Currently, Voice over Internet Protocol telephony system, also known as VoIP, is the latest technology that allows calls to be made over the Internet. The importance of this technology is based especially on how it works, its many features and advantages, including cost savings and portability, i.e., it is very low in price and can be used in different parts of the world, which today is practically a necessity. This VoIP service is growing rapidly thanks to the bandwidth it can reach; and, thanks to the quality of service it provides to the user. This research takes advantage of the TCP/IP model and open-source software platforms that allow the VoIP service to be integrated into an existing computer network or into a new network design. Likewise, the VoIP service provides features, advantages and disadvantages that can help optimize organizational communication. On the other hand, designing a new computer network for VoIP or using the installed telecommunications infrastructure allows organizations to decide which is the best method to follow, which type of network is more accessible, and which version of TCP/IP has the best performance. This allows organizations to reduce costs both in infrastructure and the implementation of these new services.