The Contiki netstacks
Three network stacks
The Contiki netstack
1. Network layer
2. MAC (Medium Access Control) layer
3. RDC (Radio Duty Cycling) layer
4. Radio layer
Network & Routing Layer
Contiki automatically forms a wireless IPv6 network with the help of routing protocol called RPL (Routing Protocol for Low-power and Lossy Networks (LLNs)).
RPL forms routing graph from root node or AP (Access Point). It builds acyclic graph from root node called DODAG (Destination Oriented Directed Acyclic Graph).
DIO (DODAG Information Object) messages are broadcast by all nodes starting from the root node. It includes the node's rank, ETX, etc.
The node selects a parent based on the received DIO messages and calculates its rank.