120M : Virgin Media dropping fibre internet ad for Docsis 3?

[qasdfdsaq]

Originally Posted by tweetiepooh

Surely for the distances involved the speed of electrons in wire and photons in cable are ALMOST irrelevant. It's how fat the pipe is.

Correct, how fat the pipe is and how you talk through the pipe matters. Most (>90%) of the latency is caused by the bridges, amplifiers, and repeaters.

[Pierre]

Originally Posted by qasdfdsaq

Correct, how fat the pipe is and how you talk through the pipe matters. Most (>90%) of the latency is caused by the bridges, amplifiers, and repeaters.

And DCF, but Bragg gratings have improved.

Latency in general is just to do with how long the cable is.

A new low latency trans-Atlantic cable is currently being installed, it's secret? It's shorter than all the others (and fewer repeaters).

A few milliseconds advantage for an algorithmic Stoke trade = £100millions

[qasdfdsaq]

Originally Posted by Pierre

And DCF, but Bragg gratings have improved.

Latency in general is just to do with how long the cable is.

A new low latency trans-Atlantic cable is currently being installed, it's secret? It's shorter than all the others (and fewer repeaters).

A few milliseconds advantage for an algorithmic Stoke trade = £100millions

Yeah, the number I hear being bandied about is 1ms of latency is worth about £5m a year to HFT companies.

The transatlantic paths are getting quite close to the theoretical maximum speed now based on the speed of light, with previous gen cables still giving round-trip latencies 20-40% higher than the cable length alone would suggest. The claimed 55-60ms RTT from London to NYC on the latest gen cables come within 10% of the absolute best we'll ever get, unless someone embeds an open-air a waveguide through the earth's mantle.

However paths on the other side of the world are still slow enough that less than half the round trip time is attributable to actual signal propagation along the fibre.

But I digress. In the home broadband environment, most of the latency in the last mile comes from the bridging devices at either end - i.e. the modems, DSLAMs, and CMTS.