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 ...

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 ...

The term Voice over IP (VoIP) does not refer to a single service but encompasses an entire collection of services that can fill the phone service needs of many different residential and business ...

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 ...