Kitz Forum
Broadband Related => Broadband Hardware => Topic started by: digitalnemesis on April 20, 2016, 09:39:42 PM
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Is it better to unplug the power cable or the RJ11 cable when switching modems?
Wait 30 minutes or more to be safe?
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Is it better to unplug the power cable or the RJ11 cable when switching modems?
Wait 30 minutes or more to be safe?
Well, coming from someone who wanted to induce it, you probably won't trust me. :lol:
Anyway, I always power off the modem then switch modems and yes leave it for 30 minutes just incase, though 1 disconnection won't evoke DLM.
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I would say that it is best to pull the power lead. If you only do one reboot then it probably isn't necessary, but otherwise it is a wise idea to wait 30 mins with the modem off, to get over the next 15 min time period boundary.
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Is it better to unplug the power cable or the RJ11 cable when switching modems?
Wait 30 minutes or more to be safe?
Always pull the dsl lead first. Never had an issue that way provided I go with the 31 minute rule.
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I have to disagree with the above. If you only do it occasionally it will probably make no difference, but the safest from a DLM point of view is to power down the modem.
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I have to disagree with the above. If you only do it occasionally it will probably make no difference, but the safest from a DLM point of view is to power down the modem.
Is there a shutdown command for the HG612?
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Hi
I have to disagree with the above. If you only do it occasionally it will probably make no difference, but the safest from a DLM point of view is to power down the modem.
Is there a shutdown command for the HG612?
If you can telnet in to a modem and it's Broadcom then:
xdslctl connection --down
Feels like a nice way to disconnect, then power down or reboot the modem. On rebooting or restarting the connection will come back up.
Regards
Phil
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No such command as XDSLCTL use XDSLCMD instead
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It depends on the modem firmware, it may be called xdslctl on some devices.
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There are several different command prefixes, depending on the hardware manufacturer. If you scroll down this page (http://www.s446074245.websitehome.co.uk/configuration.html) you'll see a selection of them.
(Note to self: it's time I updated that in respect of 'routers'.)
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Hi
I have to disagree with the above. If you only do it occasionally it will probably make no difference, but the safest from a DLM point of view is to power down the modem.
Is there a shutdown command for the HG612?
If you can telnet in to a modem and it's Broadcom then:
xdslctl connection --down
Feels like a nice way to disconnect, then power down or reboot the modem. On rebooting or restarting the connection will come back up.
Regards
Phil
What does that do exactly? Does it send a last gasp for DLM to pick up?
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Interestingly BT OR engineer was here yesterday. He did not power down the modem. Just removed the dsl lead. In fact he didn't even reboot the modem before plugging it back in or wait 30 mins before resyncing the modem without performing a dlm reset . The result actually resulted in a 1mb increase on the ds :lol:
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DLM itself does not use dying gasp....
However I read in some BT doc or other (cant recall for the life of me where) that dying gasp can be used by the ISPs to check that a customer has powered down a modem when told to do so as part of their fault finding process.
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I may be wrong ............ but I can't ever recall in all the years of BB faulting, receiving any info from the Chief Engineers Office regarding the 'Dying gasp', and/or unplugging the power first before working on the circuit ?.
I'm not saying whatsoever that it does or doesn't play a part, I'm simply surmising as to the impact of unplugging the DSL lead first as opposed to cutting the power, due to us not receiving any guidance from them above ?? They usually inform us rapido-style if something has been found that would seriously affect the circuit ? :-\ :-\
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We forgot to mention this when you have done a 30 minute power off you must leave the modem on for another 30 minutes before the next power off
This should give you a retrain reason 0 each time if you don't you will see a retain reason 1 which is not good.
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Openreach probably doesnt care, if it does not make any difference to the DLM or BT side of things.
Wish I could recall where I saw that ISP's may use it during troubleshooting :( :-[
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Found something about it.
Is this new as its the first reference I've seen in SIN 498 about this.
Cant find a changelog but earliest ref I can see to SIN498v7p1 appears to be Feb 2016
SIN 498
Note: “Dying gasp” is not a mandatory requirement but CP’s are encouraged to
implement this in their modems as it will enable the Openreach Test & Diagnostic
systems to differentiate between a modem being turned off by the end user
(loss of power) or a loss of signal (loss of connectivity) caused by a potential network or home
wiring issue.
This will support CPs in their diagnostic approach to ensure that their
End Users have checked the relevant setup prior to submitting a fault to Openreach,
thus avoiding a potentially chargeable engineering visit.
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That's the one. Spot on!
Cheers love :D
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Hi
The 15 minute so waiting 30 minute before reconnecting doesn't matter surely for a few re-syncs in a row. I've never waited any time before connecting and reconnecting and have made several connections/disconnections with minutes and it's made no difference.
Surely the DLM logic is clever enough to know what interventions are required based on error rates only? If a plug is pulled so all VDSL signal is completely lost (or power turned off), surely it would know by a complete absence of signal that no matter what intervention it could apply in the way of interleaving, G.INP, banded profiles etc it isn't going to allow the VDSL signal to jump through the air and find it's way back into the RJ11 plug laying by the socket disconnected? They must have something in place to know the lead has been pulled or power turned off and for that to be ignored by the DLM?
Is this an urban type myth thing, the 15 minute window, or do we know it really exists? It sounds like something that would be a stupid thing if it was true.
Regards
Phil
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Hi Phil,
If you do 20 connections or more within 24 hours, DLM will then take action.
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@PhilipD
I can guarantee that BT's use of 15 min bins to detect unforced retrains for DLM is absolutely true.
Theres more info about how DLM decides what is and what isnt an unforced retrain here, and how it uses the 15 min bins here:
DLM process - Detection of sync events (http://www.kitz.co.uk/adsl/DLM.htm#dlm_sync_events) &
DLM process - Check for Unforced Retrains (http://www.kitz.co.uk/adsl/DLM.htm#unforced_retrains)
DLM uses the MTBR calculation to decide whether to take action on what it decides as too many unforced retrains. MTBR = uptime/no of unforced retrains.
You are correct that it will ignore 'x' amounts of retrains per day. 'x' depends upon your days uptime and the stability level set by your ISP.
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yeah I got no doubt about the 15 min bin's.
Nice find on the dying gasp thing, I will continue to always pull power, and leave for 31mins+ process.
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I have always swapped modems and modem/routers as and when i have liked even when i was on normal ADSL, i have never bothered waiting any time and i have never had any problems with the DLM playing up, i just don't think i'm doing it enough times in one to day to matter.
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>> Nice find on the dying gasp thing,
Im sure Ive read SIN 498 numerous times and not spotted that paragraph before.
I was trying to find a change-log to see the data of change and what they changed, but there didn't appear to be one.
The only thing I could find from a quick scan is that the first reference to SIN498v7p1 was Feb this year.
A search on that paragraph only pulls up SIN498v7p1, but that in itself isn't conclusive evidence that is when they added it.
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The change log for BT SIN 498 is in the SIN document itself, before the long annexes with the test procedures. It says it was added in v5 dated June 2013, which is the oldest version I have a copy of. The paragraph about dying gasp is in the Ethernet OAM section, the optional requirement to support dying gasp is R.OAM.4, perhaps it has seen little attention because most people concentrate on the VDSL2 requirements section.
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Thanks ejs.
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xdslcmd connection --down
works on HG612 after sh
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On the HG612 the commands begin with 'xdslcmd', so 'xdslcmd connection --down' should work. Sorry if you know this perfectly well, but you do have to enter 'sh' at the ATP> prompt to get to the Busybox shell where you enter the xdslcmd commands.
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We forgot to mention this when you have done a 30 minute power off you must leave the modem on for another 30 minutes before the next power off
This should give you a retrain reason 0 each time if you don't you will see a retain reason 1 which is not good.
What's the difference between retrain reason 0 and 1?
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On the HG612 the commands begin with 'xdslcmd', so 'xdslcmd connection --down' should work. Sorry if you know this perfectly well, but you do have to enter 'sh' at the ATP> prompt to get to the Busybox shell where you enter the xdslcmd commands.
Thanks, I forgot to do that. :lol: