Flexible Multi-link Ethernet Binding System for PC Clusters with Asymmetric Topology

In current high-performance PC clusters, the performance and cost of interconnection network are essential issues. Very cost-effective Ethernets, such as Gigabit Ethernet, as well as high performance SANs, such as Infiniband and Myrinet, are still widely used. The authors have been developing a multi-link binding network system for Ethernet, called RI2N, for high-throughput and fault-tolerant interconnection with Gigabit Ethernet. It can be used both for internode communication in MPI programs and traditional UNIX network services such as NFS. In this paper, the authors propose an optimized version of RI2N, called RI2N+, that allows asymmetrical multi-link connection for fitting to various cost-effective system configurations. Such a configuration cannot be supported by Linux Channel Bonding, which is widely used in standard Linux distributions. RI2N+ automatically detects the asymmetric network configuration and controls the traffic distribution to multiple links. In the basic performance evaluation under a high traffic rate, it was confirmed that the throughput of the network with the proposed scheme is improved by approximately 30% compared with the original RI2N. RI2N+ also maintains high performance even in asymmetric configurations, that is up to 86% of the relative performance compared with the symmetric case.