Data Dissemination in Sensor Networks

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• Data Dissemination in Sensor Networks
• Challenges and Solutions
• by
• Sovrin Tolia

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Presentation Outline

• Overview of Sensor Networks
• Directed Diffusion, A Scalable and Robust
  Communication Paradigm for Sensor Networks
• SPIN, Adaptive Protocols for Information
  Dissemination in Wireless Sensor Networks

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Research Efforts

• Directed Diffusion
• USC/ISI Institute
• Deborah Estrin, Ramesh Govindan et al
• SPIN Protocols
• MIT
• Balakrishnan, Joanna Kulik et al

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Challenges in Sensor Networks

• Sheer Numbers
• Unattended deployment
• Device failures
• Frequent Change
• Heterogenity of Tasks

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Sensor Nodes

• Capability of Sensor Nodes
• Distributed Microsensing
• Sensor Networks are task specific
• Autonomous Operation

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Sensor Network Applications

• Monitoring Remote Geographic Locations and
  terrains
• Toxic Urban Locations
• Less Accessible environments like large
  Industrial Plants and Aircraft Interiors

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Directed Diffusion

• Motivated by Scalability, Energy Efficiency and
  and robustness
• Data Centric
• Application Aware
• Energy Efficient
• Remote Surveillance Sensor Network

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Directed Diffusion

• Naming

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Directed Diffusion

• Interests and Gradients
• Sink Nodes
• Periodic Broadcasts
• Interest Cache in every node (distinct
  interests)
• Two Way Gradient established
• Generalized Interest Propagation means

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Directed Diffusion

• Data Propagation
• location satisfied, finds Interest Match from
  cache
• computes the highest data rate in gradients
  present in the interest cache
• Intermediate Node base their decision based on
  Data cache
• Downconversion

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Directed Diffusion

• Reinforcement
• Data Driven Rules for deciding which node(s) to
  reinforce
• Explicitly send a high data rate Interest
  message
• What do the neighboring nodes do
• Extreme Reactivity and Negative Reinforcements

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Directed Diffusion Explained
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In Essence

• No mention of target detection algos
• The usage is not restricted to interests-gradients
  -drawing data.
• All Communication uses interests to specify named
  data
• Neighbor-Neighbor (Not End-to-End)
• No routers, governed by task specificity
• No Need for globally unique identifiers

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Is It Routing ?

• Kind of Reactive, Routes on Demand
• No Attempt to find one loop free route
• Constrained Flooding is used
• Message Cache is used to avoid loops
• They did carry out some preliminary results

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Future Research here

• Target Detection Algorithm
• Simulate Congestion in the network
• Experiment the non-aggressive reinforcement
  strategy and less conservative negative
  reinforcements
• Sensor Networks are at a stage where Internet was
  three decades ago

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SPIN, Sensor Protocols for Information via
Negotiation

• Overcomes Implosion, Overlap and Resource
  Blindness in conventional approaches
• Advocates Negotiation and Resource-adaptation

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SPIN

• Naming Using Meta Data
• SPIN Messages
• ADV,REQ,DATA
• Resource Management
• Implementation
• 3-stage handshake
• Participation only when it can complete all the
  three stages

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SPIN Working
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SPIN Architecture
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Performance

• Compared against flooding, gossiping and ideal
  protocol
• Metric is amount of data disseminated over time
  and energy consumed
• SPIN-1 higher throughput than gossip but same as
  flooding, less energy usage
• SPIN-2 ideal amount of data per unit energy

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Food for Thought

• If Ad-hoc networks are not yet a reality, can we
  ever expect Sensor Networks to be deployed
• Are they really required ?
• ANY QUESTIONS