1. A method of reducing, in a network having a plurality of core nodes and a plurality of edge nodes connected by links, the number of duplicate LSAs propagated during a flooding event, said method comprising the steps of: forming an LSA forwarding subgraph wherein the edges of said LSA forwarding subgraph correspond to said links, and said LSA forwarding subgraph comprises the union of a quantity K spanning-trees containing said core nodes and the links connecting said core nodes to said edge nodes, and wherein said K spanning-trees are edge-disjoint, and where within each of the K spanning-trees no core node can have a degree greater than quantity N, and where a core node appears as a node in more than one tree of said quantity of K spanning-trees only insofar that the overall degree of said core node in the K spanning trees is at most a quantity M; and upon a core node in said network receiving an LSA along a first link during said flooding event, said core node forwarding said LSA along only a first subset of links corresponding to edges in said LSA forwarding subgraph; and upon an edge node in said network receiving an LSA along a first link during said flooding event, said edge node forwarding said LSA along only a second subset of links corresponding to edges in said LSA forwarding subgraph.