Software defined networks are a new Internet architecture paradigm that allows co-existence of heterogeneous network architectures.They optimize network management (maintenance, operability, and effective content delivery) by provisioning a centralized network intelligence. Virtual network embedding (VNE) algorithms improve scalability and utilization of physical resources in data center networks (DCNs). In this paper, we implement various DCN topologies and evaluate performance of VNE algorithms using the VNE-Sim simulator. We compare performance by implementing both server-centric and switch-centric DCN topologies.