Simulation of Distributed Application and Protocols using TOSSIM

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Simulation of Distributed Application and
Protocols using TOSSIM

• Valliappan Annamalai

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Traditional system
Wireless Transceiver
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Sensor Systems

• Sensor applications developed on top of TinyOS.
• TinyOS similar to traditional OS but light
  weight.
• Some of the services provided by TinyOS
• Transmit and receive a packet wirelessly.
• LED for displaying to display output.
• Accessing storage (Flash) etc.
• Application specific. So only one application is
  loaded onto each sensor.
• TinyOS component-based OS

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TinyOS Components

• Provide services.
• Services are accessed via interfaces.
• Interfaces defines functions used for accessing
  services (e.g. Timer, SendMsg, RecvMsg).
• Function calls
• Blocking
• Non-blocking

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Split-phase operation

• In TinyOS all function calls are non-blocking.
• Example Sending packets.
• Application sends data by invoking a function
  called send.
• Transmission of packet is a long latency
  operation.
• Long latency operations are grouped into a
  function called Task which is scheduled for
  execution when CPU is idle.
• So packet is scheduled for later transmission and
  send immediately returns.
• After transmission TinyOS notifies the
  application by invoking a callback function
  implemented by the application.
• ? Two way communication between components.

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Commands Events

• Interfaces define both the functions for
  accessing the service and the call back functions
  (enables two-way communication between
  components).
• Commands Functions invoked to access a service.
• Events Callback functions.
• Component providing an service via an interface
  will have command definition.
• Component using an interface will have event
  definition.
• Example
• Command start of Timer
• Event fired of Timer

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Interface Example Timer

• interface Timer
• command result_t start(char type, uint32_t
  interval)
• command result_t stop()
• event result_t fired()

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TinyOS Application

• Will contain at least one component called
  configuration and might contain another component
  called Module.
• Configuration Defines how TinyOS components are
  connected to the Application (Wiring).
• Module Application specific code.
• Example Blink Application.
• Configuration Blink.nc
• Module BlinkM.nc
• Each application provides stdcontrol interface.

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Main Component

• Entry point into application.
• Starts a scheduler queue (FIFO) for Tasks.
• Passes control to application component through
  start command of stdcontrol interface provided by
  application.
• Two threads of execution
• Scheduler for tasks
• Commands and events

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Wiring of components Blink Component
Entry point
Main
stdControl Interface BadgeM implements stdControl
interface
BlinkM
Timer Interface TimerC provides the interface
for Setting timer interrupt parameters BadgeM
implements the event handler for fired event
Led interface for turning on and off LEDS
SingleTimer
All wirings Below this are predetermined
Clock Interface HPLClock provides the interface
for Setting timer interrupt parameters TimerC
implements the event handler for fired event
HPLClock
Set Interrupt Specific parameters
ISR calls clock fired Event handler
Hardware Clock
Leds
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Event and Commands in BlinkM
stdcontrol Interface
Command
Main
Event
Starts FIFO
Function
stdcontrol Interface
Start
Start
Tasks
BlinkM
FIFO Scheduler
Fired
Start
Timer Interface
Leds Interface
SingleTimer
setInterval
Fired
HPLClock
RedToggle
Fired
Clock ISR (TOSH_INTERRUPT)
Leds
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TOSSIM

• Simulator to test sensor network applications.
• Distributed systems are hard to debug.
• Before actual deployment TOSSIM can be used to
  debug developed application on a large sensor
  network.
• No specific modification to application code.
• Application compiled for TOSSIM will the
  simulator code too.
• Run the exe file and pass the number of nodes to
  be simulated as the parameter.

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Programming Assignment I

• Develop an application for the flooding-based
  tree construction protocol that we discussed in
  class on TinyOS using NesC and simulate it using
  TOSSIM
• Things you should know
• Basic NesC programming language constructs
• How to transmit and receive user defined packets
  using the services provided by the communication
  component in TinyOS?
• How to use TimerM component?
• How to compile the application for TOSSIM?
• How to display the output in TOSSIM?

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Deliverables

• Soft copy of your application's configuration
  file.
• Soft copy of your application's module file
• Soft copy of the header file with packet
  definitions and AM message type definitions
• A document that details the working of your
  application. Also should contain the difference
  in the routing tree, if any, when the lossy and
  the simple radio model are used. Also include the
  amount of time it took you to complete each of
  the steps mentioned above and the task.
• Zip file which contains all these files. Name the
  zip file using your lastname_firstname.

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Estimated Time for Assignment

• Step 1 2 Hours
• Step 2 8 Hours
• Step 3 2 Hours
• Step 4 1 Hour
• Task 5 Hours
• Total 18 Hours