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.