Data center networks (DCNs) usually have a regular topology providing high bandwidth and low latency with multipaths. In a data-intensive application on DCNs, it is important to be able to use all the available bandwidth. However, this is not easy to achieve because of the locality of congestion information. In this paper, we propose a reactive reroute strategy to incorporate with IEEE 802.1Qau standards on Ethernet-based DCNs so that we can exploit the multipath property of a network to reduce congestion, and hence improve performance. We show by simulation that the throughput is significantly higher and the number of out-of-order packets induced by rerouting is limited.