SIP Trunking and Modern Telecommunnications

Voice communications is changing rapidly, and in your research you’ve probably run across something called SIP trunking. What is SIP trunking and why do you care?

SIP trunking is tied closely to the private branch exchange (PBX) systems that have run office phone networks for years, and it is where a lot of the magic of voice-over-IP (VoIP) takes place.

PBX systems have long been in use as the way that businesses move from discrete, individual business phone lines to an internal telephone network that connects workers through voicemail, telephone extensions, and interactive voice response systems. With a PBX, a call comes in, and it then can be transferred throughout the PBX calling network to other phones in the system, or to an interactive voice response system, such as a company directory.

SIP trunking basically takes the power of a PBX system and extends it outside of corporate walls, connecting calls from anywhere in the world as if they were connected via a PBX system. Where a traditional PBX system routed a landline call through a company network, SIP trunking can route a landline call onto the global Internet and through various localized networks until it reaches its eventual destination.

A good way to think of what SIP trunking does is to think of it as a calling cloud that sits on top of a local voice protocol to release voice into the IP network. When the call is released, it then is routed to the right place.

Some of the advanced functionality that SIP delivers include call seeking, shared web browsing and virtual numbers. For instance, SIP trunking can allow a call to arrive at a desk phone, then a cell phone if the desk phone doesn’t answer, then a third phone if necessary, seeking until the call finds someone to answer it.

SIP trunking also allows for shared web browsing, where files can be sent around a network for collaboration no matter where the collaborators are located.

A third and often used advantage of SIP trunking is the ability to set up virtual numbers. These numbers, through the magic of SIP trunking, can be overlaid on top of other numbers. So a virtual number might let a business have a “local” number for its customers that actually resolves to a phone in another state—or several phones, as the seeking example above indicates.

Voice communications is changing, and SIP trunking is playing an important part in its evolution.

Clicky