This story was contributed by a reader. To get your voice heard, contact Network World Editor in Chief John Dix at jdix@nww.com.

The cold-war between Microsoft and Cisco for the much coveted "unified communications" market has escalated to all out war, with Microsoft Chairman Bill Gates predicting "the death of the PBX."

Before we delve deeper I have to come clean. My day job is as senior network engineer for a Cisco VoIP partner. I have a vested interest in seeing the Cisco side of things dominate. But long ago I realized there is no use digging your head in the sand when something new comes along. Hence the hours I should have devoted to studying for my CCIE Voice lab exam have instead been spent attempting (mostly successfully) to understand, use and integrate the Microsoft IP telephony and VoIP solutions to the best possible advantage.

Depending on who you talk to, unified communications is described as telephone and video collaboration, or as a converged network for voice and data, or used as an all-encompassing term to describe all forms of call and multimedia/cross-media message-management functions. For now, I'll use it to refer to any IP telephony solution that can co-exist with data.

Unless you have been living in a cave, you have to have noticed the buzz surrounding unified communications. In fact Gartner identifies it as one of the "Top 10 Strategic Technologies for 2008". It is a competitive space currently filled by traditional PBX vendors (such as Avaya, Nortel, Alcatel, etc.) and some would say dominated by Cisco who long ago realized that IP telephony is more than just a way to help sell more POE switches.

Microsoft entered the market with much gusto with the release of Office Communication Server 2007 in October but, truth be told, the company has been dabbling in this space long before.

That Microsoft has experience with VoIP should come as no surprise. After all, the fundamentals of VoIP and IP telephony are simple: signaling protocols (such as the open standards SIP, H.323 and MGCP and the Cisco-proprietary SCCP) create and tear down calls between two like-protocol end-points, while the actual voice is encoded inside a codec (such as G.711, G.729) and is then transported over an RTP stream (RTP being a simple extension to UDP).