Long Term Evolution, a mobile 4th generation network, is the first mobile network exclusively utilizing packet (TCP/IP) switching. It represents a major leap forward in comparison to the networks of the previous generations where at least parts of them were circuit switched, leading to the unification of the LTE architecture, and in turn to reduced costs and expansion of available services. LTE architecture can be split to: · access (radio) segment - base station eNodeB · Evolved Packet Core - segment comprised of a few network entities, all working to ensure the propagation of connection and linkage with the rest of the network · control segment - with authentication and authorization being the main tasks, the segment in question will make sure to dynamically allocate network resources; main role is designated to PCRF, a network element establishing proper policy and charging rules for each user. Precisely due to the evolution of packet switching, an idea arose of forming a technology and a standard that will bring increase in quality to user voice communication - VoLTE, for which the characteristic flows are shown.