Rogers explains ???shaping' policy

[James Knott]

Lennart Sorensen wrote:
> On Thu, Jun 12, 2008 at 07:18:49PM -0400, James Knott wrote:
>> That's due to the way cable bandwidth was set up, long before there were 
>> cable modems. Way back in the B.C (before cable modems) cable TV carried 
>> just that TV and did so (with minor variations) using the same spectrum 
>> as broadcast TV. That spectrum starts at 54 MHz and goes up from there. 
>> Later, when cable companies started getting interested in offering 
>> other, interactive, services, they were placed at frequencies below 54 
>> MHz and used filters to separate the two directions. So, anything 
>> upstream has to fit in that space below 54 MHz, while downstream can use 
>> any part of the spectrum above 54 MHz up to a few hundred MHz. While 
>> some of the details have changed since then, the same situation applies, 
>> when you try to fit TV and upload data on the same piece of coaxial 
>> cable. There isn't much DOCSIS can do about that. This problem does not 
>> exist on the fibre part of the network.
> 
> Hmm, well they could upgrade all their equipment and start using some
> bandwidth above the frequencies used by the television, but of course
> why would they want to spend money on that. :)
> 

That would involve replacing all the coaxial cables.  Fibre to the home 
or at least curb would be necessary and then you'd need new converter 
boxes, TVs etc., to work with the new system.  Also the usable spectrum 
is determined by cable losses.  The higher the frequency, the greater 
the signal loss.  The long term fix is fibre, the short term???



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