Flexible Inter- and Intra-Switching Plane Resource Allocation in Data Center Networks

Technologies such as intelligent reflective surface (IRS)-assisted free-space optics (FSO) systems, are capable of providing connectivity with varied bandwidth through flexibly allocating resources on a planer panel. This flexibility provides new opportunities in handling inter-rack traffic that is often unevenly distributed in space and time. In this paper, we explore a new type of resource allocation scheme by taking full advantage of this flexibility. The key ideas include: (1) dynamically divide the resource on the planar panel into two planes, such that the small and large flows can be handled separately; (2) in the plane serving small flows, use multi-hop routing with variable bandwidth connections to handle skewed traffic between source-destination pairs; (3) in the plane serving large flows, use direct links with variable bandwidth to schedule unevenly distributed demand. In essence, through flexible resource allocation in and between the two planes, this scheme is able to make more efficient use of resources. We theoretically analyze the capacities of the proposed scheme, where the effectiveness conditions and performance bounds for dynamic resource adaptation are derived and the traffic scheduling with flexible bandwidth in two planes is proved to be able to achieve constant factor approximation to the ideally optimal performance. We then propose a set of lightweight algorithms with performance guarantees in each of two planes, collectively calledFlexAlloc, to realize the flexibility and adaptivity of the proposed scheme, and discuss an example of this scheme in the context of IRS-assisted FSO systems. Our simulation results show thatFlexAllocexhibits significant superiority over existing schemes for unevenly distributed traffic at low computational complexity, and can reduce the average flow completion time by 56-81%.