RPL objective function modification and simulation in cooja

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Introduction

The Routing Protocol for Low-Power and Lossy Networks (RPL) builds a Destination Oriented Directed Acyclic Graph (DODAG) using the Objective Function (OF). The Objective Function uses some routing metrics to form the DODAG based on some algorithm or calculation formula. Basically objective functions optimize or constrain the routing metrics that are used to form the routes and hence help in choosing the best route. There could be many objective functions in operation on the same node and mesh network because deployments vary greatly with different objectives and a single mesh network may need to carry traffic with very different requirements of path quality.

The Contiki implementation of RPL, there are 2 objective functions, but by default it uses the one that minimizes the ETX values. But the same cannot be the best strategy in all routing scenarios. Hence there arises a need to modify the objective function accordingly to accommodate any additional constraints or to achieve a different objective.

You Will learn

• Different RPL related functions and their working
• Modifying an existing RPL objective function
• Simulation in Cooja using DGRM model

Cooja Simulation using DGRM model

The following are the steps to form a new simulation:

• Run Cooja

cd to your Contiki folder and then cd to /tools/cooja run the command sudo ant run to open up a cooja GUI

• Start a New Simulation

Choose a new Simulation from the File drop down menu (or alternatively can do Ctrl+N).

References

Edited by - Ashwini Telang

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