Recently, SLAs become an important issue considered in the next generation telecommunication services. The subscriberspsilas perspective drives ISPs eager to support their requirements by offering SLAs across domains. Under deregulatory environment, this paper has adopted a path-classification scheme in order to capture the freedom of policy selection. To prevent selfish path provisioning in the interdomain network, we propose the utility function that includes the penalty term. By means of Nash equilibrium, the equilibrium policy has been found with searching algorithm by applying the modified MSA. We investigate the equilibrium based on the proposed utility functions according to business relationships, namely, peer, wholesale and retail services. The experimental results show that the equilibrium policy leads ISPs to act as non-selfish behavior and to achieve high system performance.