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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. Main Issues. Security Ensuring that the communications are secure
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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 Main Issues
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
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 Goals
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 The software
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.
Configuration Module 1 Module 2 Module n
TOSSIM • TOSSIM - The TinyOS simulator Allows nesC code to be compiled and executed on a Linux machine Even has a simple GUI to it
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
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;
Format of data Mote Data 0 ff ff 04 7D 08 04 00 00 Mote Data 1 ff ff 04 7D 08 04 00 00 ff ff = addr (broadcast) 04 = type (handler ID) 7D = group (cluster ID) 08 = length 040000= Data
Thank You Questions ?