Date: 2007-08-10 12:05 Subject: What is VoIP? Security: Public Tags: dameon welch-abernathy, phoneboy, rtp, services, sip, voip, weblog

Asks Dameon (aka Phoneboy) on the VoIP Weblog.  Here's my take on it:

The revolution is that the telephony platform has become software-based rather than in hardware (as in the so-called digital telephony platforms that have been with use through the 80s and 90s).  The media streams are all RTP and can arrive via an Ethernet adapter.  The control streams are largely SIP, which again comes via your Internet adapter, and this means that a standard PC is all the hardware you need to terminate 100's or even 1000's of connections.

The fact that so many technologies have converged on SIP means that all the things Dameon talks about: video, im, presence, voice can all arrive in your software platform via the same mechanism, which in turn means that what you do with those streams becomes only a software problem, and not a hardware one.  This is an incredibly democratic and empowering change, and it means that services can be implemented by anyone connected to the internet, only by creating software.

There are of course many different ways to write such software: a friend of mine has created his own SIP stack; others use Java APIs (like JAIN); there are a myriad SIP/RTP SDKs of various kinds, and also many emerging pieces of click-to-call 'glue' that allow call control to be done direclty from web serevrs, using programming systems like Python, PHP, .NET etc.  Telcos themselves are looking at Java, SIP Servlets, and web services via Parlay-X.  

Whether inside the telco or out, the lingua franca is SIP, so perhaps we can look forward to a future of co-operation, where some services are provided by the telco, some via companies like Google, and the software platforms on either side can co-operate with each other via the APIs.  Telcos have found it difficult to innovate and produce the services that customers are interested in, but turning telco into a software platform means that anyone can innovate, it's just a question of people opening the door and saying "yes".