Voice over IP (VoIP) stands for the use of the Internet as a communication channel. Voice information is transported in small packets over the Internet. In the early years of VoIP telephony, the data transfer rates were not yet sufficient to make every telephone call smoothly. With the DSL or fiber optic connections commonly used today, however, problem-free telephone calls are possible. Because the telecom providers want to implement their offer nationwide by 2022, VoIP telephony is becoming the standard. A VoIP telephone system is either locally installed hardware or software, but can also be operated as a virtual telephone system via the cloud. In addition to the usual range of functions of a telephone system, VoIP systems primarily offer integration into business software applications.