RDMA over Ethernet — A preliminary study

Though convergence has been a buzzword in the networking industry for sometime now, no vendor has successfully brought out a solution which combines the ubiquitous nature of Ethernet with the low latency and high performance capabilities that InfiniBand offers. Most of the overlay protocols introduced in the past have had to bear with some form of performance trade off or overhead. Recent advances in InfiniBand interconnect technology has allowed vendors to come out with a new model for network convergence-RDMA over Ethernet (RDMAoE). In this model, the IB packets are encapsulated into Ethernet frames thereby allowing us to transmit them seamlessly over an Ethernet network. The job of translating InfiniBand addresses to Ethernet addresses and back is taken care of by the InfiniBand HCA. This model, allows end users access to large computational clusters through the use of ubiquitous Ethernet interconnect technology while retaining the high performance, low latency guarantees that InfiniBand provides. In this paper, we present a detailed evaluation and analysis of the new RDMAoE protocol as opposed to the earlier overlay protocols as well as native-IB and socket based implementations. Through these evaluations, we also look at whether RDMAoE brings us closer the eventual goal of network convergence. The experimental results obtained with verbs, MPI, application and data center level evaluations show that RDMAoE is capable of providing performance comparable to native-IB based applications on a standard 10 GigE network.