Calls must be carried among diverse networks. This is a concern not only from an access perspective, but also for overflow purposes. Voice over data systems must be able to grow cost-efficiently. New users will demand new connections. When channels are shared, as with packetized voice and data, it is critical that voice conversations be secure, so that others cannot overhear what is said.
Enhanced voice features.
Revenues are rich for enhanced voice services, such as voice mail and custom calling features. To fully compete, the new voice over data offerings will have to provide the same level of enhanced services as consumers are accustomed to today.