This paper proposes a novel architecture of data center networks, which adds wireless network cards to all servers and routers. Wireless communication enables the logically centralized control over the physically distributed states in the emerging software defined networks (SDN) paradigm, by sharing control information among servers and routers. This paper is the first to explore traffic redundancy elimination (TRE) mechanisms in large-scale data center networks (DCN). A large fraction of the traffic in DCN is redundant. TRE mechanisms increase network capacity by removing strings that have appeared in earlier packets and attaching them several hops downstream at routers where this string has been previously cached. Finding an optimal caching task assignment for TRE in DCN is proven to be NP-hard. The authors design an offline algorithm and show that its total cache utility exceeds half of a theoretically optimal bound. They further describe the corresponding online implementation that is supported by physical proximity of servers and routers. They also address the issues of online cache replacement and consistency of information in servers and routers. The proposed framework achieves a superior performance in comparison to other mechanisms through extensive simulations, and shows the robustness of the SDN implementations in DCNs enhanced by wireless communication.