If All-IP Is Where We’re Going, Where Are We Right Now?
Over the course of the summer, while co-teaching a class about how cable technology works, one question came up, every time: “If all-IP (Internet Protocol) is where we’re going, where are we right now?”
As television milestones go, all-IP is arguably as significant as the shift to color from black-and-white TVs, in the early ‘50s, and when satellite transmissions began, in 1975, and when analog ceded to digital, in the mid-‘90s.
Each phase sparked major growth. Color TVs bumped sales of TVs in general. Satellite distribution opened the door to national scale, which begat the hundreds of TV channels available to us now. Digital made room for high-definition, then broadband services. Broadband is innately IP, so making room for more of it is what this transition is all about.
Which brings us back to the question. If all-IP is where we’re going, where are we now? If you asked an engineering colleague this question, you’d likely get one of two answers: “QAM,” or “MPEG transport.”
The first (QAM) is technically wrong, as direct comparisons go, but nonetheless right because we’ve all used it for so long. It just stuck.
The other (MPEG transport) is confusing because it’s also the term people use to describe digital video compression.
Let’s look at the “P” part of “IP.” Protocol. Protocols are sets of rules that define how data is transmitted and received, so that two or more machines can talk to each other.
What size are the packets? How are errors handled – with forward error correction (FEC), or by re-sending? What’s the data to do when a piece of the transmission path goes kaflooey?
In that case, then, the correct answer for where we’re coming from, as we head to all IP, is “MPEG transport.” MPEG stands for Moving Pictures Experts Group, and is the standards body that gave us MPEG-2 and MPEG-4 compression.
Part of the MPEG compression standard defines transit. Hence “MPEG transport.” It’s the protocol underlying every fielded digital set-top, cable modem, gateway and voice adaptor out there. And lots of consumer devices.
Still, people often refer to where we are now as “QAM.” Quadrature Amplitude Modulation. Modulation, in general, defines how signals get imprinted onto a communications carrier, to get from here to there. Protocols define how the end points talk to each other. So, even when things are “all-IP,” they’ll still (in cable) move using QAM.
It was at the 2003 Cable Show when Bill Gates and Brian Roberts got to talking about whether and when the cable industry would go from all-digital, to all-IP. At the time, the conversation prompted headlines like “What The Heck Was Bill Gates Talking About?”
And here we are, a decade later. All-IP is still a matter of “when,” not “if.” It’s still the destination. And it’s still going to take a really long time to get there.
This column originally appeared in the Platforms section of Multichannel News.