Patent ID: 8037023

Claim:
A method for updating replicated data stored in a plurality of nodes organized in a hierarchy and linked through networks, the method comprising: defining a freshness threshold for any replicated data stored at any given node within the network hierarchy of nodes, the freshness threshold comprising a maximum elapsed time from generation of any original data summary from which replicated data are copied; and determining an update period across each one of a plurality of links between the nodes in the network hierarchy for replicated data stored at each node such that the freshness threshold is satisfied for all replicated data stored at any given node and overhead associated with updating replicated data is minimized by: maintaining state data at each node within the hierarchy of nodes, the state data at a given node comprising: a current data update period associated with that node and expressing the period at which its parent node should send a data update; and a summation of the data update periods from its parent node to any descendent leaf node of that node; and maintaining at each non-leaf node a scale factor associated with each child node of the non-leaf node; and updating replicated data stored at the nodes in accordance with the determined update periods, wherein the plurality of nodes are arranged in a tree hierarchy.