This paper proposes a scalable network emulator architecture to support IP optical network management. The network emulator uses the same router interfaces to communicate with the IP optical TE server as the actual IP optical network, and behaves as an actual IP optical network between the interfaces. The network emulator mainly consists of databases and three modules: interface module, resource simulator module, and traffic generator module. To make the network emulator scalable in terms of network size, we employ TCP/IP socket communications between the modules. The proposed network emulator has the benefit that its implementation is not strongly dependent on hardware limitations. We develop a prototype of the network emulator based on the proposed architecture. A virtual machine (VM) technology is employed to reduce the hardware amounts required for this implementation. Our design and experiments show that the proposed architecture is effective. Thanks to the scalability and flexibility of the proposed architecture, it is expected that network-size can be easily scaled up.