Docsis is a technology that increases internet download speeds over existing cable TV lines by selectively sending TV channels to viewers as they request them, rather than broadcasting all station signals to everyone at once. The newest version of the standard, Docsis 3.0, can hit speeds of 160 Mbps, although the fastest speed currently sold is a 50 Mbps system by Comcast.  Traditional DSL which has a speed of 1.5 Mbps.
Demand for internet bandwith and the capacity to support triple play options has spawned two competing ultra high speed internet technologies - Docsis 3.0, which runs over cable television lines, and Fiber to the Premises which delivers high speed internet through fiber optic cables strung directly to the home. Docsis 3.0 is a relatively new technology. It was developed in late 2006 by CableLabs, but it was first released by Comcast in April, 2008.  CableLabs is a non-profit R&D organization that created and oversees the Docsis technology. CableLabs must certify cable modems to be used in Docsis systems and must also qualify cable modem termination sytems (CMTS). Withouth a respective certification or qualification, a company cannot develop products for Docsis. The first qualifications were given to Casa Systems, Arris, and Cisco in December 2007 for their CMTS products.  The first certification for cable modems were given out to Arris, Cisco, Motorola, and SMC Networks Inc. 
Comcast: Comcast was the first cable company to offer Docsis 3.0 when it launched in April, 2008 . Comcast is competing mainly with both FiOS and U-Verse, which use Fiber-to-the-Home (FTTH) technology. In markets where FiOS is present, Comcast is deploying its 50 Mbps system for a price of $150/month.  However, because U-Verse delivers a speed of 10 Mbps , Comcast is delivering a 16 Mbps product in areas with only U-Verse. In comparison, FiOS costs $140/month in most areas, while U-Verse costs $100/month.  Comcast plans to offer 50 Mbp to its entire customer base by 2010.
Review by Joseph Alegre for Rating: I bought this modem the other day bauecse I felt my old SB5101 modem was not optimized for speed. I have a regular DOCSIS 2.0 service through Comcast. The modem made a huge impression on me after it was installed. The download and upload increased around 20 percent. The amazing thing is that this modem squeeze extra bandwidth out of your existing service (weather you have a standard basic megabyte connection or the newer DOCSIS 3.0 service high speed connection). The noticeable difference was the latency speed of the connection. When I click on a link on a web page, the page loads up as soon as the link is clicked. My old SB5101 modem would take a few extra milliseconds to load. What does this mean? If you play video games like Halo 3 via X-box or Call of duty, you will have a reaction time advantage against your competition. The clear negative of this product is that it takes longer to boot-up. If you power cycle the modem or if your internet service provider resets the modem, it will take two minutes to restart. It will take Comcast longer to recognize the modem when you call in to give the Mac address bauecse when they reset the modem remotely, it will take two minutes for the modem to initialize. Once it is online it performs flawlessly. Anyone that buys this modem will benefit from the extra tweaks it has regardless if the are using a basic or super high speed internet service.VA:F [1.9.13_1145](from 0 votes)