A method and apparatus is disclosed for policy-enabled, contract-based management of network operational support systems. In this optical fiber cable, when a Young’s modulus of the sheath at 0\xb0 C. The method includes the steps of: reading graph data S on multiple vertices as search starting points from a storage area of the computer; reading graph data T on multiple vertices as search targets from the storage area of the computer; selecting k vertices s1, s2,.