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What the Heck Gates Meant

Attendees at last week's National Show spent a fair amount of chat time chewing on an opening-session exchange between Microsoft Corp. chairman Bill Gates, and Comcast Corp. CEO Brian Roberts.

The overall attendee reaction: What on earth were they talking about?

For those who didn't attend, here's the set-up: Roberts asked Gates what he meant earlier this year, when he told a group of muckety-muck cable executives at the Consumer Electronics Show that "all-IP" was the way to go with digital services.

Theme recurs

(For the record, this is the third time Roberts publicly raised the matter of the Gates CES discussion, and Gates' "all-IP" thinking, since January.)

Far be it from me to attempt to translate the contents of Bill Gates's brain. But where there is confusion, there is occasion to translate.

Just as there are different ways to implement analog technologies and services — your radio tunes in AM and FM frequencies, for example — there are different ways to approach digital technologies and services.

Right now, the bulk of cable's digital services use the technique known as "MPEG-2," in which "MPEG" stands for "Moving Picture Experts Group" and defines the mechanism for squeezing digitized video and
moving it from the headend to the digital set-tops that receive it. (The latter part — moving the compressed information to homes — is what you hear when people say "MPEG transport.")

Some of cable's digital services, like broadband Internet and voice over IP (VOIP), use IP, or "Internet protocol."

Even those two services use MPEG-2 transport to move themselves toward homes.

Shelf-space impact

If you look at it from a bandwidth perspective, it goes like this: Within cable's digital realm, usually located on the "shelf space" between 550 and 750 Megahertz, about two 6-MHz channels carry broadband Internet traffic to subscribing cable modems. Same for VoIP.

The rest of the 6-MHz chunks of bandwidth carry multiple, MPEG-compressed digital video channels — about 10 per 6-MHz channel, as opposed to one per 6-MHz channel in the analog zone, typically located between 54 and 550 MHz.

But nearly all of the 20-million-plus deployed digital set-tops don't contain a cable modem, which is the primary method to convey IP traffic.

The exception: Cablevision Systems Corp. and its Sony Corp. boxes, which contain embedded cable modems.

This whole conversation, by the way, links to related discussions about a Data Over Cable Service Interface Specification signal path to and from digital boxes. (See the March 10, 2003 and March 24, 2003 "Translation Please" columns for details.)

In part, what Gates was saying was something like this: While you're thinking about extending your digital boundaries so as to reclaim analog spectrum and use it more efficiently, also consider moving more and more stuff onto the IP part of the network.

Imagining how this would work tends to tip the brain sideways, because it's way
different than how today's modernized cable systems work.

Here's an example: If you went to all digital, in IP, you probably wouldn't have to worry about chunking things into 6-MHz channels anymore.

All of the digital spectrum between 54 MHz and 750 MHz becomes one big digital channel.

Add a switch into the discussion, and the bandwidth of the one big fat channel between 54 and 750 MHz becomes useable in a very different, on-demand sort of way.

Instead of everything moving in a broadcast sense, from headend to home, whether or not people are watching all of the channels, the bandwidth can be used when people want to use it.

Bandwidth-on-demand, based on what you're doing at the time — surfing the Internet on a cable modem, talking on a voice-over-IP phone, watching a digital TV channel.

But what is IP, exactly? Technically, IP is a subset of a longer protocol, known as TCP/IP, or transmission-control protocol/Internet protocol.

In essence, it's the language of the Internet, used by data communications equipment to speak to one another, so all of the pieces in the chain of Internet-related communications know where and how to send information.

This whole discussion of "all-digital," and the ways to go about it, will be a source of considerable debate and discussion over the coming months and years. As with anything else, there are pros and cons, which hold strategic consequence.

And, because Microsoft is involved, conspiracy theories abound. What's the real intent here? Should I be afraid?

One of the bigger fears, for example, is this: If you treat the modern cable system as one big pipe that accepts connected devices connected that didn't necessarily come from the cable operator (think consumer-electronics gadgetry here), the plant itself could start looking more "dumb pipe" than "smart pipe."

On the other hand, tapping into the innovation happening in the CE and software worlds, using a transport mechanism that is common and growing, holds other kinds of unknown promises.

Either way, it's worth examining, which is probably why Roberts keeps raising the question.

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