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 ...

I was a speaker this week at Channel Partners show, on the topic of Microsoft (News - Alert) OCS-Office Communications Server and SIP. This was followed by a session on SIP trunking. Surprisingly or ...

I've been clicking around the Flash-enabled VoIP eLearning Tutorial. Authoritative, vividly illustrated, and totally cool. You click, and you see illustrated guides to how VoIP works, how to configure ...

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 ...