An information Driven Sensornet Architecture

1. An information Driven Sensornet Architecture Eli.DePoorter@intec.ugent.be www.ibcn.intec.ugent.be INTEC Broadband Communication Networks (IBCN) Department of Information Technology (INTEC) Ghent University – IBBT Department of Information Technology – Broadband Communication Networks (IBCN)

2. Overview • Introduction • An information driven architecture • Example • What more can we do? • Performance • Conclusions

3. WSN: increasingly complex Wireless sensor network Sensor and actuator network • Typical problems when designing a protocol: • Increasingly complex protocols • Lots of (duplicate) functionality • Difficult to combine existing protocols • Many protocol interactions: • QoS, energy-efficiency, etc. Department of Information Technology – Broadband Communication Networks (IBCN)

4. Architecture for WSNs System architecture • Traditionally: layered architecture • BUT: does not cope with WSAN challenges such as: heterogeneity, QoS, ease-of-configuration, easy management, mobility, etc. Global optimizations Heterogeneity Protocol integration Protocol 1 Protocol 2 Department of Information Technology – Broadband Communication Networks (IBCN)

5. Going back to the beginning… Network protocol = Algorithm • Single function • Information exchanges with other nodes • Interacting with passing information Information driven approach: redefinition of the role of protocols! Network protocols in practice: • Buffer provisioning • Design of header fields • Network information gathering • Multiple functions Repeated for each protocol layer! Department of Information Technology – Broadband Communication Networks (IBCN)

6. Overview • Introduction • An information driven architecture • Example • What more can we do? • Performance • Conclusions

7. Information driven approach (2) System information Protocols Information parameter to destination node Create new packet Parameter Exchange Protocol 1 Protocol 2 … Protocol k Department of Information Technology – Broadband Communication Networks (IBCN)

8. Information driven approach System information Protocols Information parameter to destination node Create new packet Parameter Exchange Protocol 1 Protocol 2 … • Protocols only exchange information parameters with the system • The system creates a packet destined to the corresponding destination • The system extracts relevant information from received packets Protocol k Department of Information Technology – Broadband Communication Networks (IBCN)

9. Information driven approach (2) System information Protocols Information parameter to destination node Create new packet Parameter Exchange Protocol 1 Packet façade Packet parameter for controlling and routing a packet Protocol 2 Interact with existing packets … Protocol k Department of Information Technology – Broadband Communication Networks (IBCN)

10. Packet structure Packet parameters are added through a ‘packet façade’ Add parameter Examples: • Routing updates the ‘Next-hop’ parameter • MAC adds a ‘QoS’ parameter Protocol 1 Create packet Decoupling of the protocol logic and packet representation Protocol 2 … Advantages: • Simpler protocols • Reuse of parameters between protocols • Packet type can easily be changed (6lowpan, IEEE802.15.4, legacy support) Protocol k Department of Information Technology – Broadband Communication Networks (IBCN)

11. Shared packet queue Traditional queues Advantages: • Less total queue memory required (queue occupation is averaged) • No copying of packets • Simpler protocols • Easier management and monitoring of the packets Shared packet queue Protocol 1 packets Protocol 2 … The system stores all packets in a shared queue Protocol k Department of Information Technology – Broadband Communication Networks (IBCN)

12. Summary Information Driven Architecture: 3 key concepts • Protocols generate information, not packets • Interaction with packets through a ‘packet façade’ • Single shared packet queue Protocol 1 Protocol 2 … Protocol = Information exchanges with other nodes Interaction with packets Protocol k + Department of Information Technology – Broadband Communication Networks (IBCN)

13. Overview • Introduction • An information driven architecture • Example • What more can we do? • Performance • Conclusions

14. Overview • Introduction • An information driven architecture • Example • What more can we do? • Dynamic protocol selection • Energy efficiency • QoS • Dependencies • Performance • Conclusions

15. Dynamic protocol selection Advantages: • Protocols are ‘plugged into the system’ • Run-time insertion of protocols possible • With filters, they describe for which packet types they are suited • Dynamic run-time selection of the best routing/MAC protocol Protocol stack per application requirement Module per application requirement Department of Information Technology – Broadband Communication Networks (IBCN)

16. Energy efficiency Layered legacy Data aggregation • Information and packets are black boxes • Which information can be combined? New opportunities: global aggregation • Each information exchange with the system includes an ‘acceptable delay’ • Information parameters remain in a ‘waiting space’ • On each node, parameters with the same next-hop or destination are combined Department of Information Technology – Broadband Communication Networks (IBCN)

17. PacketIN Architectural aggregation Shared queue Classifier (Destination) priority SubscribingApplication Parameter Sending Waiting Space Subscribing Protocol 1 Subscribing Protocol k PacketOUT Energy efficiency (2) Global aggregation: • On each node, parameters with the same next-hop or destination are combined Advantages: • Multiple parameters per packet • Combines ANY information parameter, not just measured data • The protocols decide on acceptable delay (not the system) • Can be combined with any routing / MAC protocol Department of Information Technology – Broadband Communication Networks (IBCN)

18. QoS Layered legacy • Protocol must provide QoS per-layer • No system-wide QoS can be enforced Global QoS enfor-cement New opportunities • Buffers are managed by the system • The system selects which packet must be processed Examples • Reorganize the packet order to select: • which packet is processed first • which packet is transmitted first • Drop packets • Enable aggregation on a per-packet base

19. Overview • Introduction • An information driven architecture • Example • What more can we do? • Performance • Conclusions

20. Implementation • Fully implemented in TinyOS • Thoroughly tested • API available • Multiple protocols are already available • MAC • S-MAC, LPL MAC, FlexMAC • Routing • Broadcast protocol, Collection Tree Protocol, DYMO, HYDRO • Available packet implementations • Parameter list, IEEE802.15.4, 6lowpan • Tested on • Office sensor testlab ‘WiLab.T’ • 200 nodes

21. Memory footprint • …of the architecture (without protocols) • ROM: 20 kB • RAM: 6 kB • Total memory of a typical sensor node • ROM: 48 kB • RAM: 10 kB Significant initial investment

22. Memory footprint • … of the protocols Information- driven protocols Traditional protocols * = using our architecture

23. Energy efficiency Scenario: • 30 nodes • Nodes send • Temperature info to a sink (every 10 seconds) • Status info to neighbors (every 30 seconds) Department of Information Technology – Broadband Communication Networks (IBCN)

24. System efficiency Scenario: • 30 nodes • Nodes send • Temperature info to a sink (every 10 seconds) • Status info to neighbors (every 30 seconds) No aggregation Full aggregation Department of Information Technology – Broadband Communication Networks (IBCN)

25. Overview • Introduction • An information driven architecture • Example • What more can we do? • Performance • Conclusions

26. Conclusion • An information driven architecture • Packet façade for creating packets • Dynamic protocol selection • System support for • Energy-efficiency • QoS • Small protocols • Tested on a testbed of 200 nodes • Strong implementation base • Network protocols • Packet structures • QoS • Additional examples are available

27. Questions ? Eli De Poorter Eli.DePoorter@intec.ugent.be www.ibcn.intec.ugent.be INTEC Broadband Communication Networks (IBCN) Department of Information Technology (INTEC) Ghent University - IBBT Department of Information Technology – Broadband Communication Networks (IBCN)