Patent ID: 8750100

Claim:
A method for avoiding a broken link in a network of smart meters and concentrators when routing packets between the smart: meters and the concentrators, wherein the smart meters and concentrators are connected by commnication links, comprising the steps of: representing the network by a Destination Oriented Directed Acyclic Graph (DODAG), wherein nodes in the graph represent the smart meters and concentrators, and the concentrators are root nodes roots in the DODAG, and directed edges represent the links; and associating each node with a rank, wherein the rank defines a position of each node relative to other nodes and with respect to the root of the DODAG, and wherein the root has a lowest rank of all the nodes in the DODAG, and the nodes maintain the ranks based on a parent-child relationship in which each child must have a rank strictly greater than all the ranks of parents of children, and the root has no parent, and wherein the rank is in a form of a proper fraction, and wherein the rank of each node never increases even if the broken link is detected to enable loop-free routing, defining the rank R(i)=(m, n) for a node i as R(i)=m/n, where 0≦m≦n, m and n are integers, and 0<n; and defining for any two ranks R(i)=(m, n) and R(j)=(p, q) as split operation as sp(R(i), R(j))=sp ((m, n), (p, q))=(m+p)/(n+q) so that the split operation sp(R(i), R(j)) splits rank (m, n) and (p, q), and generate a new rank (m+p)/(n+q), and if m/n<p/q, then m/n<(m+p)/(n+q)<p/q, wherein the steps are performed in processors in the smart meters and concentrators.