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[roseway]

The question arose in this thread, about how DLM responds to the router being switched off periodically, and there was some disagreement which I would like to explore further to try to get to the truth. Basically one party says that switching off the router a few times a day will not trigger DLM into raising the target noise margin, and another party says that even switching it off once a day at night will trigger a response from DLM, which will eventually result in a substantial reduction in the connection speed.

This isn't personal, by the way, and I'm quite happy to be shown to be wrong, but I would welcome any contributions to the debate.

[razpag]

Thanks Eric.

Also, on the back of this, Eric stated that in the early days of Broadband, most routers were USB powered and as such were switched off as soon as the PC/Laptop was switched off. Back then though, only fixed-rate Broadband was available and wasn't tied-in to the DLM management sytems we now have on rate-adaptive products.

So, my belief (and that of all SP's) is that by turning the router/Hubs off on a regular basis, ie- every evening, then one's speed will suffer enormously after a certain period of time. I'm not saying that turning it off every now and again will affect it, but at least once a day will !!

As per Eric's comments, it's in no way personal .............. I just know I'm right. 

[roseway]

Also, on the back of this, Eric stated that in the early days of Broadband, most routers were USB powered and as such were switched off as soon as the PC/Laptop was switched off. Back then though, only fixed-rate Broadband was available and wasn't tied-in to the DLM management sytems we now have on rate-adaptive products.

I accept that point.

But on reflection, not entirely. As HP says below, lots of USB modems were still in use when rate adaptive ADSL started up.

[HPsauce]

Although, just to confuse things, many USB ADSL modems were fully capable of working on rate-adaptive lines at the same speed as a standalone modem-router, and I've seen many in exactly such use.

For BT's DLM to not cope properly with that scenario would be a major oversight.  

(not that many around now though)

[silversurfer44]

I've got a green frog!

[roseway]

So, my belief (and that of all SP's) is that by turning the router/Hubs off on a regular basis, ie- every evening, then one's speed will suffer enormously after a certain period of time. I'm not saying that turning it off every now and again will affect it, but at least once a day will !!

This is the point which I dispute. Anyone who becomes the subject of a discussion between their ISP and OR will have some sort of undiagnosed problem with their connection. It may well be assumed that the fact that some of them turn off their router periodically is a contributing cause of the problem, but that's a long way short of proven.

Over the years I've seen many examples of people who regularly turn off their routers at night with no ill effect. I can't think of any reason why the designers of DLM would want to make it so sensitive to something which lots of people will want to do, if only for 'green' reasons (or 'granny' reasons ).

[bbnovice]

Hi:

Smacked wrist for me for posting in the wrong thread, but here is what I wrote regrading the DLM question:

....and a fixed rate is what I have now. I was put onto a 4mb speed (12db) fixed speed as part of the trouble shooting/resolution when I recently had a bad network issue. And personally its suits me perfectly - the connection is stable and now performs very well (touch wood). Bearing in mind that I'm a bit of distance from the exchange I would rather have much improved stability/reliability at the expense of sacrificing some speed. And it means I can turn the router off at night !

Being controversial - Is the DLM worth it unless you have a need for utmost speed?

 

[HPsauce]

I've got a green frog!

I've got a Tiscali Speedtouch 330 and Vista drivers - I can even make it work with Windows 7 64-bit!
(not that I want to - it was just an academic exercise)
But they are still out there so it would be really good to know "the truth".

[razpag]

http://uk.answers.yahoo.com/question/index?qid=20101105095925AAZn083

http://www.diynot.com/forums/viewtopic.php?p=1969280&sid=b34fbc06ac850b9e9a66b92db9ed08fe

2 quick web finds ...........

[razpag]

TBH , for every web page I find backing up my sentiments, there's another stating different.

I think there's clarity needed here. I'm saying that if the Hub/Router is turned off every night until the following morning, not switched off then back on again as a lot of the threads seem to infer.

To reiterate, when I have co-op calls with the ISP's they also concur with the fact that switching ones modem off on a daily basis is detrimental to the circuits health.

[Archie]

Hi Guys,

This is an interesting discussion going on.  I just noticed it.

So, when I go on holidays for a week or two, I can turn the router off (for safety reasons) without any worries of being penalised by the DLM.  Am I correct in this assumption?

Archie.

[razpag]

Yes.

IMHO (and the SP's), the DLM likes to be able to 'talk' with the router/Hub at all times. The key is stability. If you turn it off once for 2 weeks, this is hardly 'an ongoing issue'. If however, you turn it off each and every evening for long periods, the DLM quite rightly 'sees' this as an underlying fault and raises the SNR steadily until it acyually 'caps' the line at it's lowest speed.

Please, please do not take my word for this. Ring your SP's techy peeps and ask them.

[jeffbb]

Hi

I used a Speedtouch 330 when I first upgraded to 8 Max and had no problem with the target SNR .Had plenty of problems with Tiscaly though,but that was another tale of woe .

Regards Jeff

[HPsauce]

I used a Speedtouch 330 when I first upgraded to 8 Max and had no problem with the target SNR .Had plenty of problems with Tiscaly though,

Me too on both counts; 8128kbps sync but it was traffic management nightmare every evening. 

[roseway]

the DLM quite rightly 'sees' this as an underlying fault and raises the SNR steadily until it acyually 'caps' the line at it's lowest speed.

There are two things wrong with this:-

- it's not "quite rightly" if the router sends the dying gasp message to inform DLM that it's doing a power down. It's my understanding that most ADSL routers do send the dying gasp message, but I have no hard information to back that up.

- DLM doesn't keep on slowing down the connection until it gets to the lowest speed. It increases the target noise margin to a maximum of 15 dB, and the eventual connection speed is whatever results from that noise margin on the line in question.

To reiterate, when I have co-op calls with the ISP's they also concur with the fact that switching ones modem off on a daily basis is detrimental to the circuits health.

I'm not doubting that this has been your experience, but I do question whether the ISP reps who agreed with this were really technically qualified. If they were the typical first line support staff employed by the big ISPs then their technical opinions don't really rate very highly. I'm hoping that one or two of the reps with real technical knowledge will contribute here.