Policy-based Network Management (PBNM) has been presented as a paradigm for efficient and customizable management systems. The approach chosen is based on PBNM systems, which are a promising and novel approach to network management. These systems have the potential to improve the automation of network management processes. The Internet Engineering Task Force (IETF) has also used policy concepts and provided a framework to describe the concept as the Policy Core Information Model (PCIM) and its extensions. There are policy conflicts among the policies that are defined as the policy information model and they are not easily and effectively detected and resolved. In this paper, we present the brief description of PBNM and illustrate the concepts of policy core information model and its policy implementation for a network security. Especially we describe our framework for detecting and resolving the policy conflicts for network security.