Energy-efficient Deployment of Fat-Tree Hybrid Data Center Networks

Abstract

Augmenting 60GHz wireless device to the Top-of- Rack (ToR) switch to build hybrid Data Center Network (hybrid DCN) is proven to be effective in alleviating traffic congestion in DCN. However, wireless transmissions at very high frequency suffer from limitations of short transmission range, blockage, and interference. In the Fat-Tree hybrid DCN, ToRs are classified into two types: ToRs within the same pod (intra-pod ToR) and ToRs between different pods (inter-pod ToR). To establish wireless links between inter-pod ToR switches is more efficient than that within the intra-pod, due to the reduction of switches and the cost resulting from multihop transmissions. In this paper, we propose an energy-efficient offline deployment scheme to construct the Fat-Tree hybrid DCN by jointly considering the wired and wireless links. The proposed sheme can maximize the number of wireless links between inter-pod ToRs and make the wireless links distribute evenly among different pods. The numerical results show that the proposed scheme can potentially exploit the wireless links between different pods to enhance the network energy efficiency by reducing the average path length and the use of switches in the hybrid DCNs.