This Recommendation describes a computational model for point-to-point interactive videophone applications over IP networks that is useful as a QoE/QoS planning tool for assessing the combined effects of variations in several video and speech parameters that affect the quality of experience (QoE). This model can be used by QoE/QoS planners to help ensure that users will be satisfied with end-to-end service quality. Actually they want to avoid under-engineering. Network, application and terminal quality parameters of high importance to QoE/QoS planners are incorporated into this model.