Newest Cable Chapter Enables An Array Of Applications
Leslie Ellis -- Multichannel News, 8/31/2008 5:26:00 AM

By now, the channel-bonding feature of the newest cable modem chapter, known in tech-speak as DOCSIS 3.0, should be pretty evident. Benefit: Ramming speed.

Channel-bonding is what lets you download a movie, or 40 pounds of encyclopedias, or anything else with bit bulk — in the time it takes to boil an egg.

The math of it goes like this: Each 6 MHz channel, slinging information using 256-QAM (quadrature amplitude modulation), can carry 38.8 Megabits per second of data. Bond two channels for 77.6 Mbps; three for 116.4 Mbps. A four-channel bond, at 256-QAM, yields a blistering 155.2 Mbps in downstream, toward-the-house speed.

And so on, all the way to the end. The end, in the case of a cable system built to 860 MHz, is 134 downstream 6 MHz channels. (The math: 860 minus the 54 MHz of the upstream path, divided by the 6 MHz channel width.)

If you bonded all 134 channels, you'd have a downstream pipe capable of 5.2 Gigabits per second. (Note: The channels need to be empty before you can do any kind of willy-nilly bonding.)



Translation Please: DOCSIS 3.0 + PacketCable 2.0 = Cross Platform - 8/31/2008 5:26:00 AM - Multichannel News