Experimental analysis of software network emulators in packet delay emulation

Network emulators are powerful tools that allow to test and characterize network equipment and protocols. The market offers several measurement solutions. The most widely adopted are software network emulators and among them surely free or open-source emulators are the most used especially in research contexts. Unfortunately, software network emulators are not distributed with technical support and certified performance information. Certified information, about the ability of these software to accurately reproduce the wanted network conditions, is very important to validate the results obtained during design activity and test campaigns that involve them. In this paper, an experimental analysis of the ability of two widely used network emulators to emulate several imposed network conditions in different test set-ups is carried out. In particular, we have focused the attention on analyzing the fidelity in the generation of both static and random packet delays under different operating conditions. Obtained results confirm that imposed conditions are not equally reproduced and particular attention has to be paid in specific situations, as very low static delay imposed conditions.

I. Introduction

Nowadays the design and management of computer networks are very important tasks, because of the many value-added services like telephony, TV, banking, financial services they bring to the users. Network devices, applications and protocols performance assessment is fundamental in order to assure that these services are correctly provided to the user warranting his or her expectations. To this aim, a widely used technique is network emulation. In particular, it is applied in many different contexts as: Quality of Experience (QoE) assessment in wireless Local Area Network (LAN) [1], realization of smart grid test-beds [2], performance evaluation of video streaming services [3].