RFC 7228 further says, Low-Power and Lossy Network often exhibit considerable loss at the Physical Layer, with significant variability of the delivery rate, and some short-term unreliability, coupled with some medium-term stability that makes it worthwhile to both construct directed acyclic graphs that are medium-term stable for routing and do measurements on the edges such as Expected Transmission Count (ETX) RFC 6551. Not all LLNs comprise low-power nodes RPL-DEPLOYMENT.
Low-Power and Lossy Networks typically are composed of Constrained Nodes; this leads to the design of operation modes such as the "non-storing mode" defined by RPL (the IPv6 Routing Protocol for Low-Power and Lossy Networks RFC 6550). So, in the terminology of the present document, an LLN is a Constrained Node Constrained Network with certain network characteristics, which include constraints on the network as well.