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Originally Posted by Jon M
Why delete it?
I'm interested to know what the actual capacity of the infrastructure is, would you like to explain why you think it's wrong?
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Certainly, cable downstreams are a broadcast architecture, that bit of coax is simulataneously carrying 27+Mbit of DOCSIS traffic, even if some of it is padded empty frames, along with all the DTV, analogue, and out of band.
Existing ntl network build specs up to 860MHz, with the range between 5 and 65MHz being used for upstream traffic, that leaves after a guard band of 20MHz the 85-860MHz band to be used for downstream cable traffic.
At nominal 64QAM 6 bits per symbol and assuming a symbol rate of 0.8Megasymbols/MHz just for the sake of argument that gives 775 x 0.8 x 6 = 3.72Gbps capacity, this can be increased further through 256QAM, 8 bits/symbol.
That's just an approximation with regard to Msymbols/MHz, to illustrate.