  In this paper we propose Virtuoso, a purely software-based multi-path RDMA
solution for data center networks (DCNs) to effectively utilize the rich
multi-path topology for load balancing and reliability. As a "middleware"
library operating at the user space, Virtuoso employs three innovative
mechanisms to achieve its goal. In contrast to existing hardware-based MP-RDMA
solution, Virtuoso can be readily deployed in DCNs with existing RDMA NICs. It
also decouples path selection and load balancing mechanisms from hardware
features, allowing DCN operators and applications to make flexible decisions by
employing the best mechanisms (as "plug-in" software library modules) as
needed. Our experiments show that Virtuoso is capable of fully utilizing
multiple paths with negligible CPU overheads
