What Is SIP Trunking?


The Many Definitions of SIP Trunking

by Adam Uzelac – Global Crossing

About 490,000 results (in 0.20 seconds, for what it’s worth) – that’s the number of results from “Guru Google” when asked to return information from the search, “What is SIP Trunking?” As you might guess, there are many different definitions of SIP (Session Initiation Protocol) Trunking freely available on the Internet. Regardless of the definition that you subscribe to, enterprise cost-savings MUST be at the heart of the definition. SIP Trunking is a solution in VoIP communications by allowing a concurrent call(s) to pass over a SIP Service Provider’s IP backbone using SIP technology.

Wikipedia gives another definition to what SIP Trunking is:

The Wikipedia definition states: “In telecommunications networks SIP Trunking is a VoIP solution based on SIP protocol. This Solution allows ITSP (Internet Telephony Service Providers) to give Voice Services and unified communication via IP access to business customers (companies) equipped with a private infrastructure generally based on IP-PBX (Private Branch eXchange technology in IP)”. Source

I was asked to pontificate with a few colleagues to explain Global Crossing’s definition of SIP Trunking. In this first part of the “SIP Trunking Series with Global Crossing”, I explain what SIP Trunking is and the evolutionary path that got us to SIP Trunking.


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