Scheduling Opportunistic Links in Two-Tiered Reconfigurable Datacenters

TL;DR

This paper introduces a stable-matching online scheduling algorithm for reconfigurable datacenter networks, reducing flow completion times by efficiently managing opportunistic optical links in a two-tier topology.

Contribution

It presents a novel online scheduling algorithm with provable competitive guarantees for reconfigurable datacenter topologies, extending classic switch scheduling to more complex, hybrid networks.

Findings

Achieves a 2·(2/ε+1)-competitive ratio against optimal offline algorithms.

Works with variable link delays and hybrid fixed-reconfigurable topologies.

Uses LP relaxation and dual fitting for analysis.

Abstract

Reconfigurable optical topologies are emerging as a promising technology to improve the efficiency of datacenter networks. This paper considers the problem of scheduling opportunistic links in such reconfigurable datacenters. We study the online setting and aim to minimize flow completion times. The problem is a two-tier generalization of classic switch scheduling problems. We present a stable-matching algorithm which is $2\cdot (2/\varepsilon+1)$-competitive against an optimal offline algorithm, in a resource augmentation model: the online algorithm runs $2+\varepsilon$ times faster. Our algorithm and result are fairly general and allow for different link delays and also apply to hybrid topologies which combine fixed and reconfigurable links. Our analysis is based on LP relaxation and dual fitting.