1. Nov. 14, 2001CS851 Sensor Network1 Information Service Architecture Weilin Zhong

2. Nov. 14, 2001CS851 Sensor Network2 Outline Distributed Information Services and Architecture Random, Ephemeral Transaction Identifiers (RETRI)

3. Nov. 14, 2001CS851 Sensor Network3 Outline -- ISA Information Service Architecture Sensor Network Applications Information Services in Sensor Network Information Service Architecture (ISA) Critiques

4. Nov. 14, 2001CS851 Sensor Network4 Outline --RETRI Random, Ephemeral TRansaction Identifiers (RETRI) Global vs. Local ID RETRI & Advantages Address-Free Fragmentation (AFF) Theoretical Model Critiques

5. Nov. 14, 2001CS851 Sensor Network5 Distributed Information Services and Architecture for Sensor Network

6. Nov. 14, 2001CS851 Sensor Network6 Applications of Sensor Network Sensor NetworkTraffic Control Terrain Exploration Smart Environment Inventory

7. Nov. 14, 2001CS851 Sensor Network7 Challenges Massive Number of Nodes Spontaneously Deployment Dynamic adaptable and Self-organizing Integrated & Cooperative Service Limited Resources and Capabilities

8. Nov. 14, 2001CS851 Sensor Network8 What does the paper suggest? Lookup Service Composition Service Adaptation Service

9. Nov. 14, 2001CS851 Sensor Network9 Distributed Services Lookup Server Lookup Server Room 236 IDServiceLocation 1TemperatureR236 2LightR236 3NoiseR236 ……… 1 2 3 RegisterAccept/Reject

10. Nov. 14, 2001CS851 Sensor Network10 Distributed Service Discovery Lookup Server B Lookup Server C Service Client Service Provider X Find Service X Service X Location Sensor Cluster Higher-level Cluster Discover Service X Lookup Server A Forward Service Reply Update new Service location information in local cache Checks own registry first before forwarding discovery request Update new service location information in local cache Discover Service X Propagate Service Info Direct end-to-end request for Service X Reject/Accept Register Service X

11. Nov. 14, 2001CS851 Sensor Network11 Discovery for Mobility Nodes Lookup Server B Lookup Server C Service Client Service Provider X Sensor Cluster Higher-level Cluster Lookup Server A Propagate Change in Service X’s location Update new Service location information in local cache Ack of De-Registration De-Register Service X Register Service X Accept/Reject Notify C of Service X’s new location Relocate Notify Change in Service X new Location Uninterrupted use of Service X after service handoff

12. Nov. 14, 2001CS851 Sensor Network12 Compositional Server Node Addition and Removal Network Abstractions Cluster Formation & Hierarchical composition of clusters Sensor Cluster A 2nd-level Cluster B 3rd-level Cluster C Compositional Server A Compositional Server B Compositional Server C Service Abstraction A Composition Service Abstraction B Composition Formation :Cluster Header Service Abstraction C

13. Nov. 14, 2001CS851 Sensor Network13 Compositional Service Temperature Control System Room 101 Floor 1 Building :Cluster Header Room 102 Room 103 Compositional Server of Room Room Average Temperature Composition Formation Compositional Server of Floor Floor Average Temperature Composition Formation Compositional Server of Bldg Building Average Temperature Composition Formation Room Service Abstraction

14. Nov. 14, 2001CS851 Sensor Network14 Adaptation Server Monitor During Normal Execution Schedule reconfiguration operations when needed Compositional Server Lookup Server Adaptation Server Analytical Tools Composite Formation De-register Accept /Reject Dependency Monitor/Reconfigure Compositional Server Lookup Server Adaptation Server Analytical Tools Composite Formation Register Accept /Reject Dependency Monitor/Reconfigure relocate

15. Nov. 14, 2001CS851 Sensor Network15 Adaptation Service Temperature Control Lookup Server IDServiceLocation 1TemperatureR101 2TemperatureR101 3TemperatureR101 Compositional Server Average Temp with 90% Confidence Level Accept/Reject 100 samples/sec Integrated Adaptation Server Monitoring Sampling 33 times/sec

16. Nov. 14, 2001CS851 Sensor Network16 Adaptation Service Temperature Control (Add a node) Lookup Server IDServiceLocation 1TemperatureR101 2TemperatureR101 3TemperatureR101 4TemperatureR101 Compositional Server Average Temp with 90% Confidence Level Accept/Reject 100 samples/sec Integrated Adaptation Server Monitoring Sampling 25 times/sec Register Accept

17. Nov. 14, 2001CS851 Sensor Network17 Information Service Architecture

18. Nov. 14, 2001CS851 Sensor Network18 Application Systems Collaborative Signal Processing :Cluster Header Sub Area Signal Processing Agent Data fusion Mobile Agents Intermediate Integrated Reading Sensor Cluster A 2nd-level Cluster B 3rd-level Cluster C Integrated Reading Integrated Reading

19. Nov. 14, 2001CS851 Sensor Network19 Temperature Control System Room 101 Room 102 Room 103 Database Server Temperature ?= 26 Wherever there is person UserIDNameLocation 1DaveR101 2JackR102 Lookup Server Register Accept Monitoring/Control IDSL 1T101 2T 3T 4T102 5T 6T 7T103 8T 9T Lookup Server Register Accept

20. Nov. 14, 2001CS851 Sensor Network20 Temperature Control System Room 101 Room 102 Room 103 Database Server Temperature ?= 26 Wherever there is person UserIDNameLocation 1DaveR101 2JackR102 Lookup Server Register Accept Where there is a person? R101, R102 Monitoring/Control IDSL 1T101 2T 3T 4T102 5T 6T 7T103 8T 9T Mediator Sub-query (temperature, R102,26) Sub-query (temperature, R101,26) Lookup Server Sensor Lookup Available Sensors & their locations OIDSL 1Ave TR101 2Ave TR102 Object Server Collaborative Processing Agent 1 Collaborative Processing Agent 2

21. Nov. 14, 2001CS851 Sensor Network21 Correct Assumption? Sensor = Service Provider? Problems Identifiable Sensor ( unique ID, Location) Register/De-register each sensor Highly dense sensor network – smart paint Highly dynamic sensor network – traffic control

22. Nov. 14, 2001CS851 Sensor Network22 Correct Assumption? Servers are properly deployed in advance? Problems Static Architecture Hostile Environment – battlefield Moving Sensor Network – smart dust

23. Nov. 14, 2001CS851 Sensor Network23 Critiques Critiques for Distributed Information Services Globally unique identifiers GPS locations are used Register/De-register every sensor at every movement Static and Pre-deployed Architecture Bad scalability

24. Nov. 14, 2001CS851 Sensor Network24 Random, Ephemeral Transaction Identifiers -- RETRI

25. Nov. 14, 2001CS851 Sensor Network25 Outline --RETRI Random, Ephemeral TRansaction Identifiers (RETRI) Global ID vs. Local ID RETRI & Advantages Address-Free Fragmentation (AFF) Theoretical Model Critiques

26. Nov. 14, 2001CS851 Sensor Network26 Why not Global Unique ID? Global Unique ID can be very expensive in Sensor Network Small Data Rate/Size vs. Large Global Unique ID size Highly dynamic vs. Static Assigned Global Unique ID Local Unique ID is desirable Traditional Local ID Central Address Authorities (DHCP) Listening and Scoping (Multicast address allocation)

27. Nov. 14, 2001CS851 Sensor Network27 Basic Idea of this paper Transaction-based ID Reduce the transmission of header bit Header bits transmitted H = 3 bit * 10 packet * 10 trans In Static allocated global ID H = 16bit * 10 packet * 10 trans Great scalability Header bits increased with transaction density instead of number of nodes Temporal and locally unique ID Avoid expensive global Ids ID is reusable Collision is not a concern 1 2 5 4 3 1 2 5 4 3

28. Nov. 14, 2001CS851 Sensor Network28 Address-Free Fragmentation ID AFF Sender Data Packet AFF Receiver ID Data Packet transaction ID AFF Sender Data Packet Collision

29. Nov. 14, 2001CS851 Sensor Network29 Theoretical Model Efficiency Metric E= Useful Bits Received/ Total Bits Transmitted Static Allocation E static = D / ( D + H) Address-Free Architecture E afa = D X P (Success) / (D + H) P(Success) = ( 1 – 1/2 H ) 2(T-1) D: bits of Data H: bits of header ( identifier) T: transaction density T, the average number of concurrent transactions visible at any single point in the network.

30. Nov. 14, 2001CS851 Sensor Network30 Efficiency Curve Optimal Balance Superior with transaction Locality Transaction Density Optimal Balance Bits --- E 169 – 60% 25613 – 52% 64k21 – 40%

31. Nov. 14, 2001CS851 Sensor Network31 Efficiency Curve – Larger Data Size Increasing Optimal Header Length Static Allocation wins Reasons: Larger data size amortizes the cost of static allocation Large data size increase the cost of collisions The cost of collision is higher than the benefits gained from sending less identifier bits.

32. Nov. 14, 2001CS851 Sensor Network32 When AFF is superior? AFF wins Large number of nodes Small transaction density Small data rate/size Lower-power radio and simple MAC protocols => Sensor Network Static Allocation Wins Small number of nodes High transaction density Large data rate/size High-power radio and complex MAC protocols => Ethernet

33. Nov. 14, 2001CS851 Sensor Network33 Critiques of AFF Problems with AFF Hop-to-hop transmission Store and forward model 3 15 Transaction

34. Nov. 14, 2001CS851 Sensor Network34 Questions? Thank You!