updated 08:55 am EST, Tue February 23, 2010
Bursts up to 250Mps may be possible
A source at cable service provider Comcast says the company is making improvements to its Internet service that will provide 20 percent of its subscribers with 100Mbps download speed by the end of the year. Enhancements to the company's existing DOCSIS 3.0 modems and cable systems make the higher data transfer rates possible, according to BBR. Comcast has already upgraded 90 percent of its coverage area to get the option of 50Mbps download speeds but has only rolled out 100Mbps in a single market.
Until 2007, cable modems were only capable of maximum downstream data transfer rates of 36Mps through DOCSIS 2.0. The 3.0 technology cable bonds together multiple channels in both directions to provide additional bandwidth and theoretically supports rates of 160Mbps for downstream data and 100Mbps upstream, with downstream bursts of up to 250Mbps possible; it's likely any Comcast 250Mbps service would focus on this temporary speed rather than a sustained faster speed.
Upgrades to the cable modem termination system, which links the cable network hub and the customer's cable modem, also have to be made before the higher speeds can be realized.
No mention has been made of either the 100Mbps or 250Mbps tiers getting an increase to the bandwidth cap, which at 250GB is widely considered low for the faster tiers. Comcast has been rolling out a bandwidth meter to a handful of areas but has no provisions to increase the available bandwidth.