Energy-Efficient Flow Scheduling and Routing with Hard Deadlines in Data Center Networks

TL;DR

This paper introduces a novel energy-efficient flow scheduling and routing approach in data center networks that guarantees performance deadlines while minimizing power consumption using speed scaling and power-down strategies.

Contribution

It presents a polynomial-time optimal algorithm for flow scheduling with pre-given routes and an approximation algorithm for joint scheduling and routing, addressing energy efficiency with deadlines.

Findings

Optimal polynomial-time algorithm for flow scheduling with fixed routes

NP-hardness of joint flow scheduling and routing problem

Approximation algorithm with provable performance ratio

Abstract

The power consumption of enormous network devices in data centers has emerged as a big concern to data center operators. Despite many traffic-engineering-based solutions, very little attention has been paid on performance-guaranteed energy saving schemes. In this paper, we propose a novel energy-saving model for data center networks by scheduling and routing "deadline-constrained flows" where the transmission of every flow has to be accomplished before a rigorous deadline, being the most critical requirement in production data center networks. Based on speed scaling and power-down energy saving strategies for network devices, we aim to explore the most energy efficient way of scheduling and routing flows on the network, as well as determining the transmission speed for every flow. We consider two general versions of the problem. For the version of only flow scheduling where routes of flows are pre-given, we show that it can be solved polynomially and we develop an optimal combinatorial algorithm for it. For the version of joint flow scheduling and routing, we prove that it is strongly NP-hard and cannot have a Fully Polynomial-Time Approximation Scheme (FPTAS) unless P=NP. Based on a relaxation and randomized rounding technique, we provide an efficient approximation algorithm which can guarantee a provable performance ratio with respect to a polynomial of the total number of flows.