CSE 5392 Sensor Network Security

1. CSE 5392 Sensor Network Security Introduction to Sensor Networks By Dr. Donggang Liu

2. Communication and processing module sensor An Application of Sensor Networks 1. Network protocol (e.g., routing) 2. Data management (e.g., aggregation) 3. Localization and time synchronization 4. Energy management, robustness, etc. By Dr. Donggang Liu

3. Sensor Node: Mica2 • Hardware • Processor: Atmega128L 4Mhz, 8-bit • Memory: 4K RAM, 512kB Flash • Communication: 19.2kbps Radio • Power supply: 2 AA Batteries • Software • TinyOS / NesC Applications • Network management • Power management • Sensor drivers • Security package (TinySec) By Dr. Donggang Liu

4. Sensing Capabilities • Many types of sensors that are able to monitor: • Temperature • Humidity • Light • Pressure • Noise levels • The presence or absence of certain kinds of objects • Movement (speed, direction) of an object By Dr. Donggang Liu

5. Military Applications • Battlefield surveillance • Monitoring friendly forces, equipment and ammunition • Reconnaissance of opposing forces and terrain • Target tracking • Battle damage assessment • Nuclear, biological and chemical attack detection and reconnaissance By Dr. Donggang Liu

6. Civilian Applications • Forest fire detection • Biocomplexity mapping of the environment • Flood detection • Precision Agriculture: the pesticides level in the drinking water, soil erosion, and air pollution. • Smart environment, smart kindergarten, and more By Dr. Donggang Liu

7. Features of Sensor Networks • Fault tolerance • Scalability • Production costs • Hardware constraints • Sensor network topology • Transmission media • Power consumption By Dr. Donggang Liu

8. Fault Tolerance • Failures due to: • lack of power • physical damage in harsh environment • Interference by other objects (e.g. radios) and other sensors. • Fault tolerance: the ability to maintain sensor network functionalities in the presence of failures • The environment is important to the fault tolerance of algorithms and protocols By Dr. Donggang Liu

9. Scalability • Number of sensors: hundreds, thousands, to millions, depending on the applications. • The density of the network usually depends on the applications • Typically, people consider a large number of sensor nodes densely deployed in a target field. By Dr. Donggang Liu

10. Costs • Per node cost is important for large sensor networks. It has to be kept low. • Bluetooth radio system: $5 now, but still too expensive for sensors. PicoNode: targeted to be < 50c. • More challenging, with large amount of functionalities • Reality: $150 for one Micaz mote By Dr. Donggang Liu

11. Resource Constraints (Mica2) • Processor:8-bit 4MHz CPU (no division) • Limited memory: 4K RAM • Low bandwidth: 19.2K bps • Small packet size: 29-byte long payload • Limited energy supply: Battery powered • Many traditional techniques are not practical By Dr. Donggang Liu

12. Network Topology • Sensor networks are usually formed in an ad hoc manner • Topology maintenance is a challenging task due to • Number of nodes, failures, dynamics etc • Pre-deployment and deployment phase • Reduce the installation cost, • Eliminate the need for any pre-organization and pre-planning • Increase the flexibility of arrangement • Provide better self-organization and fault tolerance. • Post-deployment phase • Topology may changes are due to node movement, lack of energy, node malfunctioning, etc • Re-deployment of additional nodes phase • Adding new sensors By Dr. Donggang Liu

13. Transmission media • Wireless communication • Radio • Infrared • Optical media • Multi-hop communication • Short distance wireless links • Unreliable • Low bandwidth, low power By Dr. Donggang Liu

14. Power consumption • The lifetime of a node strongly depends on the battery lifetime • Sensing, communication, and data processing. • Sensing power: depends on applications • Communication: expensive • Involves both data transmission and reception • The active power + the start-up power consumption • Data processing: not expensive • In-network processing is crucial to minimize power consumption in a multi-hop sensor network. By Dr. Donggang Liu

15. Communication Architecture By Dr. Donggang Liu

16. Protocol Stack By Dr. Donggang Liu

17. Physical Layer • Wireless radio signals • Frequency selection • Frequency generation • Signal detection • Modulation. • Examples: • CC1000 chipset in Mica2 By Dr. Donggang Liu

18. Data Link Layer • Media access control • Provide fair and efficient access to the channel • It provide point-to-point link • Example: CC1000RadioIntM.nc • Error Control • Simple error correction scheme • CRC check • Example: RadioCRCPacket.nc • Energy aware By Dr. Donggang Liu

19. Network Layer • Routing (infrastructureless network) • Ad hoc routing techniques (e.g., DSR) do not fit • Power efficiency • Data centric routing • Data aggregation • Example: • Flooding: each node receiving a packet repeats it by broadcasting (simple flooding versus TTL-based) • Geographic forwarding: forward packets to the nodes close to the destination node • Energy aware By Dr. Donggang Liu

20. Transport Layer • An open research issue • This layer is especially needed when the system is planned to be accessed through Internet or other external networks. By Dr. Donggang Liu

21. Application Layer • An open research issue • Depends on applications: • Makes the hardware and software of the lower layers transparent to the applications By Dr. Donggang Liu

22. A Simple Protocol Stack A simple send/receive application send receive control CC1000RadioIntM.nc CC1000ControlM.nc By Dr. Donggang Liu

23. Active Research Area • Routing • Topology management • Data management • MAC protocols • Target tracking, service discovery • Monitoring and maintenance • Security and privacy By Dr. Donggang Liu