Routing in Wireless Sensor Networks


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Academic Research Presentation: Routing Protocols in Wireless Sensor Networks

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Routing in Wireless Sensor Networks

  1. 1. Elet-6316: Routing Algorithms & Protocols Dr. Driss Benhaddou By: Syed Ashar Zia
  2. 2.  Phase I: Introduction to Wireless sensor networks, its applications, architecture, and challenges. Phase II: Routing Protocols introduction, DSDV, AODV, Cluster-based routing. Phase III: Performance evaluation of AODV and DSDV through BY: SYED ASHAR ZIA 2
  3. 3.  WSN refers to a network of sensor nodes connected through wireless medium. WSN is usually a large network connecting even more than a thousand nodes. Sensor nodes are used to monitor, record and notify specific conditions at various locations. Conditions could be temperature, humidity, wind, pressure, an BY: SYED ASHAR ZIA 4
  4. 4.  WSN has a wide range of applications, such as:  Military applications,  Environmental monitoring,  Industrial sensing,  Security applications. WSN is very useful for monitoring remote locations where human access is limited or not possible at all. BY: SYED ASHAR ZIA 5
  5. 5. BY: SYED ASHAR ZIA 6
  6. 6. Fig: Sensor Network with Internet access BY: SYED ASHAR ZIA 7
  7. 7.  Sensor nodes/End nodes  Responsible for sensing the conditions. Base Station/Sink node  Collects information from end-nodes. Gateways Processing Hub  Processes the collected data at BS. Storage Hub BY: SYED ASHAR ZIA 8
  8. 8. BY: SYED ASHAR ZIA 9
  9. 9.  Three layers are added in TCP/IP model.  To increase the awareness at the nodes.  Task, Mobility & Power are crucial information in sensor networks.BY: SYED ASHAR ZIA 10
  10. 10.  Architecture  Energy efficient architecture is priority.  Compromises could be made on size, capacity, cost & speed. Routing  Different from the traditional IP Networks.  Talking to thousands of nodes makes it complex and inefficient at the energy & storage level. BY: SYED ASHAR ZIA 11
  11. 11.  Distributed Signal Processing  Important part at the low-level layer in WSN.  Provides BS with locations & signal identification of nodes, etc. Storage & Data retrieval  Central storage of data from several nodes.  Storage at nodes requires processing at the nodes. BY: SYED ASHAR ZIA 12
  12. 12.  Actuation  Required action for sensed quantity.  Such as pointing cameras, alarming sounds, opening valves, etc. Security  Attackers may change the behavior of nodes leading to change in results.  Confidentiality, integrity, robustness, and authenticity matters in WSN. BY: SYED ASHAR ZIA 13
  13. 13. Routing in WSN Network Protocol Structure Operation Flat Hierarchical Location Negotiation Multi-path Query QoS basedNetworks Networks based based based based BY: SYED ASHAR ZIA 15
  14. 14.  WSNs are usually ad-hoc in nature. Nodes’ communication directly to BS defines their MANET (Mobile Ad-hoc Network) nature. Set of standards are defined for the protocols used in Ad-hoc networks Mobility of nodes disturbs the standards, therefore routing is quiet challenging. BY: SYED ASHAR ZIA 16
  15. 15. Proactive/Table DSDV, FSR, STAR Driven Hybrid ZRPRouting Protocols for MANET Reactive/ DSR, AODV, TORA On-demand Driven Cluster-based LANMAR, CEDAR BY: SYED ASHAR ZIA 17
  16. 16.  Pro-Active Protocols  Routing table with all paths maintained at each node.  E.g. DSDV (Direct Sequenced Distance Vector) Reactive Protocols  Discovers route when required.  E.g. AODV (Ad-hoc On-demand Distance Vector) Hybrid  Combination of Proactive ZIA Reactive BY: SYED ASHAR & 18
  17. 17.  Each node maintains a routing table containing  List of all available destinations  Number distance to each each destination  Next hop to reach a destination The succession of next hops leads to a destination Each node periodically broadcasts its current estimate of the shortest distance to each available destination to all of its neighbors Typical representative: Distributed Bellman- BY: SYED ASHAR ZIA 19
  18. 18. BY: SYED ASHAR ZIA 20
  19. 19.  Design Goals  Keeping the simplicity of Bellman-Ford.  Avoid looping issues Route information is transmitted by broadcast Updates are transmitted periodically or immediately when any significant topology change is available  Even sequence no.s are assigned by destination  If a broken link is detected: metric ∞ and updated odd sequence no. are assigned by detecting host. BY: SYED ASHAR ZIA 21
  20. 20.  Types of Broadcast updates  Full Dump: All information from the transmitting node.  Incremental: All information that has changed since the last full dump.  Full dump is transmitted if incremental dump exceeds the size of one NPDU. Routing Table is maintained with latest sequence numbered route and least cost metric. BY: SYED ASHAR ZIA 22
  21. 21.  Excellent performance in small networks. Energy efficient as route processing is minimal. Routing overhead is approximately constant regardless of node movements and traffic load. Simple implementation using Bellman- Ford algorithm. BY: SYED ASHAR ZIA 23
  22. 22.  Bandwidth and size of table increases with increasing number of nodes. Overhead increases for maintaining large no. of nodes, hence degrades the performance of network. Fails to converge if nodes are changing locations quickly. Not very efficient in route updating. Limits no. of nodes that can join network. BY: SYED ASHAR ZIA 24
  23. 23.  Intended for the networks with thousands of nodes. It’s a reactive or demand-driven protocol which calculates the route when required and caches it for further use. Routing table only maintains next hop for the destination rather than complete route. Freshness of route is maintained by sequence numbers. BY: SYED ASHAR ZIA 25
  24. 24.  Routing Table maintains:  Destination IP address  Destination sequence number  Valid destination sequence number flag  Other state & routing flags  Network interface  Hop count  Next hop  Lifetime (route expiration time) BY: SYED ASHAR ZIA 26
  25. 25.  Basic message set in AODV includes:  Hello - For link status  RREQ - Route Request  RREP - Route Reply  RERR - Route Error Only in case of Route is not in table and has to be discovered. BY: SYED ASHAR ZIA 27
  26. 26. A B?B? B? B? B? B? B? B
  27. 27. A A A A B
  28. 28.  Maintenance of Routes is handled very efficiently in AODV  Hello messages broadcast by active nodes periodically called HELLO_INTERVAL.  If no Hello reply from a neighbor within DELETE_PERIOD link failure is identified.  RERR message is broadcasted to other neighbors.  Entries based on that node invalidated.  Route is rediscovered using RREQ when it is required. BY: SYED ASHAR ZIA 30
  29. 29. Simulation done by:Abdul Hadi Abd Rahman & Zuriati Ahmad ZukarnainEuropean Journal of Scientific Research
  30. 30. Scenario 1: End-to-End Delay with increasing number of nodes.In AODV graph fluctuates between 0.3 and 2.4sec while in DSDV it is between0.005 and 0.008 sec. This shows that route calculation or discovery method inAODV increases the End-to-End delay. BY: SYED ASHAR ZIA 32
  31. 31. Scenario 2: Routing Overhead with increasing number of nodes.Here, three routing protocols are compared, AODV, DSDV and ImprovedDSDV. Here, we can see that with increasing no. of nodes routing overheadincreases dramatically in DSDV which causes instability when it’s a largenetwork. BY: SYED ASHAR ZIA 33
  32. 32.  Small WSN:  DSDV is better than AODV.  Less routing overhead  Delay is negligible when compared to the time it takes to calculate route in AODV. Large WSN:  AODV is better than DSDV  Efficiently handles mobility and route updates.  Less overhead and appropriate delay. BY: SYED ASHAR ZIA 34
  33. 33.  Routing in Wireless sensor networks – Rachid Ennaji & Muhammad Boulmalf – IEEE, 2009 Performance comparison of AODV, DSDV and I- DSDV – Abdul Hadi & Zuriati Ahmed – European Journal of Sc. Research Group-based clustering RP – Lei Zhang – IEEE, 2007 html SN/projectdescription.html BY: SYED ASHAR ZIA 35
  34. 34. BY: SYED ASHAR ZIA 36