Rogers explains ???shaping' policy

[Duncan MacGregor]

How much of the network is fibre already?




On Friday 13 June 2008 14:30:51 James Knott wrote:
> 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???



-- 
Duncan MacGregor    --- Toronto ---
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