A Study of Improving Traffic Distribution Mechanism in Software-Defined Networking

Abstract

Recently, computer networks become one of the main components of the business processes in most organizations in the world. The size and complexity of network systems also continue to rapidly grow every year. When the networks become larger, many traffic flows are likely to propagate in the network at the same time. This event can lead to multiple performance problems, such as congestion, and slow response time. Traffic distribution mechanism is one of the main solutions for solving congestion problem. It aims to reduce the probability of congestion by splitting the traffic load into multiple paths. Furthermore, applying traffic distribution technique with Software-Defined Networking (SDN) is a promising solution that can effectively support both large-scale network implementation and also does not add high level of complexity to the network system. In this paper, the traffic distribution mechanism based on modified OpenFlow is proposed. The proposed method aims to decrease response time that a SDN switch must wait for the control message back from the SDN controller. It can be achieved by allowing the SDN controller to add the new flow entries for distributing the traffic load before the packet arrives at the SDN switch. The simulation experiments are conducted in Mininet to compare the performance between the proposed traffic distribution mechanism (TD_m) and the traffic distribution mechanism based on OpenFlow (TD_o). The results from the experiments show that TD_m can provide much better performance in term of End-to-End delay (E2E delay) and Packet delivery ratio (PDR) than TD_o in most of the experiment scenarios. However, both traffic distribution mechanisms (TD_o and TD_m) cannot provide good performance in term of E2E delay and PDR when the data transmission rate equals or higher than 500 Mbps. As a result, Time-Sleep mechanism is proposed to implement in SDN controller. The results from the simulation experiments show that Time-Sleep mechanism can notably improve the overall performance of both TD_o and TD_m even when the data transmission rate is high.