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[tickmike]

Did I read somewhere that you should 'Power Off' your Modem/Router than just un-plugging your DSL line when you are changing the Modem/Router configs.

If so is that use the 'power switch' or un-plug the mains lead ?

[roseway]

It's certainly best to power down the modem, and I can't see that it makes any difference which way you do that.

[simoncraddock]

BT's systems can't distinguish between a reboot/power down or loss of synch I was told.

[guest]

BT's systems can't distinguish between a reboot/power down or loss of synch I was told.

The linecard can. Whether BT's management systems can is another matter. Sky's can.

Edit - noticed simon's sig. The reference to Sky's management systems is for ADSL, obviously we're all in the same position on VDSL (FTTC).

[burakkucat]

The best practice would be to power off the modem, thus allowing it to send a "dying gasp" to the DSLAM/MSAN. Then remove the WAN link cable and power the modem back up for any configuration adjustments.

Whether one rigorously follows the above will be directly related to one's experiences! 

[tickmike]

The best practice would be to power off the modem, thus allowing it to send a "dying gasp" to the DSLAM/MSAN. Then remove the WAN link cable and power the modem back up for any configuration adjustments.

Whether one rigorously follows the above will be directly related to one's experiences! 

Sounds good.
Re  "dying gasp" ! so does this get produced when the power supply volts decay quickly either by pushing the power switch or unplugging the mains supply , it then sends this "dying gasp" signal.

[burakkucat]

My understanding of the "dying gasp" is that the device will generate such a signal when the operating voltage falls below a defined minimum.

I'm sure I read in some Beattie documentation (possibly in one of her SINs) about the relevant tests which a modem should pass to be certified as appropriate for use on her network.

[Chrysalis]

I have been doing the following procedure if I need to reboot modem.

cut the power to modem
give at least 30 mins
power the modem up

I have never been DLM'd from doing that.

Likewise when I Swapped to the billion.

power off old modem
configure the new modem (billion in this case) with it "disconnected"
power off the billion after configuring and connect it up
make sure at least 30mins have passed
power up the billion

[les-70]

  Kitz's info suggested that the DLM uses 15min blocks and does not count a friendly error code disconnect (best to power off) if it is followed by a 15 min with no connection.. i.e. off for 30min.   Chrysalis is consistent with that.

[babis3g]

I think it does matter & i think the cabinet can detect the kind of disconnection ... but not sure what is the right way to do ...
example with the broadcom modems there is retrain reason 1,2,8,4000, 8000, 40000 etc ... i am sure is something similar to the cabinet

http://forum.kitz.co.uk/index.php?topic=12504.0

or i am wrong?

[NewtronStar]

The DLM checks the line every 15 minutes, and as we don't know the exact time the DLM last checked your line so we need to use the 30 minute powered off state to make sure it see this on the next check.

[kitz]

Whilst most routers are capable of sending a dying gasp message, and the DSLAM may record the code...... BT deemed several years ago for various reasons that the dying gasp message was not a reliable method for detection of an unforced retrain.

BT's DLM system does NOT take a blind bit of notice of dying gasps - it has its own system to detect what it calls Unforced retrains.

See ~ Detection of sync events & Unforced retrains

Whether BT's system of detecting unforced retrains is more reliable is up for debate, because it only assumes unforced if the EU has a full 15min bin with 0 uptime.

[burakkucat]

But it is still good practice to ensure that a "dying gasp" is sent. Especially as Beattie is not the sole, monopoly, ISP/CP! 

[kitz]

I totally agree..  and note my mention if I think their method is actually more reliable or not.

[JGO]

BT's DLM system does NOT take a blind bit of notice of dying gasps - it has its own system to detect what it calls Unforced retrains. .....

Whether BT's system of detecting unforced retrains is more reliable is up for debate, because it only assumes unforced if the EU has a full 15min bin with 0 uptime.

Thanks for a definitive statement. I'll see if my local BT follows the rules !