This document describes a Simplified Multicast Forwarding (SMF) mechanism that provides basic Internet Protocol (IP) multicast forwarding suitable for limited wireless mesh and mobile ad hoc network (MANET) use. It is mainly applicable in situations where efficient flooding represents an acceptable engineering design trade- off. It defines techniques for multicast duplicate packet detection (DPD), to be applied in the forwarding process, for both IPv4 and IPv6 protocol use. This document also specifies optional mechanisms for using reduced relay sets to achieve more efficient multicast data distribution within a mesh topology as compared to Classic Flooding. Interactions with other protocols, such as use of information provided by concurrently running unicast routing protocols or interaction with other multicast protocols, as well as multiple deployment approaches are also described. Distributed algorithms for selecting reduced relay sets and related discussion are provided in the appendices. Basic issues relating to the operation of multicast MANET border routers are discussed, but ongoing work remains in this area and is beyond the scope of this document.