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[Mark07]

Morning all,

Looking to move my parents' line over to BT, but I noticed one of the "features" of the new hub is that it reboots if it detects an issue with the line / network etc

Does anyone know how this would effect DLM? Depending on how often it'll do this and for what faults, could this cause DLM to take some kind of action on the line?

Cheers
Mark

[digitalnemesis]

Yes if exceeds BT's MTBE threshold.

[kitz]

>>  one of the "features" of the new hub is that it reboots if it detects an issue with the line / network etc

Where does it say that it does that?   Ive tried looking and theres loads of reviews.  But all sites appear to base how good a modem is purely on wifi signal.

[Mark07]

Hi guys

@kitz - Over on this page - http://home.bt.com/tech-gadgets/internet/six-reasons-the-bt-smart-hub-is-so-smart-11364071641242

Smart Scan
Unique to BT, Smart Scan technology ensures the Smart Hub functions at its best by scanning for performance issues. If it detects a problem it reboots itself at a convenient time, such as at night.

[roswellgrey]

{joke on}
Sounds like the firmware is full of memory leaks to me, and it reboots itself to clear up the heap 
{joke off}

[gt94sss2]

According to the table on http://www.productsandservices.bt.com/products/smart-hub all BT Home Hubs from v3 have had 'Smart Scan' - I suspect it just means it will reboot while upgrading the firmware automatically..

[Mark07]

Haha I hope it's not to "solve" memory leaks!

Not sure it's for firmware updates, as it states it's if it detects "problems" which i took to mean line problems, but then randomly rebooting isn't going to help surely!

[ejs]

Of course it would be better if the firmware were completely perfect and 100% bug free, but in the real world, the automatic reboot sounds better than leaving the hub in a state where the performance of the Internet connection will be poor until someone manually reboots it.

It wouldn't be the MTBE threshold, that's for Errored Seconds, there are separate MTBR thresholds for re-trains.

[Mark07]

Of course it would be better if the firmware were completely perfect and 100% bug free, but in the real world, the automatic reboot sounds better than leaving the hub in a state where the performance of the Internet connection will be poor until someone manually reboots it.

It wouldn't be the MTBE threshold, that's for Errored Seconds, there are separate MTBR thresholds for re-trains.

In a perfect world yep... I can understand it auto rebooting if those situations, just wondering how that would work, what sort of situations it would see.

IE - Powercut, your hub comes back on first so syncs higher, but as more modems come back online your SNR drops to say 2-3db.

In that situation would the hub reboot to get a higher margin etc Not sure if it's possible for them to code something in so DLM doesn't see it as a "fault drop"...

[roswellgrey]

Now that would be a useful feature - my Billion is a v. quick booter, and that happens every time we get a power cut (we unfortunately get more than the average number of power cuts here ...)

[ejs]

I wouldn't have thought line issues or low SNRM would be what the automatic reboot feature would cover. Router memory or CPU usage might be more applicable.

The DSLAM could set a minimum SNRM parameter, and there's that CoMinMgn setting that could be enabled if the network operator wanted the line to re-train whenever the SNRM dropped below a certain value.

[Mark07]

Very useful, my parents had one a few weeks back and since I don't live there I didn't notice they were running at 2.6db and complaining about slow speeds etc. When I checked there had been 48 million errors since the last retrain 

[ejs]

The feature exists, I didn't say they use it. It also depends what type of errors, FEC errors aren't really errors as such, they just count what the Forward Error Correction has fixed. It would of course also depend on how much time it was since the last retrain.

[kitz]

SNRM parameter, and there's that CoMinMgn setting

That was about the only thing I could think of,  but I was also wondering how it would cope with DLM, especially since there are some lines that may have 3dB target SNRm and perform a daily 1dB swing but still perform satisfactory.

@kitz - Over on this page - http://home.bt.com/tech-gadgets/internet/six-reasons-the-bt-smart-hub-is-so-smart-11364071641242

Thanks that gave me a lead to what they meant.  I dont think its anything to do with DSL, rather with the wifi.

BT Smart Scan technology works in the background, choosing the channel with the least congestion for the best wi-fi performance.

link

BT Smart Hub Press release

• Smart Wireless - Selects the best wifi channel
• Smart Scan - Proactively monitors and improves customers Wifi performance in the background

[Mark07]

Ah thanks for that, so it's likely the wifi interface "restarts" rather than a reboot if the whole unit, that makes more sense.

The bt page makes it sound like it's a full reboot though