GRIN: Utilizing the Empty Half of Full Bisection Networks

Various full bisection designs have been proposed for datacenter networks. They are provisioned for the worst case in which every server wishes to send flat out and there is no congestion anywhere in the network. However, these topologies are prone to considerable under-utilization in the average case encountered in practice. To utilize spare bandwidth we propose GRIN, a simple, cheap and easily deployable solution that simply wires up any free ports datacenter servers may have. GRIN allows each server to use up to a maximum amount of bandwidth dependent on its available network ports and the number of idle uplinks in the same rack. This design can be used to augment almost any existing datacenter network, with little initial effort and no additional maintenance costs.