## 1 Introduction  
Building a network based on IP PBX Asterisk starts with analyzing and choosing a Linux distribution, as there are many and there are distributions that can meet the needs of each. The analysis of existing distributions shows that in any distribution the main principles remain unchanged. The IP PBX Asterisk software began as a telephony system for small businesses, but over the decade since its initial release, it has become a universal tool for creating communication applications for medium-sized businesses. Today, Asterisk is used not only in IP-PBX systems, but also in VoIP gateways, call center systems, conference bridges, voice mail servers, and all types of other real-time communication applications. Asterisk PBX has key advantages such as scalability, cost-effectiveness, customization, flexibility, etc. The Asterisk PBX software 16.16.1 can be easily scaled up or down to meet the changing needs of an organization [1]. The Asterisk PBX software is an open source solution, which means that it is free to download and use. This helps organizations save on the cost of expensive proprietary PBX systems [2]. In addition, the Asterisk PBX software is highly configurable, which means that organizations can modify and extend the functionality of the software to meet their specific needs [3, 4]. As noted in [5], the Asterisk PBX software can be integrated with a wide range of telephony hardware and software, allowing organizations to use existing equipment and infrastructure. Asterisk PBX also supports voice over IP (VoIP), which means that, while using existing equipment and infrastructure, organizations can also make and receive calls over the Internet, which can help reduce the cost of long distance calls [6; 7; 8]. The Asterisk PBX software should also be used to expand the range of additional features such as call routing, voice mail, conference calls and call recording [9; 10]. To ensure the security of the network built on the basis of Asterisk PBX, there is a wide range of security features, such as encryption, authentication, and authorization, which help protect against unauthorized access to the system and data [11; 12; 13]. For such setups, the Asterisk PBX software is highly available, which means that it can automatically fail over to a standby server in the event of a hardware failure or other problem, ensuring that services are always available [14; 15; 16; 17]. Asterisk is a flexible and versatile system that is one of the most commonly programmable PBXs deployed within corporations due to its open access technology and modular and flexible design. Given the capabilities of the IP PBX Asterisk, its main criterion for choosing an office IP PBX is the ability to scale and integrate into the company's existing computer network at minimal cost. The main component of the network infrastructure of the IP network is the telephone exchange. Asterisk allows a server to be used as a telephone exchange, which can be any computer with an operating system of the Linux family installed on it (including virtual machines). Small and home offices require a minimum of 512 MB of Random Access Memory (RAM) and a 1 GHz processor (up to 10 channels). A small business system with up to 25 channels requires 1 GB of RAM and a 3 GHz processor [18; 19]. This is below the capabilities of modern office personal computers, which are widely sold. The telecommunications industry is undergoing great changes, but is in no hurry to use them. Asterisk, on the other hand, is in a great hurry to not only embrace change, but actively embrace it. Asterisk significantly outperforms all PBX solutions on the market, as it has extensive programming capabilities that allow complex call processing algorithms to be implemented [20; 21]. Compliance with standards has become evident over the past few years: standards change so quickly that the only way to keep up with them is to be able to quickly respond to new directions emerging in technology.