IP trunking is large-scale, corporate, industrial or institutional use of VoIP. An entire organization hooks into the data world at large via one connection; that connection is then split among all the parties' phones and computers. While VoIP is used in millions of homes, IP trunking is almost exclusively used by businesses because they're the ones that have a need for multiple telephone lines and many telephony services (call waiting, voice mail systems, call forwarding, etc.), which are also carried via certain IP trunking services.
At its core, IP trunking and VoIP is voice on data lines. That means that voices travel over the Internet as bits of data, not "voices" or electrical impulses as they do on a traditional, land-based telephone line.
In addition to large data capacity methods like DSL and cable Internet, one of the ways IP trunking can handle multiple phone calls -- as well as Internet data usage coming from multiple places on a forked communications network in one building -- is via cloud computing. This means that the power of multiple computers all comes together to create a virtual, ad hoc "supercomputer" that, by creating a vast capacity to do so, handles the needs of the network, whatever those needs may be at any given moment. This extends to the IP trunking service provider. Its "cloud" of computers and networks powers your call. So the IP trunking consumer doesn't have to necessarily have a superfast computer or even a large computing network to make sure its calls and its data go through. Cloud computing replaces traditional telephony's line-to-line switching methods.
So now you know what IP trunking is and how it's possible to send a phone call out into the ether of the Internet. Read on to find out exactly how your voice turns into a "data packet," and how it's sent through a series of tubes to its destination. And also get an answer to this question: How do the same data networks can send your e-mails at the same time in the same place?