On the Parallel Reconfiguration of Virtual Networks in Hybrid Optical/Electrical Datacenter Networks

Recently, hybrid optical/electrical datacenter networks (HOE-DCNs) have been considered as a promising DCN architecture, because they merge the merits of electrical packet switching (EPS) and optical circuit switching (OCS). This paper considers the reconfiguration of virtual networks (VNTs) in an HOE-DCN to address the dynamic nature of emerging network services. Specifically, we study the problem that given the original and new virtual network embedding (VNE) schemes of several VNTs, how to schedule parallel virtual machine (VM) migrations in batches to realize the VNT reconfiguration within the shortest time. We design two algorithms to reconfigure the inter-rack network in an HOE-DCN in steps, schedule VMs to migrate accordingly, and allocate bandwidth to the VM migrations. The first algorithm uses the one-shot approach, where all the VM migrations are conducted in parallel within the shortest possible time. We formulate a linear programming (LP) to solve the bandwidth allocations in it exactly. Next, to relieve the bandwidth competition introduced by the one-shot approach, we propose the second algorithm by leveraging the multi-shot approach, i.e., invoking multiple batches of parallel VM migrations such that the reconfiguration time can be further reduced. Extensive simulations verify the effectiveness of our proposals.