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Originally Posted by Sephiroth
You mention fibre. What do you mean by that? BT FTTC (Infinity)? If so, their frequency plan is totally different allowing a faster upstream to be offered.
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I've told you several times before but this is entirely misleading. The "frequency plan" of the two systems cannot be compared in this way, and also the frequency plan has nothing to do with why the two systems offer differing upload speeds and capacities. The term "frequency plan" doesn't even apply in the same way to either technology.
By your reckoning,
VM upstream operates between 18 Mhz and 45 Mhz and contains (up to) 4 upstreams of 6.4 Mhz each
BT upstream operates between 0 Mhz and 17 Mhz and contains two channels of 2.4 Mhz (actually one 1.6 and one 3.2)
How on earth does the latter allow a faster upstream to be offered?
---------- Post added at 11:29 ---------- Previous post was at 11:21 ----------
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Originally Posted by Risco
I know it is something to do with how it works and is the reason why the upload speeds are low and need capping to stop over utilisation. That is about it though!
Wondering how it differs from fibre, and why fibre does not suffer the same issues.
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The real answer is very simple and it boils down to the fundamentals of how the two technologies work.
On Virgin Media cable, your cable is shared with dozens to hundreds of other people. Each cable may have enough capacity for 3 connections' worth and 300 people trying to use it. Virgin Media are counting on you not trying to all use it at the same time.
On BT/Openreach fibre, every single cable is dedicated and provides individual bandwidth to every single user. You get the full capacity of your line all to yourself. You're not sharing your speed between 300 other users.
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Am I right in saying that is a problem that can't be solved?
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Not entirely. VM can break the cable bundles (nodes) down so they are shared between fewer and fewer people, and this is an ongoing effort that all cable companies are trying to achieve - but each step costs exponentially more (although still less than it's costing BT to roll out their completely new fibre network)