1. A method for performing an efficient constrained shortest path first (CSPF) optimization of Traffic Engineering (TE) Label Switched Paths (LSPs) in a computer network, the method comprising: detecting an event in the computer network that could create a more optimal path for TE-LSPs; selecting a root node based on its adjacency to the event and its location along a particular TE-LSP; and performing a CSPF computation for the particular TE-LSP rooted at the root node.