Tahani Ismail AliAshraf Gaism AbdallaAmin Babiker A/Nabi2018-01-172018-01-172017-01-16http://hdl.handle.net/123456789/10345مؤتمرAbstract A simulation model is presented to analyze and evaluate the performance of VOIP over WAN with taking into account various voice encoding schemes. The network model was simulated using OPNET Modeler software. Different parameters that indicate the QoS like MOS, jitter and end toend delay were calculated and analyzed in WAN scenarios.Depending on this evaluation, Selection codecs G.729A consider the best choice for VoIP. 174Analysissimulation modelvoice encoding schemesWorking Paper