NS-3 does not have built-in RPL (Routing Protocol for Low-Power and Lossy Networks) support. The ns3/rpl-helper.h file doesn't exist in the standard NS-3 distribution.

What's Available:

No Official RPL Module - The main NS-3 repository doesn't include RPL implementation

Third-Party Implementations - You need to find and integrate external RPL modules

Solutions:

Use NS-3 with Contiki Integration:

Use NS-3 with Contiki OS simulation

Contiki has native RPL support

This requires more complex setup but gives you real RPL behavior