Kitz Forum

Broadband Related => FTTC and FTTP Issues => Topic started by: adslmax on February 05, 2015, 11:51:57 PM

Title: Swapping Modems
Post by: adslmax on February 05, 2015, 11:51:57 PM
Does anyone know what are the maximum of swapping modems in the space of 2 hours (if the modems is powered down for at least 30 minutes in between) to avoid any DLM overnight.

Title: Re: Swapping Modems
Post by: jid on February 06, 2015, 12:32:26 AM
Does anyone know what are the maximum of swapping modems in the space of 2 hours (if the modems is powered down for at least 30 minutes in between) to avoid any DLM overnight.

In general, DLM measures in 15 minute windows. So it's though that leaving 30 minutes makes sure the modem is powered down for at least one window. As you won't know if you're in one or the other.

So for example, you turn off your modem at 15:30, and then reconnect at 16:01. You'd need to leave till 16:31 until you disconnected again and so on.

9 resyncs per day are acceptable on the DLM Standard profile - see the calculator here (http://www.kitz.co.uk/adsl/DLM_calculator.php).

Hopefully this makes sense? If you do the maths, you need 30 mins of power down per swap, so in 2 hours, you *could* swap the modem twice. Obviously, this isn't a confirmed calculation, DLM is mystery :)
Title: Re: Swapping Modems
Post by: burakkucat on February 06, 2015, 12:45:29 AM
I would agree that in any given a two hour window, a maximum of two complete modem swap-outs would be possible.
Title: Re: Swapping Modems
Post by: b4dger on February 06, 2015, 05:49:16 PM
I'm dreading this summer's storms when my overhead line picks up MASSIVE amounts of noise...

I guess BT aren't aware of the havoc storms cause to ADSL/VDSL/DLM  :no:
Title: Re: Swapping Modems
Post by: adslmax on February 06, 2015, 06:09:25 PM
Thunderstorms last summer doesn't affect my FTTC DLM.
Title: Re: Swapping Modems
Post by: kitz on February 06, 2015, 09:55:35 PM
I guess BT aren't aware of the havoc storms cause to ADSL/VDSL/DLM  :no:

See Wide area events (http://www.kitz.co.uk/adsl/DLM.htm#wide_area_events)
Title: Re: Swapping Modems
Post by: b4dger on February 07, 2015, 02:49:36 PM
See Wide area events (http://www.kitz.co.uk/adsl/DLM.htm#wide_area_events)

Thanks - My exchange went from ADSL (20CN) > FTTC skipping 21CN. The 'wide area events' didn't seem to work well (if at all!) when I was on ADSL - so I'm hoping now I'm on FTTC the DLM will work better.  The number of errors and amount of noise picked up when a storm approached (when on ADSL) was incredible and if kit was left powered on the recovery from a low sync took the normal 'up to 5 days' (20CN)...
Title: Re: Swapping Modems
Post by: NewtronStar on February 07, 2015, 07:23:49 PM
Lets say someone wanted to test out two modems/routers at the same we know there is only one DSL cable from the master socket to modem, was just thinking if you could split the single DSL cable and make two DSL plugs though the signal may degrade by half on each DSL plug  :(
Title: Re: Swapping Modems
Post by: burakkucat on February 07, 2015, 08:01:06 PM
You are absolutely correct in your last assumption. The "not powered on" modem will be shunting the line and effectively acting as a form of bridging tap to the currently "powered on" modem.

Messy.  :-X
Title: Re: Swapping Modems
Post by: NewtronStar on February 07, 2015, 09:12:11 PM
Thanks - My exchange went from ADSL (20CN) > FTTC skipping 21CN. The 'wide area events' didn't seem to work well (if at all!) when I was on ADSL - so I'm hoping now I'm on FTTC the DLM will work better.  The number of errors and amount of noise picked up when a storm approached (when on ADSL) was incredible and if kit was left powered on the recovery from a low sync took the normal 'up to 5 days' (20CN)...

It will work b4dger as last years T/Storms were bad loads of CRC's and ES's yet the DLM on my FTTC didn't bat an eyelid so this part of the DLM is working well for the end-user  ;D
Title: Re: Swapping Modems
Post by: b4dger on February 08, 2015, 02:30:43 PM
It will work b4dger as last years T/Storms were bad loads of CRC's and ES's yet the DLM on my FTTC didn't bat an eyelid so this part of the DLM is working well for the end-user  ;D

 :) Sounds promising!