The demand for high network capacity has been rapidly increasing, that is why network infrastructures with multi-Tbps connection speeds are being carefully designed. However, the transport over the network with high bandwidth and delay such as inter-DC WANs, cannot fully utilize the bandwidth because of the inevitable packet loss. We theoretically analyze the problem and found that the root cause is the flow control bottleneck caused by the out-of-order data blocked in the receive buffer because of TCP ordering guarantee. We further found that a lot of applications over inter-DC WANs such as server mirrors and data backups are nonreal-time, which means they don’t quite care about the data arriving sequence. Thus, we design and implement Freeway to improve the bandwidth of these non-real-time applications over inter-DC WANs. Freeway is a user-space bulk-data network transfer framework, including a server consisting of a user-level transport layer together with a non-real-time application built on an order-less socket API, and an optional user-space bulk-transfer client. The order-less socket API can directly deliver out-of-order data to the non-real-time application, so that the transport layer can safely extend the receive window to avoid the flow control bottleneck. The Freeway server and client are both full compatible with commodity Linux TCP stack, so they can be deployed only at the server side or the client side, but get best performance when they are both enabled. We evaluate the Freeway’s performance comparing with Linux TCP stack, and show that Freeway achieves 100% more bandwidth utilization than Linux TCP stack, and significantly reduces memory cost.