Commissioning is a process of establishing a trusted relationship between a new device and the existing IoT system. The operation is divided in two parts:

Joining - This is a process of making a physical connection between a Bluetooth Smart Node and a Bluetooth Smart 6LoWPAN Enabled Router.
Provisioning - This is device activation at the application level with the Cloud.

Here we give an introduction to Joining.

Each example application in this SDK supports commissioning with the local router. If you choose not to enable commissioning, the applications will advertise with the IPSP service and can manually connect to the network.

The IoT SDK comes with a solution for each part of commissioning:

Node role - This is the commissioning library. The nRF52 commissioning library is explained in Commissioning.
Edge Router - A daemon for the Linux based system. The Linux based router daemon to manage the BTLE-6LoWPAN connection is described in Router daemon.
Trusted Third Party device - A phone application for the Android system. The mobile phone application used as a commissioner is explained in the Mobile phone commissioner.

See Running an example application with commissioning to see how to run a commissioning example on an nRF52 kit.