 8 hours 3.  Doing some activity with friends in the evening •  •  •  •  Use different transportation between activities (bus, car or walking) •  EKMAN, F., KER¨A NEN, A., KARVO, J., AND OTT, J. Working Day Movement Model. In Proc. 1st ACM/SIGMOBILE Workshop on Mobility Models for Networking Research (May 2008).

39. Routing

40. Routing When and where to forward data? Jack is at school School bus is just coming John have a message for Jack

41. Routing protocol Epidemic: Epidemic Routing for Partially Connected Ad Hoc Networks Epidemic Prophet Spray and Wait Spray and Focus Concept: Floods messages into the network Goal: Maximize message delivery rate Disadvantages: •  High resources usage (buffer) •  High overhead Mrs. Wilson This is for Mrs. Wilson I will give the copy to everyone I meet, and hopefully it will reach her [Ref: A. Vahdat and D. Becker. Epidemic Routing for Partially Connected Ad Hoc Networks. Technical Report CS-2000-06, CS. Dept. Duke Univ., 2000.]

42. Routing protocol Epidemic Prophet: Probabilistic Routing Protocol using History of Past Encounters and Transitivity Prophet Spray and Wait Spray and Focus Concept: Use past encounters to predict future best Goal: Improve the performance of Epidemic Disadvantage: No guarantee to meet a better node in a message life time Mrs. Wilson This is for Mrs. Wilson Let me do it. I will probability meet her as usual 1.0 A or B ? Decision based on delivery probability and transitivity (the probability for a node to encounter a destination) A 0.5 0.7 ? S D X B 0.5 0.3 [Ref: A. Lindgren, A. Doria, and O. Schelen. Probabilistic Routing in Intermittently Connected Networks. ACM Mobile Computing and Communications Review, 2003.]

43. Simulation parameters Simulation area: 1500 x 300 m Number of nodes: 50 Mobility model: Random Waypoint Epidemic Epidemic Prophet Prophet 100m 100m 50m 50m Prophet Epidemic Epidemic Prophet Received messages with different Queue size Number forwarded messages with different Queue size Prophet has lower overhead than Epidemic Prophet has higher received messages than Epidemic

44. Routing protocol Spray and Wait: Efficient Routing in Intermittently Connected Mobile Networks: The Multiple-copy Case Epidemic Prophet Spray and Wait Spray and Focus Mrs. Wilson Concept: Controlled flooding / Limit number of copies made Goal: to reduce the overhead of Epidemic Disadvantage: •  High delay •  Random Movement (If the nodes that receive a copy of the bundle never cross paths with the destination, the system fails completely) This is for Mrs. Wilson I will spread four copies to first four that I meet, and hopefully it will reach her Spray Phase Wait Phase Source will generate and distribute a small number of copies to only a few relay Each relay carries its copy until it meets the destination and delivers it directly to the destination (each relay will forward its copy only to the destination) [Ref: Spyropoulos, T., Psounis, K., and Raghavendra, C. S. Spray and Wait: An Efficient Routing Scheme for Intermittently Connected Mobile Networks. In Proc. of the ACM SIGCOMM Workshop on Delay-Tolerant Networking (WDTN) , 2005.]

45. Simulation parameters Simulation area: 200 x 200 m Number of nodes: 100, 200 Mobility model: Random Waypoint Epidemic Epidemic Spray & Wait Spray & Wait The number of transmissions for Spray and Wait are very less than Epidemic

46. Routing protocol Spray and Focus: Efficient Mobility-assisted Routing for Heterogeneous and Correlated Mobility Epidemic Prophet Spray and Wait Spray and Focus Concept: Limit number of copies made / controlled flooding Goal: To reduce the delay of Spray and Wait I will spread four copies to first four that I meet, and the four person will forward that copies to someone else closer to Mrs. Wilson, and hopefully it will reach her Mrs. Wilson This is for Mrs. Wilson Spray Phase Focus Phase Source will generate and distribute a small number of copies to only a few relay Each relay will forward its copy to another relay (the selection of relay is based on single- copy utility based scheme) [Ref: T. Spyropoulos ,and K. Psounis. Spray and Focus: Efficient Mobility-assisted Routing for Heterogeneous and Correlated Mobility. Proc. of IEEE Percom International Workshop on Intermittently Connected Mobile Ad Hoc Networks, March 2007.]

47. Simulation parameters Simulation area: 4500 x 3400 m Number of nodes: 300 Transmit range: 10 m Transmit speed: 250 Kbyte/s Mobility model: Map Route Movement Spray&Foc us Spray&Wai t Spray&Foc us Spray&Wai t When the value of TTL increases , the delivery ratio increase Spray and Focus seem to perform slightly better than Spray and Wait in term of delivery ratio When the value of TTL increases, the delivery latency decreases Spray and Focus has lower delivery latency than Spray and Wait [Ref: Jianwei Niu, Jinkai Guo, Qingsong Cai, Norman Sadeh, and Shaohui Guo. Predict and Spread: an Efficcient Routing Algorithm for Opportunistic Networking. Proc. of IEEE Wireless Communications and Networking Conference (WCNC), March 2011.]

48. Routing protocol MaxProp: Routing for Vehicle-Based Disruption-Tolerant Networks Epidemic Spray and Wait Spray and Focus Prophet My packets are full, and I had the message long enough, and I am sure someone else gave the message to her This is for Mrs. Wilson MaxProp Concept: Packet Dropping Policy (schedule packets transmission to its peers and determines which packets should be deleted when buffer space is almost full. Packets are schedule based on encounter history of nodes throughout the network) Goal: To increase the delivery rate and lower latency Disadvantage: High processing cost in large scale networks [Ref: J. Burgess, B. Gallagher, D. Jensen, and B. Levine. MaxProp: Routing for Vehicle-Based Disruption-Tolerant Networks. Proc. of the 25th INFOCOM, 2006.]

49. Can Opportunistic Network support Emergency Scenario? C3 C1 Node Mobility D C1 S Destination Example: Disaster relief efforts, mining operations, health campaigns C2 Source In emergency situations, entities with any sensing capabilities such as cellphones with GPS or desktops equipped with surveillance cameras, can be especially valuable for the OppNet.

50. Performance Evaluation of Binary Spray and Wait OppNet Protocol in the Context of Emergency Scenario Mazlan Abbas, Nur Husna and Norsheila Fisal PerNEM 2013 In Cooperation with the 3rd International Workshop on IEEE PerCom 2013 Pervasive Networks for Emergency Management March 22, 2013, San Diego, California, USA [Note: Check Results in Slideshare - http://www.slideshare.net/mazlan1/per-nem-2013-slideshare ]