dslreports logo

story category
Comcast Upstream Tests: 75-100 Mbps
Upstream DOCSIS 3.0 channel bonding finally coming together...
by Karl Bode 03:51PM Friday Feb 26 2010
The first incarnation of the cable broadband DOCSIS 3.0 standard is theoretically capable of 160 Mbps downstream, and 100 Mbps (shared). But upstream channel bonding has been hard to perfect for hardware vendors and MSOs, which is why you see strangely top-heavy cable broadband tiers like 50/5 Mbps, or even in some cases 100/2Mbps. But we're finally starting to see some movement on this front, and faster upstream speeds should finally be coming your way later in 2010. Comcast is busily testing bonded upstream service and says their tests are providing a consistent 75 Mbps upstream connection:
lab and field trials of upstream Docsis 3.0 channel bonding have produced "sustained rates" of 75 Mbit/s to specific service groups, Chris Bastian, the MSO's executive director of network architecture, revealed here Thursday on a panel focused on what's next for cable's wideband platform. "The results look very good," he said of Comcast's attempt to bond up to four channels in the upstream. The test results have been even better in more controlled lab settings, where Comcast has been able to create sustained bursts of 100 Mbit/s.
According to Comcast, the difference between the field and lab upstream speeds are due to the channel widths used to conduct the tests: the combination of two 6.4MHz-wide channels with two that are just 3.2MHz wide in the field, and the bonding of four 6.4MHz-wide channels in the lab. Comcast CTO Tony Werner had originally been telling reporters that faster DOCSIS 3.0 speeds would drop during the first quarter of 2010, but all indications are now that an upstream bump for Comcast customers won't occur until the second half of this year.

143 comments .. click to read