Help in troubleshooting ADSL problems

[thedoc46]

Hi,

Staying around the in-laws at the moment who is running with Sky Broadband. Anyway, signal dies every hr.. Not very familar with ADSL tech settings so if anyone can throw me some advice it would be appreciated.

Logged into the router

Router StatisticsSystem Up Time: 101:52:24

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN PPPoA 4000 5595 0 0 0 0:10:20
LAN 21 0 0 0 0 101:52:24
WLAN 1815900 1141618 0 0 0 101:51:57
ADSL Link Downstream Upstream
Connection Speed 6880 kbps 448 kbps
Line Attenuation 27.0 db 14.5 db
Noise Margin 8.6 db 28.0 db


Modem
ADSL Firmware Version A2pB023o.d20h
Modem Status Up
DownStream Connection Speed 6880
UpStream Connection Speed 448
VPI 0
VCI 38


Exchange is only about 1/2 mile away. Bridgnorth Shropshire...

Does any of those figures seem out of whack ?? I have the basic microfilters they provided on each line.. Are there any reports of these being un-reliable? Should i advise to go with the quality 10quid ones?

 

[turboChiken]

You do have microfilters on all equipment connected to the phone lines including the sky box and all phone extensions?

Also have a look at DMT, available from here http://dmt.mhilfe.de/

There might be a version for your router. If so this will show you more information about your connection like noise margin and errors.

Cheers

Richard

 

[Rroff]

Downstream attenutation is good, upstream ok and upstream noise margin is great... but downstream SNR is running a bit low, even assuming a 6db profile, for the combination of sync speed and attenuation.

If the router is based on the netgear DG834 then you can login using DMT Tool as posted above using 8.07 and selecting special logon.

You might wanna check the ring wire isn't connected for any extensions and that micro filters are properly setup.

http://www.kitz.co.uk/adsl/socket.htm

 

[pennywise]

Router StatisticsSystem Up Time: 101:52:24

I wouldn't think there's anything wrong with the actual broadband... when you say "signal dies", do you mean wireless? If so, that's a completely different problem altogether.

 

[Rroff]

I wouldn't think there's anything wrong with the actual broadband... when you say "signal dies", do you mean wireless? If so, that's a completely different problem altogether.

WAN port uptime shows just over 10 minutes... but that is a good question what is actually dropping... if it is based on the netgrear DG834 then theres some bugs in the latest official firmware that cause connection drops (not the DSL sync) especially with vista/win7.

 

[Rroff]

To give you some idea - taking the approx. line length, downstream attenuation and sync speed into account, depending on the time of day and conditions along the wire/locally - the downstream Noise Margin should be in the range of 11-13db not 8.6. If it is a 6db profile as I suspect you should really be seeing the full 8Mbit or very close on ADSL1 and 13-17Mbit on ADSL2+.


EDIT: Tho 8.6 is quite close to 9db which is the next step up if its using DLM... which still indicates a less than ideal downstream condition.

 

[pennywise]

WAN port uptime shows just over 10 minutes... but that is a good question what is actually dropping... if it is based on the netgrear DG834 then theres some bugs in the latest official firmware that cause connection drops (not the DSL sync) especially with vista/win7.

Ah yes, I see that now. The router "uptime" would appear to be the length of time that the router has been switched on for (as indicated by LAN/WLAN interfaces)? It does appear to be an actual connection problem after all

/little experience with Netgear firmware

 

[Rroff]

I'm only assuming its netgear - it could be a D-Link 27xx as well or a few other routers using the broadcom chipset.

 

[thedoc46]

I'm only assuming its netgear - it could be a D-Link 27xx as well or a few other routers using the broadcom chipset.

Thanks, it's a Sagem router with Sky branding all over it.. Dark Grey in colour.

Can you give me more info on these profiles you mention? 6db Profile or the next step up 9db profile? Is there some way of finding out what profile i should be on?

Just tested via speedtest.net and it's not great at the moment, about 1.2mb down and 300k up with a latency ping of 125ms... Earlier the latency was around 75ms BUT i guess it is that time of day when everyone gets home.

 

[Rroff]

Ah they usually give people the Netgear DG834GT - the sagem uses a similiar chipset but I dunno if its as good as the netgear for connection quality.

I'm not overly familiar with the line management on sky (DLM) - I think it trains for the first 20 days then sets a profile - rather than BT's system which continously changes the profile...

To generalise the DLM system when your connection is first setup uses a target SNR of 6db and will try to sync the line as close to this as possible - if the line then drops more than a certain number of times in an hour, it changes the SNR target up in 3db steps until it hits 15... the higher the SNR target the lower the sync speed will be but the more stable the connection should be.

It might be the DLM system is stuck (which happens all to frequently) and not compensating for the connection drops in which case a DLM reset would be needed - unfortunatly both Sky and BT hate doing this for some reason

EDIT: I'm assuming they are using the Sky IPStream product and not the LLU connection which doesn't use (rambo) DLM.

 

[turboChiken]

Rroff is correct about the target SNR. I have fought Plusnet/BT many times to try to get the SNR reset back to 6db on my line. Worked fine for 18 months then BT decide there are too many errors and increase it to 15 to make my, to me, stable line.....stable. Won't reset it.

Cheers

Richard

 

[Rroff]

If you have a router that works with DMT tool you may be able to over-ride the SNR target - tho with most firmwares this isn't saved so every time the router is restarted you'd have to re-enter it.