Depth-First Forwarding in Unreliable Networks (DFF)
This document specifies the "Depth-First Forwarding" (DFF) protocol for IPv6 networks, a data forwarding mechanism that can increase reliability of data delivery in networks with dynamic topology and/or lossy links. The protocol operates entirely on the forwarding plane, but may interact with the routing plane. DFF forwards data packets using a mechanism similar to a "depth-first search" for the destination of a packet. The routing plane may be informed of failures to deliver a packet or loops. This document specifies the DFF mechanism both for IPv6 networks (as specified in RFC2460) and in addition also for LoWPAN "mesh-under" networks (as specified in RFC4944). The design of DFF assumes that the underlying link layer provides means to detect if a packet has been successfully delivered to the next hop or not. It is applicable for networks with little traffic, and is used for unicast transmissions only.