Reply to post: Re: Smoke and Mirrors

Virgin Media scales back Project Lightning target in first quarter results

AndrueC Silver badge
Boffin

Re: Smoke and Mirrors

Bandwidth may not be the problem, or not in the 'expected' sense. Cable is also often limited by the number of properties that a particular cable services. If a cable happens to pass a lot of properties or several of the properties it passes are particularly heavy users it will adversely impact the performance of all the properties on that cable. The only solution in that instance is to split the cable by installing additional nodes. Unfortunately that requires relatively costly civils so cable companies don't rush to do that.

Cable was originally intended for multicast use - TV services. As such its topography is ideal because just one TV signal can feed multiple properties. But internet use requires unicast and there cable suffers somewhat. A single coax cable has way more bandwidth than a single twisted-pair telephone cable. But a telephone cable only has to service one property. Sometimes (not often) that can lead to a good FTTC connection offering a better experience than a cable connection at peak times.

The biggest issue though is in upstream speeds. Cable has to use TDM to synchronise the user modems. This causes various issues that together explain why cable upload speeds are often a bit poor compared to xDSL.

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