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

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

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

  1. 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. 2. A little bit about the Speaker
  3. 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. 4. Issues of Communications During Disasters and Emergency Terrorist Attack Hurricane Tsunami Earthquake Lack of adequate communi cations
  5. 5. Opportunistic Networks (OppNets) To enable communication between source and destination without the support of a fixed network infrastructure
  6. 6. 6 3G 3G 3G 3G Base station Normal
  7. 7. 7 3G 3G 3G 3G Base station During Disaster X X XX
  8. 8. History of the DTN Motivation
  9. 9. Imagine This… If I say a “Hello” to you and you hear it after … 9 hours!!!
  10. 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. 11. [Source: TERENA Networking Conference 2000, 24 May 2000, Scott Burleigh, Vint Cerf, Bob Durst, Adrian Hooke, Keith Scott, Eric Travis, Howard Weiss
  12. 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. 13. Delay Tolerant Networking (DTN) •  DTN is a set of protocols that act together to enable a standardized method of performing store-carry-and- forward communications. •  Characteristics of DTN: i.  Intermittent connectivity –  No end-to-end path between source and destination ii. Long variable delay –  Long propagation delays between nodes A B B C C D Source Store Carry Forward Store Carry Forward Delay Tolerant Network (DTN) = Mobile Opportunistic Network (OppNet)
  14. 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. 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. 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. 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. 18. Smartphones – The Enabler CameraGPS WiFi Big Storage CPU Power
  19. 19. 19 3G WiFi WiFi WiFi 3G 3G 3G Base station OppNet in Emergency Response Scenario Public Safety
  20. 20. 20 3G WiFi WiFi WiFi 3G 3G Base Station down X X XXWiFi WiFi OppNet in Emergency Response Scenario Public Safety Smartphones (Nodes) can be carried by “Pedestrians” or “Vehicles” Send “SOS” messages Send photos of victims or self Can we send videos? What kind of file size?
  21. 21. 21 3G WiFi WiFi WiFi 3G 3G Base Station down X X XXWiFi WiFi Internet Internet Ability to Connect to Internet at Remote Ends Public Safety Question: Can smartphones help us during Emergency Situation?
  22. 22. 22 3G WiFi WiFi WiFi 3G 3G Base Station down X X XXWiFi WiFi Internet Internet DTN Gateway DTN Gateway
  23. 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. 24. Other Applications of DTNs Wildlife monitoring 1 3 2 Communication in rural villages Emergency/military
  25. 25. Application Scenario – Wildlife Monitoring •  ZebraNet Do zebras in the African bush have a pattern of migration or do they just move around in a random fashion across the year? •  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. 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. 27. Application Scenario – Military 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. 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. When M2 is reconnected, data stored at HQ is delivered, even if M1 is disconnected. Soldiers need to be able to communicate with each other in the battlefield DTN technology can be used to achieve the communication even though the end-to-end connection does not exist.
  28. 28. Challenges Challenging Research in DTN/OppNet ROUTING TRUST
  29. 29. C1 C6 C3 C2 C3 C5 Node Mobility Source Destination 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. C4 Routing Challenges
  30. 30. N1 N2 Mobility Pattern Node Speed Type of Communication Transmission Range Buffer Size Battery LifeTime-to-LiveMessage Size Routing Mechanism Number of Nodes Size of Area Factors That Impact Performance
  31. 31. Mobility Model
  32. 32. Random Movement Random Walk Random Waypoint Mobility model Random movement Human behavior based movement Map-constrained random movement •  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. •  Each mobile nodes starts at a random location and then move to a new location by randomly choosing a direction and speed.
  33. 33. Map-constrained random movement e.g. KLCC (A) to KL Pavilion (B) •  move from stop to stop using shortest paths •  nodes follow certain route (e.g. bus) Mobility model Random movement Human behavior based movement Map-constrained random movement Random Map-Based Movement Shortest Path Map-Based Movement Routed Map-Based Movement
  34. 34. Can we do better?
  35. 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. 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. 37. Social Network Routing Social Contact The social importance of a user in facilitating the communication among other users Social Interest Users with common interest are usually friends and tend to contact each other more frequently Social Relation Users are formed into groups according to their social relationship A technique for determining the paths that data takes across networks based on social behavior patterns (social contact, interest, and relationships)
  38. 38. Human Behavior Based Movement Mobility model Random movement Human behavior based movement Map-constrained random movement 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). •  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) Working Day Movement Model (WDM)
  39. 39. Routing
  40. 40. Routing When and where to forward data? School bus is just coming Jack is at school John have a message for Jack
  41. 41. This is for Mrs. Wilson I will give the copy to everyone I meet, and hopefully it will reach her Concept: Floods messages into the network Goal: Maximize message delivery rate Disadvantages: •  High resources usage (buffer) •  High overhead Epidemic: Epidemic Routing for Partially Connected Ad Hoc Networks [Ref: A. Vahdat and D. Becker. Epidemic Routing for Partially Connected Ad Hoc Networks. Technical Report CS-2000-06, CS. Dept. Duke Univ., 2000.] Epidemic Spray and Wait Routing protocol Spray and Focus Prophet Mrs. Wilson
  42. 42. 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 Prophet: Probabilistic Routing Protocol using History of Past Encounters and Transitivity This is for Mrs. Wilson Let me do it. I will probability meet her as usual [Ref: A. Lindgren, A. Doria, and O. Schelen. Probabilistic Routing in Intermittently Connected Networks. ACM Mobile Computing and Communications Review, 2003.] 0.3 S D A B 0.5 X 1.0 0.5 ? A or B ? 0.7 Decision based on delivery probability and transitivity (the probability for a node to encounter a destination) Epidemic Prophet Routing protocol Spray and Focus Mrs. Wilson Spray and Wait
  43. 43. Received messages with different Queue size Prophet has higher received messages than Epidemic Number forwarded messages with different Queue size Prophet has lower overhead than Epidemic 100m 50m 100m 50m Epidemic Epidemic Prophet Simulation parameters Simulation area: 1500 x 300 m Number of nodes: 50 Mobility model: Random Waypoint Epidemic Prophet Prophet Epidemic Prophet
  44. 44. 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) Spray and Wait: Efficient Routing in Intermittently Connected Mobile Networks: The Multiple-copy Case This is for Mrs. Wilson I will spread four copies to first four that I meet, and hopefully it will reach her Spray Phase Source will generate and distribute a small number of copies to only a few relay Wait Phase 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) Epidemic Spray and Wait Routing protocol Spray and Focus Prophet [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.] Mrs. Wilson
  45. 45. Simulation parameters Simulation area: 200 x 200 m Number of nodes: 100, 200 Mobility model: Random Waypoint Epidemic Spray & Wait Spray & Wait Epidemic The number of transmissions for Spray and Wait are very less than Epidemic
  46. 46. This is for Mrs. Wilson 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 Spray and Focus: Efficient Mobility-assisted Routing for Heterogeneous and Correlated Mobility Concept: Limit number of copies made / controlled flooding Goal: To reduce the delay of Spray and Wait [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.] 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) Spray Phase Focus Phase Epidemic Spray and Wait Routing protocol Spray and Focus Prophet Mrs. Wilson
  47. 47. [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.] When the value of TTL increases, the delivery latency decreases Spray and Focus has lower delivery latency than Spray and Wait Spray&Wai t Spray&Foc us 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 Spray&Wai t Spray&Foc us 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
  48. 48. MaxProp: Routing for Vehicle-Based Disruption-Tolerant 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.] This is for Mrs. Wilson My packets are full, and I had the message long enough, and I am sure someone else gave the message to her 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 Epidemic Prophet Spray and Wait Routing protocol Spray and Focus MaxProp
  49. 49. S D C1 C2 C1 C3 Node Mobility Source Destination Can Opportunistic Network support Emergency Scenario? 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.
  50. 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 ]
  51. 51. Future Applications of DTN (OppNet)
  52. 52. OpportunisMc   Network   Weather   Monitoring   Water   Infrastructure   Control   Public   Surveillance   Camera   Abandon their normal daily functions…… and become “helpers” Help to sense fires and flooding Help to sense vehicular movement and traffic jams Help to search for images of human victims During Disaster…. Benevolent OppNet scenario – “Citizens called to arms”
  53. 53. OpportunisMc   Network   Weather   Monitoring   Water   Infrastructure   Control   Public   Surveillance   Camera   Recruit “helpers” to analyze wind patters that can contribute to a faster spread of poisonous chemicals. Help to sense wind patterns Help to sense vehicular movement and traffic jams Help to locate police and military personnel Before City Siege …. Malevolent OppNet scenario – “Bad guys gang up”
  54. 54. Give it to me, I have 1G bytes phone flash. I have 100M bytes of data, who can carry for me? I can also carry for you! Thank you but you are in the opposite direction! Don’t give to me! I am running out of storage. Reach an access point. Internet Finally, it arrive… Search Roar.mp3 for me Search Roar.mp3 for me Search Roar.mp3 for meThere is one in my pocket… Consumer Applications
  55. 55. Hi what’s up? There is a mega sale!! Cool.. I m gonna tell my friend!! Thanks buddy Shopping Malls
  56. 56. Terminal  Bus  A   Terminal  Bus  B  Terminal  Bus  C   Terminal  Bus  D   Synchronize  with  “local  contents”   Smart Transportation
  57. 57. 57 Summary •  Opportunistic Networks (OppNets) are very useful in the context of emergency scenarios •  We discovered that Binary Spray and Wait Protocol is one good option for routing •  Smartphones seems to be a good potential candidate communications tool in emergency scenarios •  Speedier nodes (vehicles) require smaller Message size (images rather than videos).
  58. 58. Future Work •  Requires actual datasets (emergency scenarios) for mobility model •  Mixed mobility scenarios (pedestrians plus vehicles) •  Find better battery efficient methods •  Further refinements to Spray & Wait Protocol with other parameters such as Contact Time etc. •  Implementation on smartphones – e.g. WiFi Direct 802.11ac or Bluetooth
  59. 59. EMAIL: mazlan@gmail.com LINKEDIN: my.linkedin.com/in/mazlan/ TWITTER: mazlan_abbas SLIDESHARE: www.slideshare.net/mazlan1 FACEBOOK: www.facebook.com/drmazlanabbas

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