A Framework to Assess Video Quality for Unified Telephony Communications in Enterprise Networks

Nowadays there are many audio-visual solutions involving person to person, multi-party telephony and web conferencing, collectively termed Voice/Video over IP (VVoIP). End users expect the quality of VVoIP to be either better than or at least equivalent to traditional telephony. Thus, it is very important for Enterprises to analyze the performance of their systems onto the network with respect to existing technology. Being a totally IP based service, VVoIP is much more susceptible to network uctuations and end-user application deployment. As an important requirement of end-user quality assurance, this work describes a novel testing framework for assessing and analyzing the call quality of unified telephony in enterprise networks in terms of Quality of Experience (QoE) as perceived by the end user. This framework includes analysis of the system performance under varied network conditions by emulation of network impairments. This framework is suitable for network planning as it formulates the relationship between network and application parameters and objective QoE scores. Packet loss pattern is another issue which plays an important part in video QoE assessment. Video-over-IP packets encapsulate encoded image frames of different type, functionality and size viz. I, P and B frames. Thus, one IP packet dropped could result in losing single or multiple frames having different level of importance and could impact the overall QoE in different ways depending on the particular frame types that were lost. A critical situation for video QoE is when important packets are lost which can deform not only a single frame but consecutive frames as well, reducing QoE from an expected level in the given network conditions and codec implementation. This work additionally presents a study on the impact of loss of specific types of frames on overall video QoE.