One of the main features of Contiki-NG is a resource-efficient IPv6 network stack designed for lossy and low-power networks. The network stack comprises protocols such as IPv6, TCP, UDP, DNS, RPL, CoAP, LWM2M, and Websockets. Beneath the IPv6 stack, Contiki-NG supports IEEE 802.15.4 wireless communication with Time-Slotted Channel Hopping (TSCH).
Module-specific documentation below:
You might also want to read the packet buffers documentation.