This paper reports on a promising approach for solving problems found when Multi Protocol Label Switching (MPLS), soon to be a dominant protocol, is used in core network systems. Difficulty is found largely in LSP routing and traffic engineering approaches. While there are a number of online and offline proposals to establish the LSPs but no one is a complete solution considering all the aspects of routing plan from traffic engineering point of view. Our research takes a viewpoint inspired by the concept of "between-ness" from graph theory, from which we introduce notions of link and path criticality indexes. The basis of the work is finding the most critical paths which are mathematically defined based on the algebra of routing. We try to avoid running aggregated flows or commodities on the most critical paths for the short term, and plan increasing the bandwidth of the critical paths for future if possible. This approach shows promise in simulations have run on benchmark ne...