What the Heck is a SIP Trunk?

No...this is not going to be SIP Trunking 101. I think most of you out there know what a SIP Trunk is. However, have you considered that most of the people we are selling them to have no clue. When I first heard the term SIP Trunk I was rather embarrassed to realize I had no understanding of what was being discussed. I knew VoIP, TDM and what a trunk was, but a SIP Trunk was alien to me. Therefore, I did what most of us twenty plus year veterans in telecom would do. I looked it up in my copy of Newton's Telecom Dictionary 17^th Edition. I did not find it. I wasn't too surprised since it is the 17^th Edition and Newton is now up to 24^th. No problem though, I called a telecom engineer I knew and asked him. I was certain he would know because he built an open source IP PBX. For various reasons, I now have the PC platform and use it as a backup server for my home PCs. Much to my surprise, he was of no help either. He knew a lot about VoIP, had an understanding of SIP but the phrase SIP Trunk was as foreign to him as to me.

I then turned to the web. I devoured various articles until I saw a definition that worked for my TDM based mind. It wasn't so much about the protocol or the IP technology; it was about the connection between two network elements, a PBX and a service provider. Okay, I understood trunks, I understood SIP, and I now understood why we had SIP Trunks.

So why are we discussing this today. Last night I was asked, "What is a concurrent call session?" As I thought about defining a CCS, I thought again about how much education we still need to perform. (If you don't know what a CCS is, look it up. Although not even a recent edition of Newton's will help. As of the 23^rd Edition, SIP Trunking, SIP Trunks and Concurrent Call Session had not made the cut).

As we work with our VARs, agents, distributors and dealers, keep in mind that they are encountering people that simply put, "Have no clue." Moreover, most of our technical sources of information are of no help.

The IP community needs to continue to develop white papers, case studies, and training that enables our channels to extend this knowledge to the SMBs and enterprise IT and Telecom managers that need it. The history of IP Communications has not been written. We know when it began but its evolution, acceptance and general use remain to be determined. There are yet game changing events and significant product offerings awaiting us. Unified communications, presence, etc. are just the beginning.

It's not over until the SIP Trunk sings.