Modern Problems of Mathematical Teletraffic Theory

We discuss the fundamental change - a paradigm shift in telecommunications, which in importance surpasses changes caused by the transition from the telegraph to the telephone, and consists in the transition from circuit switching to packet switching with IP-based technologies. The shift involves a change in fundamental and applied research. The presentation focuses on new directions for the development of the teletraffic theory, including the model of a multiservice network link with three types of traffic - unicast, multicast, and elastic. We formulate the problem for further research: 1. Development of methods for the analysis of QoS in P2P file sharing and streaming networks. 2. Analysis of the SIP (Session Initiation Protocol) models, including the task of developing mechanisms to monitor congestion in a SIP-server network. 2. Problems of cross-layer interface optimization for OFDM (Orthogonal Frequency Division Multiplexing) wireless networks.