Easiest way to check for line drops?

chazzo
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Joined: Sun Jun 21, 2015 9:53 pm

Easiest way to check for line drops?

Post by chazzo » Wed Jun 24, 2015 9:26 am

7800N experts: Is there an easier way to check for line drops and re-syncs than poking around in the system log?

I'm delighted with my second-hand 7800N, but I do find the web interface a bit unintuitive, so apologies if I've missed anything. All the routers I've previously used (2-Wire HGV2700 and various Home Hubs and Voyagers) have displayed either the number of drops since the last reboot, or the time since the last sync.

I notice that older versions of the firmware had an email alert option, which I guess would have been useful for this. But I'm running 1.06h.dt2, which seems to have dropped the notification option. Looking through log files is something I could do without. Can you use the telnet interface for this?

Checking with RouterStats Lite, I saw that occasionally both SNRM and sync rate would spike down to zero before resuming their previous values almost instantaneously. Does anyone else recognise this behaviour, and do you know whether the exchange counts this as a re-sync? In my limited experience with other routers it's unusual to see exactly the same speed after a re-sync. (Running RouterStats permanently seems like overkill, especially since this is a Mac so I have to run it in a virtual machine.)

This is on a long BT line (about 51 dB downstream, though the 7800N reports 60 dB) and my sync speed with the 7800N has been fantastic: around 5600 kbps as standard and over 7000 when I took the SNRM down to zero as an experiment. To start with I saw an immediate boost in download speed to over 4500, which is amazing. However, a couple of thunderstorms seem to have knocked my IP profile back to 2000, though I've been synced at 5696 for a couple of days. I hope it will recover.

Any advice on this would be welcome, especially what will happen if the exchange decides to reduce my target SNRM from the current 15 dB. I have it tweaked to 6 dB at the moment.

Thanks all

Charles

Tomken
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Location: Co Durham

Re: Easiest way to check for line drops?

Post by Tomken » Wed Jun 24, 2015 11:44 am

I'm surprised BT's DLM is letting you run on a tweaked SNRM as it tends to override any tweaks.

I've noticed that the 7800N tends to report a higher Downstream Attenuation than other routers, possibly because of the chipset, but it could also be because a fault has developed on your line.

A difference of 9dB on the Attenuation is a lot - I only get a variance of a max of 4, so give it about a week for the DLM to sort out your SNRM then ask BT to check your line as bad joints, high resistance can increase the Attenuation.

15dB SNRM seems quite a high profile or did the DLM put you onto this following the storms ?

chazzo
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Joined: Sun Jun 21, 2015 9:53 pm

Re: Easiest way to check for line drops?

Post by chazzo » Wed Jun 24, 2015 1:51 pm

Thanks Tomken.
Tomken wrote:15dB SNRM seems quite a high profile or did the DLM put you onto this following the storms ?
I think that was a combination of the storms and trying to get the 7800N set up, which involved a lot of re-syncs. I've been on 6, 12 and 15 at various points. Sometimes the DLM has been quite responsive, while at other times it's been stuck for many months.

I could never seem to get to 9 dB, which would have been ideal with my HH3 since the SNRM often dropped by 6–7 dB in the evenings. The 7800N seems much more stable in this respect, though maybe the winter will show differently.
Tomken wrote:I'm surprised BT's DLM is letting you run on a tweaked SNRM as it tends to override any tweaks.
I've heard several people saying the same thing, but AFAIK the tweak was OK for the whole of last week (I was away), and now for the last 48 hours. I was gobsmacked when I first got the 7800N to sync at high (tweaked) speed and immediately got a faster IP profile to match. That was stable for several days. I kept testing the download speed because I couldn't believe it.

This is a small rural exchange with only BT equipment. Last time I checked, the DSLAMs were Texas Instruments, if that makes any difference. I get confused between the various flavours of ADSL, but this is "up to 8 meg" so I assume it can't be ADSL2+.
Tomken wrote:I've noticed that the 7800N tends to report a higher Downstream Attenuation than other routers, possibly because of the chipset, but it could also be because a fault has developed on your line.
Thanks, though I'm pretty sure I checked on the HH3 before swapping over. It would be a big coincidence if the line went bad within a day or two of changing router. And the 7800N is holding sync at least 1 Mbit higher than I've ever seen before, even with the 2-Wire, which people say is good on long lines.
Tomken wrote:A difference of 9dB on the Attenuation is a lot - I only get a variance of a max of 4, so give it about a week for the DLM to sort out your SNRM then ask BT to check your line as bad joints, high resistance can increase the Attenuation.
Good idea. I believe the attenuation has crept up by 1 dB or so over the last few years, but in the short term it's scarcely varied by 0.1 dB, so perhaps there really is something wrong this time. The BT wires are ancient and the whole village seems to have internet problems, though I suspect most of those are down to dodgy house wiring, WiFi failures and all the other usual suspects.

Tomken
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Location: Co Durham

Re: Easiest way to check for line drops?

Post by Tomken » Wed Jun 24, 2015 10:58 pm

So what was giving you the 51dB Downstream Attenuation ?

Trying to get BT to renew lines to a small "captive audience" community may turn out to be hard work, but I suppose if enough people complain they will eventually have to do something ?

A couple of years back I had a new line from the pole to my home and that seems to have perked up my sync speed using an ISP supplied router.

The speed has dropped off some when I have my 7800N hooked up, although I've had it since July 2011 so it's starting to get a bit long in the tooth now.

billion_fan linked a new firmware for another member which I've downloaded but haven't had time to install yet with having multiple problems on both laptops - but have set aside some time this Friday for that and see if it will rejuvenate it.

I think BT are using a HH5 now so I'd push them for an upgrade to give you a spare new router.

chazzo
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Joined: Sun Jun 21, 2015 9:53 pm

Re: Easiest way to check for line drops?

Post by chazzo » Thu Jun 25, 2015 8:25 am

Tomken wrote:So what was giving you the 51dB Downstream Attenuation ?
Not sure I understand. 49–51 dB is the range that other routers have reported over many years. I think it started at 49 and has now crept up to 51. It's only the Billion that says 60 dB. Could it be measuring at a different frequency, i.e. not 300 Hz?
Tomken wrote:Trying to get BT to renew lines to a small "captive audience" community may turn out to be hard work, but I suppose if enough people complain they will eventually have to do something ?

A couple of years back I had a new line from the pole to my home and that seems to have perked up my sync speed using an ISP supplied router.
Easier to move house, I reckon. Unless a pole actually falls down. There are two poles that serve only this house, so yes, we must be 100 times more expensive to service than when we lived in a terraced house in a city.

Flurry of excitement last year when Openreach said fibre was "coming soon". It took ages, but I saw the fibre go into the trench, and eventually we got to "accepting orders". But BT could not actually sell us Infinity, and eventually I worked out why: the fibre is for the wind farm down the road, and we don't have the second cabinet needed for FTTC. Now our Openreach status is back to "thinking about it".
Tomken wrote:I think BT are using a HH5 now so I'd push them for an upgrade to give you a spare new router.
Hm. I bought one on eBay when I thought fibre was coming, and found I couldn't get it to show any line stats at all. Every freebie they give me ends up extending my contract, and I'd like to move -- it seems that SSE are currently offering a deal that would actually be cheap. I might be wrong about that, though, and here in bundled-land it would definitely be a first :-)

Tomken
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Location: Co Durham

Re: Easiest way to check for line drops?

Post by Tomken » Thu Jun 25, 2015 9:44 pm

billion_fan may be able to tell you why the 7800N is giving the Atten. as 60.

Having some competition in the area may help to spur BT on but as SSE's broadband will be coming down the same lines, the cost may be the only advantage if they can offer the same speed - but I would expect your SNRM to be better with them.

chazzo
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Joined: Sun Jun 21, 2015 9:53 pm

Re: Easiest way to check for line drops?

Post by chazzo » Thu Jun 25, 2015 10:01 pm

Thanks Tomken. I don't understand this unbundling thing. Several other providers offer internet access here, but they are scarcely cheaper than BT because as I understand it they have to pass on BT's standard line rental charge. The SSE deal seemed different and very cheap, but since I never got to actually sign up, there may be some "gotcha" I haven't figured out.

I don't think any other provider could offer less bandwidth than BT! Their estimate is 1.5 Mbps, even though I do get 2—3 Mbps normally and the Billion has shown that it can do an actual download speed of 4.7.

Do you mean that SSE would put me on a lower target margin than 15 dB, or that other providers don't use BT-style DLM? The latter would be good. Although the BT target does fall in time, the DLM approach to thunderstorms seems a bit useless to me. The line is very clean for 99 percent of the time — it's just that every time I hear thunder (and this is East Anglia), the connection is sure to drop several times.

Tomken
Posts: 467
Joined: Tue Jul 26, 2011 10:31 am
Location: Co Durham

Re: Easiest way to check for line drops?

Post by Tomken » Thu Jun 25, 2015 11:34 pm

LLU - http://www.broadbandchoices.co.uk/ask-o ... -broadband

I'm with TalkTalk on a LLU exchange and they are cheaper than BT and I probably get a better speed than BT would have given me on ADSL.

SSE may have some promotional deals if they are new to the exchange, so providing you are free to move, it would be worth checking them out - but I'd take with a pinch of salt if they say you can get x speeds with them as that won't be known until you connect up to them.

They would have their own DLM which could start you off on a 12dB profile as TalkTalk do and providing the connection remains stable and given your 50ish Atten. that should take you down to a 6dB profile after about a week or so, as I am on with TT with a similar Atten.

chazzo
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Joined: Sun Jun 21, 2015 9:53 pm

Re: Easiest way to check for line drops?

Post by chazzo » Fri Jun 26, 2015 8:31 am

Thanks. My BT contract expires in November so I'll see what's available then.

This morning, after just less than 4 days at 5696 kbps without a re-sync, I seem to be back on a 5000 profile, with a measured download speed of 4700. I'm just amazed. Thank you Billion.

Tomken
Posts: 467
Joined: Tue Jul 26, 2011 10:31 am
Location: Co Durham

Re: Easiest way to check for line drops?

Post by Tomken » Fri Jun 26, 2015 3:41 pm

While this site is a little bit dated now http://www.kitz.co.uk/adsl/max_speed_calc.php entering 50 into the Atten. box gives something near your speed, whereas 60 knocks it way down to the 2 - 3 meg you were getting.

BT have their own speed checker but as I don't have a BT phone number, I don't know if it still analyses your line. http://diagnostics.bt.com/login/?workflow=Speed

I tend to use TalkTalk's own speed checker but you can also use http://www.speedtest.net to compare with BT's.

It's best to run that speedtest.net a couple of times as the first one could be a little out.

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