Note: NTSC 6 MHz channel spacing will allow 10 bonded 6 MHz channels as MAX spectrum allocation for DOCSIS3.0 data, 60 MHz spectrum allocation could increase with consumer needs and re-allocation of analog TV channels into compressed digital space, leveraging the capability of DOCSIS 3.0 infrastructure to allow for 1 Gbit/s speeds in the future.
Any geek will tell you that there’s no such thing as “too fast” when it comes to broadband speeds, and that’s why the recent DOCSIS 3.0 spec is exciting to cable modem users. The new version of DOCSIS (Data-Over-Cable Service Interface Specifications) will allow for jaw-dropping physical layer speeds of 160Mbps downstream and 120 Mbps back up—more than a fourfold increase over current rates.
One of the problems with Comcast’s new DOCSIS 3.0 service is that it is simply too fast. At 50Mbps download speed (and 5Mbps upload speed) your service will be going faster than most web sites can deal with. This means it is very hard to do a proper test to see if you’re actually getting the 50/5 service that you paid for. Think the SpeakEasy.net speedtest can help? Depends on how close you are to a node.
The solution is simple. If Comcast had some sort of super-secret internal speed test page that would allow you to see the speed that the Comcast network is sending you before it hits the public Internet, that sure would be helpful, wouldn’t it?
Take your new DOCSIS 3.0 connected computer, open a web browser and point it to http://68.87.178.6 to get the Comcast internal speed test page. This will test the speed of your cable router inside of the Comcast network allowing you to see the raw speed as it goes to your house.
source: wikipedia.org