In this paper, we propose a new architecture of the global communication networks, the Dynamic Networking Architecture. In the proposed architecture, a new network middleware called Flexible Network Layer (FNL) is introduced between the application layer and the transport layer to enhance the capabilities of communication networks by dealing with various changes detected in human users, applications, platforms and networked environment. To realize the FNL, we adopt an agent-based computing framework as a software infrastructure to develop and manage various components and related knowledge of the FNL. In this paper we give an internal architecture and agent-based design of the FNL. We also show an experimental application using the FNL, the Dynamic Flow Control Application, which performs the user-oriented flow control, to discuss the characteristics and effectiveness of the proposed architecture.