A Brief History of UC&C, Part One: VoIP and the Softswitch

For all of our readers who have read this newsletter faithfully over the last decade, we hope you can enjoy the next few editions as a trip down memory lane. And for those who are telecom neophytes, we hope you will enjoy learning a bit about the evolutionary factors we'll highlight.

One of the great things about a summer vacation is that you can take some time off to think about the past and about the future, so part of "how we spent our summer vacation" was thinking about the big trends that got us to unified communications and collaboration. So for all of our readers who have read this newsletter faithfully over the last decade, we hope you can enjoy the next few editions as a trip down memory lane. And for those who are telecom neophytes, we hope you will enjoy learning a bit about the evolutionary factors we'll highlight.

When we first started this newsletter back at the turn of the century, we titled this newsletter "Convergence" and initially promised to cover a then up-and-coming trend to put voice and data on the same network. We predicted subtopics of converged access, core, signaling and applications, although we weren't entirely sure what "converged applications" meant when we outlined out expected topics.

IN THE NEWS: Moves afoot in US, elsewhere to end PSTN copper lifeline

We started out covering voice over frame relay and voice over ATM (Asynchronous Transfer Mode) as these were the emerging protocols of choice for wide area networking. Carriers were using both protocols to combine enterprise voice and traffic with virtual private networks, although how to get voice from the private network to the PSTN was left largely to the enterprise IT manager, typically using a gateway for calls that had to connect to the outside world.

Then a funny thing happened on the way to the Internet called "dial access." Internet Service Providers (ISPs) like AOL and Earthlink sold subscriptions that connected computers by modem to the Internet. As the World Wide Web became more popular, local phone companies were facing PSTN meltdown because users would call into ISP dial access ports leave the link connected for hours while they surfed the Web. To make matters worse, these calls were typically to local numbers paid for by Internet Service Providers, so as incoming-only calls, they generated precious little revenue and severely disrupted telco engineering models.

Faced with the need to offload the PSTN voice network of ISP dial access calls, phone companies and some smart infrastructure engineers found a way offload their ISP traffic from the remote access servers directly onto a data network. The solution evolved into using a Class 4 (tandem) "softswitch" to route ISP dial access traffic away from the expensive Class 5 voice switches and onto a data network that better suited for ISP traffic. The softswitch approach initially used H.323 as a gateway protocol to communicate between the various voice and data calls, and the process carriers began to use Voice over IP (VoIP) to control voice traffic between Class 5 local voice switches.

Next time: "A Brief History of UC&C, Part Two: Enter the IP PBX."

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