Why kernel development still uses email

Posted Oct 16, 2016 8:35 UTC (Sun) by farnz (subscriber, #17727)
In reply to: Why kernel development still uses email by Wol
Parent article: Why kernel development still uses email

Just a nit - that's nowhere near the best available over copper. Using BT's copper wires (but paying AAISP for service, as they're extremely clued), I get 80M down, 20M up reliably. Helps that the copper stretch to the DSLAM in the cabinet is very short, but still, it's VDSL2 over copper (which BT sell as BT Infinity "Fibre Broadband", even though it's over copper), not fibre to the home.

And I don't have problems keeping the connection working - although relatives in the area using BT Broadband do. Changing which ISP the circuit is backhauled to does seem to help in the UK.

Why kernel development still uses email

Posted Oct 16, 2016 14:03 UTC (Sun) by Wol (subscriber, #4433) [Link] (3 responses)

But you're over mixed copper/fibre. That option is not available to me.

I don't have a cabinet to house a DSLAM and fibre link ... As I said, I have the best available connection over copper :-)

Mind you, if we move in the not too distant future (highly likely it looks like now) I shall almost certainly change ISP away from BT. My in-laws (on the same exchange, possibly also with no cabinet, like me) also get terrible connectivity with a different ISP.

Cheers,
Wol

Why kernel development still uses email

Posted Oct 16, 2016 14:06 UTC (Sun) by farnz (subscriber, #17727) [Link] (2 responses)

You're also on mixed copper/fibre, though - the DSLAM you're connected to (which isn't giving you the top speed of ADSL2+ - I've had higher sync speeds on ADSL2+ in the UK) is connected to the rest of the network by fibre, just like mine.

Why kernel development still uses email

Posted Oct 19, 2016 16:10 UTC (Wed) by Wol (subscriber, #4433) [Link] (1 responses)

So if the technical infrastructure is allegedly the same, why can't I get BT Infinity?

Okay, with no cabinet it's obvious why I can't get FTTC, but why can't I get the same speeds to the DSLAM in the exchange?

Cheers,
Wol

Why kernel development still uses email

Posted Oct 19, 2016 16:18 UTC (Wed) by farnz (subscriber, #17727) [Link]

Because the DSLAM in the exchange is configured to use a bandwidth of up to 2.2 MHz depending on line length; higher bandwidths are unacceptable, due to the RFI issues they cause in the exchange for other lines in the same bundle.

The DSLAM in a cabinet is configured to use a bandwidth of up to 17 MHz depending on line length; unlike exchange based DSL services, this presents no significant RFI issues, as the affected lines are all connected to the same DSLAM anyway (and thus would get the RFI at any permitted bandwidth.

In both cases, you have fibre to a DSLAM, copper from DSLAM to your home, signalling rate of 4 kilobaud. It's just that the permitted bandwidth is higher if the DSLAM is in the cabinet, and thus the numbers of bits per symbol is much higher.