IP telephony (Internet Protocol telephony) is a term used to describe technologies that use a variety of protocols to exchange voice, fax, and other forms of information, traditionally carried over the Public Switched Telephone Network (PSTN). The call travels in the form of packets, over a Local Area Network (LAN), or the Internet, avoiding PSTN tolls.
Starting in the mid, to late 1990s, the Internet and the TCP/IP protocol began to drive the telephone and communications industry to change. The Internet Protocol became the transport for almost all data communications. Today, all communication carriers are using an IP infrastructure for a part, or for all of its voice services. Most companies have already switched from PSTN to using VoIP (Voice over IP) for their internal voice communications or have plans to implement it as part of their Unified Communications solution.
There are various protocols that can be used to implement IP telephony including:
- Session Initiation Protocol (SIP)
- Real-time Transport Protocol (RTP)
- Real-Time Transport Control Protocol (RTCP)
- Secure Real-time Transport Protocol (SRTP)
- Session Description Protocol (SDP)
IP Telephony in Business
The benefits of IP telephony in corporate environments are numerous, but are mostly narrowed down to cost considerations related to infrastructure and monthly telco bills. Modern VoIP PBX solutions, like 3CX, allow for companies to run the system on existing, non-proprietary hardware as well as low-cost machines such as Mini-PCs. Traditional phone systems and proprietary VoIP solutions require extensive implementation of closed architectures, which can cost hundreds of thousands of dollars and are much more difficult to manage, configure and maintain. Open standards IP telephony systems are also much easier and more cost-effective to scale.
The use of VoIP and SIP trunk service providers means that phone bills are greatly reduced. This is because companies can easily connect branches in other cities and countries, making calls within the company free. Long-distance charges are slashed and overall call rates are much cheaper.
Business telephone systems are now able to offer much more to companies that standard telephone calls. IP telephony has ushered in the development of unified communications solutions which can provide a complete communications package all in one, to be ran over a single network and on one platform. This means that businesses can easily manage calls, use video conferencing, collaborate, chat and more through a single service. These solutions have also allowed users to make VoIP telephone calls through their smartphones and computers, either with the use of apps or web clients.