1. Main Issues Three major issues that we are concerned with in sensor networks are – Clustering Routing and Security To be considered against the backdrop of strict hardware constraints

2. Security Ensuring that the communications are secure (Particularly important in military applications) Clustering Dividing the network into clusters after deployment, and choosing a cluster head Routing Deciding routing paths for communication between the base station and the cluster heads

3. Goals Implement clustering, routing, and security algorithms developed by the team Run test cases for different parameters of a sensor network For example number of nodes in the network, number of clusters Run different test cases for ‘abnormal’ conditions to check the robustness of the algorithms For example a cluster head dying out without being able to inform other cluster members

4. How do we do this ?

5. …simulation

6. The software TinyOS TinyOS is a component-based runtime environment designed to provide support for deeply embedded systems which require concurrency intensive operations while constrained by minimal hardware resources --- TinyOS website at UC Berkeley The programming language – nesC, a programming language for Network Embedded Systems

7. nesC Application A NesC application consists of one or more components, linked together to form a runnable executable. Component Components are the basic building blocks for NesC applications. Components are of two types: modules and configurations. Module A module is a NesC component consisting of application code in a C-like syntax. Configuration A configuration is a component that "wires" other components together. Every NesC application has a single top-level configuration that specifies the set of components in the application and how they invoke one another.

8. Configuration Module 1Module 2Module n

9. TOSSIM TOSSIM - The TinyOS simulator Allows nesC code to be compiled and executed on a Linux machine Even has a simple GUI to it

10. Example Simulation Consider two motes (ID 0 and1) communicating with each other as follows: Mote 0 maintains a 16-bit integral counter, and at every tick of the counter it broadcasts the value of the counter across it’s RF communication channel to Mote 1

11. Example Simulation The format of the data transmitted/received over the radio channel typedef struct TOS_Msg { /* The following fields are transmitted/received on the radio. */ uint16_t addr; uint8_t type; uint8_t group; uint8_t length; int8_t data[TOSH_DATA_LENGTH]; /* The following fields are not actually transmitted or received * on the radio! They are used for internal accounting only. * The reason they are in this structure is that the AM interface * requires them to be part of the TOS_Msg that is passed to * send/receive operations. */ uint16_t strength; uint8_t ack; uint16_t time; } TOS_Msg;

12. Example Simulation

13. Format of data MoteData 0ff ff 04 7D 08 04 00 00 MoteData 1ff ff 04 7D 08 04 00 00 ff ff= addr (broadcast) 04= type (handler ID) 7D= group (cluster ID) 08= length 040000= Data

14. Thank You Questions ?