A SIP trunk is the digital version of an analog phone line. Learn how you can upgrade to a unified digital phone system for ...

In our last VoIP installment, we looked at the main reasons why SIP has become a widely adopted protocol, but we left details of the protocol’s inner workings fairly vague. This article will drill ...

The iptel.org 180+ page SIP tutorial is outstanding. Another overview that is a bit more market-oriented and nearly as long. White paper on the SIP value proposition over telephony, SIP and the new ...

Even many IT professionals haven't heard of the Session Initiation Protocol (SIP), so it's almost certain your users haven't. However, unless you're using an entirely proprietary Voice-over-IP (VoIP) ...

Barrett Lyon has created a don't miss resource that shows you how to configure P2P SIP URI (Uniform Resource Identifier) dialing on your Asterisk-based PBX. "There are thousands of people that operate ...

In Part 1 of our SIP primer, I covered the SIP foundation layers starting from the message structure and ending with the SIP transactions. We saw how phone registrations and proxies could work using ...

What's VoIP's Big Security Problem? SIP Session Initiation Protocol (SIP) is a must for voice over IP (VoIP) communication. But by itself, SIP is insecure and easily hacked. Here's what you need to ...