The reason for the prevalence of VoIP is that it gives significant benefits compared to legacy phone systems. The key benefits are as follows:
Cost savings. The most attractive feature of VoIP is its cost-saving potential. When we move away from public switched telephone networks, long-distance phone calls become inexpensive. Instead of being processed across conventional commercial telecommunications line configurations, voice traffic travels on the Internet or over private data network lines.
For the enterprise, VoIP reduces cost for equipment, lines, manpower, and maintenance. All of an organization's voice and data traffic is integrated into one physical network, bypassing the need for separate PBX tie lines. Although there is a significant initial setup cost, significant net savings can result from managing only one network and not needing to sustain a legacy telephony system in an increasingly digital and data-centered world. Also, the network administrator's burden may be lessened as they can now focus on a single network. There is no longer a need for several teams to manage a data network and another to manage a voice network. For consumers, VoIP reduces the charge of subscription or usage, especially for long distance and international calls.
Rich media service. The legacy phone system mainly provides voice and fax service even though limited video service is possible. However, the demand of users is much higher than that, as shown in today's rich media communications through the Internet. People check out friends' presence (such as online, offline, busy), send instant messages, make voice or video calls, transfer images, and so on. VoIP technology makes rich media service possible, integrating with other protocols and applications. Rich media service not only provides multiple options of media to users, but also creates new markets in the communications industry, such as VoIP service in mobile phones.
Phone portability. The legacy phone system assigns a phone number with a dedicated line, so you generally cannot move your home phone to another place if you want to use the same phone number. It is a common hassle to call the phone company and ask for a phone number update when moving to a new house. However, VoIP provides number mobility: The phone device can use the same number virtually everywhere as long as it has proper IP connectivity. Many businesspeople today bring their IP phones or softphones when traveling, and use the same numbers everywhere.