What Are SIP Trunks?

“SIP trunks” are all the rage in the telecommunication industry.  What are SIP trunks?  No, these aren’t the shorts you wear while enjoying a cold beverage on the beach. Then what is a SIP trunk and when would I use this type of service?  I’m glad you asked.  First the jargon, then onto the plain English.

According to Wikipedia:

SIP trunking is a Voice over Internet Protocol (VoIP) and streaming media service based on the Session Initiation Protocol (SIP) by which Internet telephony service providers (ITSPs) deliver telephone services and unified communications to customers equipped with SIP-based private branch exchange (IP-PBX) and Unified Communications facilities.

Wow.  I’m in the telecommunications industry and that was even painful for me to read.  Let’s simplify this a little.  “Traditional” voice calls take place over the public telephone network – all of the copper wires that run in the air or underground, physically connecting telecom facilities.  There’s a neat little acronym (telecom is full of them) that goes along with that network too, but it’s irrelevant.  A SIP trunk simply takes that voice traffic and sends it over an IP network – either privately or across the internet.  This is results in a more efficient end to end solution.  Let’s see how…

Imagine you’ve just had a shiny new telephone system installed.  All the latest bells and whistles. Does it make sense to plug the same old phone lines into your new high performance system?  No way!  Today’s phone systems are IP based.  SIP trunks are IP based.  See where I’m headed?  SIP trunks play much nicer with newer IP-based telephone systems. It’s that simple.