1. A method of implementing a Shortest Path First (SPF) computation, comprising: identifying a plurality of network elements connected together as a distributed network; identifying one or more predetermined events occurring in a status of one of the plurality of network elements in the distributed network under a link state protocol (LSP); and implementing, by a processor, the SPF computation only for a multicast distribution in the distributed network except when the identified one or more predetermined events trigger a change in the LSP, wherein the one or more identified predetermined events includes a change in a distribution tree.