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DOCSIS

Speed Thrills

5:50 PM -- UPC Cablecom , Switzerland's largest cable MSO, is the latest operator to don the mad scientist smock and test the boundaries of Docsis 3.0. Cablecom says its experiment hit downstream bursts of 1.37 Gbit/s in a lab trial, just a tick below the 1.4 Gbit/s that Norway's Get got in a trial revealed last month. (See Get Tests 1.4-Gig Speeds.)

But why is cable getting all hot and bothered lately about lab trials that are reaching speeds that are as practical as a seven-lane freeway running through Boise, Idaho? Just to demonstrate what kind of speed difference we're talking about here, Cablecom's current high-end D3 residential tops out at 100 Mbit/s downstream -- not even 10 percent of the speeds produced by the trial.

At this point in the game, it's all about giving the world another example of D3's longer-term potential, and perhaps sending a somewhat subtle message to cable investors that the industry's hybrid fiber/coax (HFC) networks still have plenty of legs left before MSOs will have to spend big money to pull fiber all the way to the home.

But let's not kid ourselves, either. This also has a little something to do with bragging rights -- unless anyone has forgotten that Cable Congress 2011 is getting underway in Lucerne (Zurich) this week, so there's no time like time like the present for the host MSO to talk up the results of its latest engineering handiwork.

This time around, though, we actually did learn something new -- how Cablecom, which is part of UPC Broadband , achieved these speeds in the lab.

According to a Cablecom spokesman, it hit the mark by bonding 32 8MHz-wide downstream EuroDocsis channels. No single Docsis modem exists to do that yet, but Cablecom did it by combining four Cisco Systems Inc. (Nasdaq: CSCO) modems that could each bond eight channels. Those were linked up to the Cisco flagship cable modem termination system (CMTS), the uBR100012, equipped with the vendor's new 3G60 line card, which packs in 72 downstream ports. (See Cisco Aiming to One-Up Cable's Upstream .)

So it was largely done with existing equipment while giving us a glimpse at D3's future. Today's state-of-the-art D3 chipsets bond eight downstream channels, but there's still a debate on what Intel Corp. (Nasdaq: INTC) and Broadcom Corp. (Nasdaq: BRCM) should target next. I hear chips integrated with the ability to bond 16 or 32 downstreams are both candidates for the next big spin. But, given the direction of the most recent D3 speed trials, I'd start putting my chips on 32.

— Jeff Baumgartner, Site Editor, Light Reading Cable

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