We propose a system architecture for a customer network management (CNM) agent for public asynchronous transfer mode (ATM) networks. The main feature of this system is that it can mediate between the Internet (TCP/IP network) management framework and the telecommunication management network (TMN) framework. This will enable customers to achieve end-to-end network management of their enterprise network. We present some key solutions, including propose two approaches to its implementation: management information base (MEB) acquisition and effective MIB mapping. This system architecture can be applied not only to end customers but also to other service providers, including outsourcers and resellers.