A new Docsis 3.0 chipset from Broadcom Corp. (Nasdaq: BRCM), capable of bonding 16 downstream channels, will enable cable modems to close in on speed bursts approaching the 1-Gbit/s mark.

That chip, based on the BCM3380, basically doubles the downstream throughputs of eight-channel Docsis 3.0 modems and embedded multimedia terminal adapters (EMTAs) that are just now coming on the market from Arris Group Inc. (Nasdaq: ARRS), Cisco Systems Inc. (Nasdaq: CSCO), Motorola Inc. (NYSE: MOT), and several other key Docsis modem suppliers. Broadcom is teaming that super-wide downstream with a four-channel upstream (D3 specs require modems to support a minimum of four bonded upstream and downstream channels). (See Arris Launches 8x4 Wideband Gear.)

Update: Broadcom has since clarified that the 16-channel "solution" it's touting is in fact a prototype of sorts that ties together two separate BCM3380 Docsis 3.0 chipsets that are each capable of bonding eight downstream channels, and does not represent the introduction of a newly integrated D3 silicon. Big difference. A story with more details on Broadcom's 16-channel proof-of-concept and what it might have in store later can be read right here.

It's likely that operators won't use a full 16-channel configuration for raw Internet throughput, but will instead dedicate a portion of capacity to support managed IPTV and over-the-top Web TV services piped to Docsis 3.0-enabled set-tops and a new breed of whole-home transport gateways.

However, if an operator were to use the full downstream load provided by the BCM3380 strictly for a straight broadband Internet service, an operator could conceivably achieve product burst speeds of 640 Mbit/s on North American Docsis systems, which use 6MHz channel spacing. Those theoretical bursts could jump to 800 Mbit/s in EuroDocsis environments, which use 8MHz channel spacing. Virgin Media Inc. (Nasdaq: VMED), which uses EuroDocsis configurations, still holds the D3 downstream speed high watermark via its ongoing 200-Mbit/s trials in the UK. (See Virgin Bonds With 200 Mbit/s Trial .)

Broadcom has yet to say when it will try to obtain CableLabs and Cable Europe Labs certification for the new chipset, but initial deployment traction will likely be found in Europe, where MSOs are starting to rapidly pursue broadband-driven IPTV services.

Case in point: Broadcom's unveiling the chipset at this week's ANGA Cable show in Cologne, Germany, and isn't exhibiting at The Cable Show next week in Los Angeles, though some of its execs will be doing meetings and roaming the floor, we're told.

The availability of gateways and modems with the new D3 chip is still likely months away, but Broadcom's move to support 16 bonded downstream channels should give it a brief leg up on Texas Instruments Inc. (NYSE: TXN), which has already developed an 8-channel wideband modem chipset. (See TI Flexes Docsis 3.0 Muscle .)

TI, however, indicated last fall that a 16x4 Docsis 3.0 chipset is on its roadmap. [Ed. note: We've asked TI for an update on when it expects that product to become available.]

— Jeff Baumgartner, Site Editor, Light Reading Cable