News

Why Does A 'DSG’ Matter?

3/07/2008 7:00 PM Eastern

If you spend much time around the people responsible for pushing the software behind Tru2way into more and more cable systems, chances are high that you’ve heard or will hear this one: “DSG.”

The last time this column examined DSG was in March of 2003. Back then, it was “the new new stuff.” CableLabs had just released the specification for it one month prior.

DSG is a nested acronym. It stands for “DOCSIS set-top gateway.” (Marketers, fear not. This is a behind-the-scenes term.)

Boiled way down, DSG is the shuttle bus for command and control information, moving in and out of cable-connected digital devices. “Command and control” is the dull but mission-critical work of the back office: Is this a paying customer? Does this box have the right guide data? Does it need new code — like for tru2way?

“Cable connected” implies a device that contains a cable modem. A set-top with an embedded cable modem, for instance, is equipped to signal with DSG. So are some two-way HDTVs, and so will many of the cross-platform services on the product road map.

Cable engineers consider DSG a far superior method than what they used to use to move data (and still do, in some cases), which, in some cases (read: Motorola boxes) was called “slotted aloha.”

DSG is a headend thing. A pizza box, in a rack. It is widely viewed as the replacement for the 16 million or so boxes out there that only know slotted aloha.

The “go-zinta” (goes-into) of the DSG is the traffic cop for all cable modems: The CMTS, tech-talk for cable-modem termination system.

The “go-zouttas” (outputs) of the DSG are the back-end servers or systems needing the information it shuttles. Maybe you began a video-on-demand session. The request, sent upstream from your house to the headend, moves over the cable modem (and therefore over the Internet Protocol, or IP path), to the CMTS. The CMTS hands it to the DSG: “This is for you.” The DSG takes it to the VOD controller, to begin setting up your session.

As a category, this type of data shuttling is called “out-of-band” signaling. It’s out of band because it doesn’t move inside any particular TV program or network.

For that reason, the engineer inventors who created DSG, five or so years ago, wanted to call it the “DOCSIS Out-of-Band Gateway.”

In shorthand, that’d be the “DOG.”

It just never gets old.

Stumped by gibberish? Visit Leslie Ellis atwww.translation-please.com.

September