This document describes a complete communications specification, encompassing layers 1 to 4 of the Open Systems Integration (OSI) network model, for a secure, wireless mesh communications network, using open standards communications and cybersecurity standards from standards organizations including Institute of Electrical and Electronics Engineers (IEEE) and Internet Engineering Task Force (IETF). The specification describes the functionality of the physical (PHY layer), medium access control (MAC layer), the network layer, transport layer and security parameters including certificate format for a highly scaleable and secure wireless mesh network for critical infrastructure ipv6 wireless communications networks.

This document defines the technical implementation and behavior of a Wi-SUN Field Area Network which fulfills the marketing requirements specified in [MRD]. With the details presented in this document, an implementer is enabled to construct an interoperable and certifiable implementation of the Wi-SUN FAN.