Investigation of the impact of network load on voip transmission quality

leads to the emergence of new approaches to qualitative and efficient information transmission. The transmission of voice messages is one of the most common types of data being transmitted. In classical analogue systems, speech was transmitted by channel switching. But with the emergence of a packet switching approach, a new ideology for voice messaging has emerged. IP telephony, with which you can deploy telephone corporate networks, is among the most effective ones, in terms of utilizing the available bandwidth and adaptive quality settings. Today, there is a large number of protocols for building IP networks, or its segments, but it is not a simple task to choose the "right" protocol under specific network conditions. The purpose of the article is to investigate the effect of telecommunication network congestion on VoIP transmission quality, to choose the optimal protocol for specific transmission conditions, such as preset quality parameters (QoS) and transmission speed. The article discusses the problem of determining the admissible level of telecommunication network congestion for the optimal operation of VoIP communication. A model of a telecommunication network, in which there is a load of voice and videoconferencing, a comparison of characteristics of voice traffic for voice codecs, comparative analysis of characteristics at different load, is proposed. The optimum network connection type and usage criterion are determined. The article deals with the simulation of telecommunication network segment in order to model and analyze the characteristics of the most common codecs used in IP networks. MOS voice quality metrics have been also introduced for all network congestion scenarios considered. Based on the research, recommendations regarding the use of different codecs for different network congestion to provide the set parameters of MOS factor have been made