| Quote from: Andrue |
| Quote from: chenks76 | | 1) to say it won't bother DLM is misleading. it may eventually "bother" DLM |
No, it won't. We know enough about DLM to be absolutely certain that turning the modem off overnight will not trigger a DLM response.| Quote | | 2) constant turning off and on may lead to premature failure of the router |
Unlikely. I've been doing that for all my low power equipment for years now and this Monday's switch failure is the first of any kind that I have known.| Quote | | 3) powering the router off would stop ALL devices having access, not just the childrens devices. |
Yes, that much is true.
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Actually chaps you are both partly right and partly wrong. Taking the points in reverse order -
3) Obviously when it's off, no-one has access, but parents (or others by permission) may want access later than the children.
2) Turning things on and off does stress components and is more likely to cause earlier failure than if there is no switching.
However, a lot of modern equipment is designed to be "soft-start" so there aren't the same surges that you might otherwise get. That unfortunately isn't true of a lot of "budget" devices, and generally it's only "designed in" to more complex items of equipment such as TV sets etc. and a lot also depends on the quality of components used in the first place.
Then there's a trade off between how long the equipment is on and being used. The failure rate of components depends on not only how long they are powered up, but also how much margin there is within their design parameters - eg. maximum power ratings, temperature limits etc. A component used nearer it's maximum limits is more highly stressed and therefore likely to fail sooner. Sometimes the failure rate for the equipment due to switching is much lower than the failure rate due to it being powered 24/7 and there isn't always any way of being certain. How physically hot a piece of equipment runs is certainly one indicator.
It all contributes to the overall Reliability (or MTBF if you prefer).
1) Switching off overnight - always a thorny issue. It's important to distinguish whether one is talking about a combined modem/router or just a router - too many use the generic term router when it's actually a modem/router. Turning off a separate router should not be an issue. If the modem is maintaining sync, DLM doesn't even enter the picture.
So for combined modem/routers and separate modems, it firstly can depend on how many errors you get on your connection - most users won't know unless they have access to the detailed stats (and understand them), nor is it normally possible for a user to know whether DLM regards a particular combination of say errors and noise margins as being critical so that one other (undesirable) event causes it to act. A loss of sync (by switching off) might be such a trigger in some circumstances.
Then there's the length of the connection (to the Cab for Fibre, exchange for ADSL) and how much the overall noise margins vary through the 24hrs. Longer lines, especially if they are overhead, and significantly more so on ADSL, can suffer a lot more noise from dusk to daylight. A very small number of lines may have more noise in the day due to the local environment.
So it's not just so much the turning off to consider, it's when you turn it back on again. If noise levels are high, the sync speed will always be lower because the Target Noise Margin will always be maintained at the point of sync.
The trick with longer ADSL lines was to sync during the day to get the best sync speed. Some lines are awkward in that the SNRM then goes too low at night and the connection drops and a resync is usually at a much slower speed. It then a bit hit and miss to find the best time to resync to get a happy balance between speed and least chance of a dropped connection. Thankfully Fibre isn't usually quite as critical.
However, remember, on Fibre, if DLM does act, it can increase latency or band speed etc and it can take some considerable time (weeks) sometimes before it will reverse such action if the line is otherwise ok. ISPs don't have the ability to do a line reset on Fibre as they do on ADSL.
Generally speaking, the best advise is to leave the modem or combined modem/router switched on unless you are very close to the exchange or Cab for Fibre, when you'll probably get away with switching it off without any consequence if you wish to do so, if your line has no other issues.
