IP Telephony Primer
IP Telephony and VoIP are often used interchangeably as terms to describe a new way of handling telephone (voice) calls. At the simplest level, they describe how calls are transported on a LAN or WAN...using Internet Protocol. There can be great cost savings associated with this level, such as elimination of extra (and expensive) dedicated lines.
The most exciting part of IP Telephony, though, is all the new capability it provides—capability never before available. When data and voice are supported together on what is sometimes referred to as a converged network, all kinds of new possibilities open up. For example, mobile workers can retrieve their email, and CRM and Accounting/ERP systems can be integrated into the overall system.