Vulnerabilities of the classical
Definitely, the use of IP-telephony is more profitable than traditional. There is a wide additional functionality, and the cheapness of calls, and the management of remote offices, and the high quality of communication, and a single information field within the team, and a reporting system, and much more.
However, the “cloudy” location of classic VoIP telephony can create dangers that did not exist before its invention: data interception, DDoS attacks, unauthorized access to the corporate network. Despite the fact that 99% of companies do not encounter such problems in practice, you need to be aware of them.