The book "Protocols and systems of IP-telephony and video-conferencing: a training manual" by I. and . Astrovsky is an indispensable source of knowledge for anyone interested in modern communication technologies. In the conditions of rapid development of information technologies and constant updating of communication systems , This guide becomes relevant for both students, Information Technology Studies , as well as for practitioners, seeking to expand their knowledge in IP telephony and video conferencing. The book examines in detail the key aspects of working with communication protocols that underlie modern telephony and video communication systems. Astrovskiy masterfully explains how various protocols, such as SIP (Session Initiation Protocol), RTP (Real-time Transport Protocol) and others, providing the reader with not only theoretical knowledge, but also practical recommendations for their application. The author emphasizes the importance of choosing the right protocol for a specific task, which makes the book especially useful for system administrators and engineers working in the field of telecommunications. A world opens to the reader in which IP telephony and video conferencing become an integral part of business and everyday life. Astrovsky not only describes the technical details, but also touches on the integration of these technologies into existing systems, which makes his manual relevant for managers and managers seeking to optimize communication processes in their organizations. The book will be of interest to both beginners and experienced professionals who want to update their knowledge about the latest trends and innovations in the field of communication. The topics raised in the book cover a wide range of issues, from the basics of network architecture to the practical aspects of setting up and operating video conferencing systems. Astrovsky also pays attention to security issues, which is an important aspect in the face of growing cybersecurity threats. Readers will be able to learn about methods of data protection and ensuring confidentiality in the process of communication, which makes the book especially valuable for organizations working with sensitive information. The author's style is distinguished by clarity and accessibility, which makes it easy to assimilate even the most complex technical concepts. and . and . Astrovskiy is an experienced IT specialist, and his previous work has also earned recognition among professionals. The book “Protocols and systems of IP telephony and video conferencing” continues the traditions of its previous editions, offering readers high-quality and relevant content. This book will be an excellent addition to the library of any IT specialist, student or teacher interested in modern communication technologies. It will also be useful for those who are looking for information on such requests as “IP-telephony”, “video conferencing”, “communication protocols”, “communication technologies” and many others. If you want to be aware of the latest developments in the field of communication and learn how to effectively use these technologies in your work, then the manual and . Astrovskiy will become your reliable guide in this fascinating world .