Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. One example routing solution to LLN challenges is a protocol called Routing Protocol for LLNs or “RPL,” which is a distance vector routing protocol that builds a Destination Oriented Directed Acyclic Graph (DODAG, or simply DAG) in addition to a set of features to bound the control traffic, support local (and slow) repair, etc. The RPL architecture provides a flexible method by which each node performs DODAG discovery, construction, and maintenance.
One very critical issue faced in LLNs is the high degree of “lossy-ness”, where the percentage of packets dropped can become extremely high, and where the link quality is hardly predictable, such as due to a number of factors, e.g., electro-magnetic interference, noise, etc. Another common reason for packet loss in wireless mesh networks which are used for example in Advanced Metering Infrastructure (AMI) may be a truck or a car which is parked in front of a home and temporarily blocks a specific radio path. For instance, for LLNs established using wireless communication and/or powerline communication (PLC), it is fairly common for links to flap with a very high frequency, and there is generally no way to predict link behavior. For instance, due to the lossy-ness, it is often the case that a node transmitting over a shared media communication to another node may not always reach the intended recipient, or may reach the intended recipient, but may not always receive an acknowledgement (ACK) from the recipient (i.e., the ACK is lost in the return transmission).
USPTO Backgrounds
USPTO Backgrounds