A Brief History of UC&C, Part Three: UM, UC and SIP

Continuing our mini-series, today we will discuss unified messaging, unified communications and the importance of presence as contributors to the evolution of unified communications and collaboration.

Back about 10 years ago, unified messaging (UM) was all the rage. Or to be more precise, talking about unified messaging was all the rage. The concept behind UM was to make easy access to the burgeoning choice of messages that were beginning to bombard consumers and enterprise users. Most adult users in residential and business market segments were using mobile phones and wired phones with each having its own unique voice mail system. Voice mail messages, text messages, faxes and email contributed to information overload and users were growing uncomfortable with having so many interfaces to check for that all-important message. UM brought access to audio, text and (later) video messages from a phone or a PC -- providing equal messaging access using techniques like speech-to-text and text-to-speech.

A BRIEF HISTORY OF UC: Part One | Part Two | Part Three | Part Four | Part Five

While consumer market for unified messaging came and left, the market for unified messaging among enterprise users stayed, eventually evolving into unified communications (UC). UC added the dimension of real time communications to UM, solving a real business issue of letting users pick who can reach them, under what circumstances and using what media, whether desk phone, mobile device or a chat session on a PC. The key enabler for real time access to multiple media was "presence" and the standards-based protocol of choice to enable presence was SIP, or session initiation protocol.

SIP is an application layer protocol approved by the Internet Engineering Task Force (IETF) so it brings that advantage of being compatible with other IP protocols and applications that use IP like PC-based calendaring and email systems. SIP is designed to concurrently manage "sessions" between two or more devices, allowing, for example, simultaneous ringing on both mobile and wired devices, and monitoring both networks so when a call is received on one network, the other network no longer needs to carry the call . SIP was also approved as the underlying session control protocol by the 3GPP (a mobile phone systems standard body) to manage and monitor IP streaming media in mobile networks for IP Multimedia Subsystems (IMS) architectures.

We'll continue our summer series next time with a look at how video and telepresence became part of the collaboration equation. Read part 4 of this series.

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