Your help needed

[Rik]

We are often asked what speed someone might expect from their line. The answers we give are based upon experience, things we've read on the 'net etc. Different people will give different answers depending on situations they've encountered.

So, I thought it would be useful to collect some data on the subject, and see if we can generate a more reliable predictor, based on as many people's data as possible.

What I would like from you, please, is your d/s attenuation, sync speed and noise margin. If you have had the margin raised, it would be helpful if you could say so.

My figures are:

56db - 3264k - 9db (raised at my request).

Thanks.

[DorsetBoy]

 

Righto Rik, something I see people saying is that the downstream SNR should be 6db or there has been a problem,this is not so,the targert is decided by the exchange equipment during the training period,the target being 6-15 db with a defailt of 6db.

My line hs always been @ 9.5-10.5db.

Now there used to be a chart for workng out the figures but can I find it?

Never mind ourn friend Kitza has saved us all the trouble

Take a look at this.............  http://212.23.23.177/calc.htm and this ........

http://www.internode.on.net/images/copyright/internode-adsl2-distance.jpg

and this .... http://212.23.23.177/ADSL/default.aspx 

Stick in your stats and it's done for you

[Rik]

Those are Saffy's calculators, aren't they. Not surprisingly, they tell me that 3264 is what I can get from my line.

I thought it would be useful to collect some real data, instead of relying on the calculators, then see how that matches. Best of both worlds.

[DorsetBoy]

OK here  are my stats.........

Modulation:   G.992.1 Annex A

Bandwidth (Up/Down) [kbps/kbps]:   448 / 8,128

Data Transferred (Sent/Received) [KB/KB]:   0.00 / 2.00

Output Power (Up/Down) [dBm]:   11.5 / 19.5

Line Attenuation (Up/Down) [dB]:   13.5 / 25.0

SN Margin (Up/Down) [dB]:   21.0 / 10.0

The calculator gives..........

Current Line Sync (connection) speed in Kilo bits per second (Kbps) 8128

Downstream Line Attenuation (dB)25

Noise Margin, sometimes referred to as Signal to Noise Ratio (SNR)10

If you do not know how to obtain your line stats from your ADSL modem or router then visit Kitz's website which shows how to get these values for lots of kit.

 
We estimate that if using a rate adaptive up to 8Mbps service your maximum line speed will be:8128Kbps 

If you are on a Max product, that uses the IP Profile system (sometimes called BRAS Data Rate) if you maintain the above line speed for 3 days or more your IP Profile would be set to: 7.15Mbps

If your service provider uses ADSL2+ we estimate you may manage line speeds of:19097Kbps
With ADSL2+ the maximum IP throughput is likely to be around:16900Kbps

[Rik]

You're making me jealous again, Dorset, especially for the ADSL2+ figures, they barely differ for me.

[DorsetBoy]

You're making me jealous again, Dorset, especially for the ADSL2+ figures, they barely differ for me.

There are 2 bungalows for sale just up the road and there lines are shorter than mine

[Ray]

Here are mine Rik: -

ADSL Link                 Downstream     Upstream
Connection Speed    7616 kbps       448 kbps
Line Attenuation       29 db                9 db
Noise Margin                 10 db                14 db

My IP profile is 6500kbps

[Rik]

Thanks, Ray.

[Inactive]

No idea how to get the figures from the router that I am using, a Zyxel P-660 OHW, sorry.

It was a doddle on my old BT Voyager, however the Zyxel far outperforms the BT. one.

[Lance]

My line hs always been @ 9.5-10.5db.

The reason for this, DB, is because it doesn't need to fall to 6db in order to get increased sync. You already have the maximum sync!

[Rik]

No idea how to get the figures from the router that I am using, a Zyxel P-660 OHW, sorry.

http://192.168.1.1

> Diagnostic
> DSL Line

Up and downstream SNR Margins available

Default username = admin
Password = 1234

According to Kitz. You can get the sync speed from a BT test, if the modem isn't reporting it.

[Inactive]

OK found that it reads;

Noise Margin up  22db
Output Power downstream 12db
Attenuation upstream  5db

Noise Margin Down 17db
Output Power upstream 15db
Attenuation Downstream 9db


None of that means anything to me.. 

[DorsetBoy]

OK found that it reads;

Noise Margin up  22db
Output Power downstream 12db
Attenuation upstream  5db

Noise Margin Down 17db
Output Power upstream 15db
Attenuation Downstream 9db


None of that means anything to me.. 

That means you are @700 metres from the exchange.....what synch speed do you have?
It's on the first page of the Zyxell interface.

[MoHux]

Router DLink DSL-524T.

ADSL Status
 
ADSL status shows the ADSL physical layer status.
 
ADSL Firmware Version: 6.00.01.00 - 6.00.01.00 - 6.00.04.00 Annex A - 01.07.2b - 0.54 
ADSL Software Version: V3.00B01T02.UK-A.20060621
Line State Connected
Modulation ADSL_G.dmt
Annex Mode Annex A 
Max Tx Power -38 dBm/Hz
 
Item           Downstream Upstream Unit
SNR Margin        8               24 dB
Line Attenuation 20             14 dB
Data Rate         7616          448 kbps

My Data Rate always used to be 8128 (540mtrs fm Xchnge) until Easter.  Then it dropped several times when I was doing clean installs of XP and Vista, and Interleaving was put on.  Been at above level for some time now, I can't get it to go back to 8128.

[Rik]

You would need to get interleaving turned off to get the higher sync speed, Mo.

[B52]

Modem Status
Connection Status  Connected
Us Rate (Kbps) 448
Ds Rate (Kbps) 4640
US Margin 24
DS Margin 15
Modulation MMODE
LOS Errors 0
DS Line Attenuation 51
US Line Attenuation 57
Path Mode Interleaved

 
DSL Statistics
Near End F4 Loop Back Count  0
Near End F5 Loop Back Count 0


Edimax Wireless

[MoHux]

You would need to get interleaving turned off to get the higher sync speed, Mo.

Yes, that's what I thought Rik.  My router doesn't record if interleaving is on actually, but my pings went from 15/18 av' to the stock intlvng level 20/26, and have stayed there.
Since easter I have been sperimentin with RWins/MTUs, and trying to get the best out of both O/Ss generally.  Plus getting drivers/updates, all requiring re-boots.
I have delayed asking for interleaving to be turned off until I stopped buttering about!! 

 

[Rik]

Nothing you do at the software level, Mo, should affect your line, ie anything you do in XP will only affect the computer. Unless you disconnect or re-boot the router, you shouldn't be seeing any loss of sync.

[Rik]

DS Margin 15

It looks like your line has had some noise problems and the target noise margin has been set to 15db as a result. If your line is now stable, it might be worth asking for that to be reduced again.

[Inactive]

That means you are @700 metres from the exchange.....what synch speed do you have?
It's on the first page of the Zyxell interface.

Read, it should be on the first page, it isn't.

Less than 700 metres as the crow flies, about 100 yards, same road 7 bungalows away .

[Rik]

Given your noise margin and attenuation, I'd take a bet it's 8128. Why do I feel deprived. 

[RobMc]

Well ok here goes....

Upstream Rate (Kbps) 448
Downstream Rate (Kbps) 8128
US Margin 21
DS Margin 7
Modulation MMODE
LOS Errors 0
DS Line Attenuation 47
US Line Attenuation 51
Path Mode Interleaved

Using a Dlink DSL-G604T and I'm approx 0.63 miles from the exchange as the crow flies.

Rob.

[Inactive]

Given your noise margin and attenuation, I'd take a bet it's 8128. Why do I feel deprived. 

It was on my old BT Router Rik, so I guess it still is.

Sorry.. 

[Rik]

It's OK, think what I have to look forward to if we ever get around to moving! 

[Inactive]

It's OK, think what I have to look forward to if we ever get around to moving! 

True, I never looked at it in that light.. 

[MoHux]

Nothing you do at the software level, Mo, should affect your line, ie anything you do in XP will only affect the computer. Unless you disconnect or re-boot the router, you shouldn't be seeing any loss of sync.

That's the theory Rik ...... but I wondered if someone at IDNet might have seen all the re-boots, and tried to help??

Another thing I have wondered about recently is this;  Vista apparently insists on resetting the RWin and MTU dynamically, in a way BT is also resetting things dynamically, so when one changes something, the other reacts, and you get a see-saw effect between them!   Twisted logic??  Dunno ...... 

[Rik]

Hi Mo

It should be impossible for BT or IDNet to see a re-boot of anything your side of the router, unless it causes the line to drop, and that shouldn't happen. I emphasise shouldn't...

RWIN/MTU settings should only affect traffic throughput. Although you have to re-boot the router to change its MTU setting, anything within Windows shouldn't affect the line.

You could always ask support if they can check whether you are showing a number of re-syncs.

[drummer]

D-link DSL-G604T

Upstream Rate   (Kbps)   448
Downstream Rate (Kbps)   7616
US Margin      23
DS Margin      6
Modulation      MMODE
LOS Errors      0
DS Line Attenuation   28
US Line Attenuation   32
Path Mode      Interleaved (Grr)

Profile 6500
789 meters from exchange

My sync was always 8128 before interleaving was switched on and I don't pretend to understand those figures as the only SNR I have any experience with is in the recording studio.

Coincidence maybe, but a quick glance appears to show those with D-link routers have interleaving on.  I know Miriam doesn't like D-link and I was wondering if some brands are more prone to LOS errors than others.

[Rik]

Thanks for that, Drummer. You can add a Netgear to those with interleaving on, but it's got a lot to do with my lousy line, I've never been in a position to try it on a good line. It's certainly true that some routers seem better at holding a line than others. The problem seems to be that, since Max, it's no longer possible to say that brand A is better than brand B. Now, the best results appear to come from matching the router chipset to that of the DSLAM you are connected to.

Noise margin is based on the same principle of signal-to-noise ratio that you are used to. The difference is that the margin is the amount of headroom the signal has over the point at which the router could not distinguish the signal from the background noise. This makes for a simple figure, where 0 is bad news (though, in practice, I find the Netgear holds the line down to -2db). Doing it that way does away with the need to know what ratio would be acceptable.

[drummer]

Noise margin is based on the same principle of signal-to-noise ratio that you are used to. The difference is that the margin is the amount of headroom the signal has over the point at which the router could not distinguish the signal from the background noise. This makes for a simple figure, where 0 is bad news (though, in practice, I find the Netgear holds the line down to -2db). Doing it that way does away with the need to know what ratio would be acceptable.

Aaaaaah!  *Sound of penny dropping* 

Thanks for that Rik as I've read up on it more times than I care to think and it always goes over my head (having dyscalculia doesn't help  ).

[Rik]

That must make life very hard for you, sorry to hear it.

[drummer]

That must make life very hard for you, sorry to hear it.

My point was that your explanation worked for me, so thanks muchly and have a karma. 

Frick my problem, it's one of those things.  Just that I'm used to knobs, faders, strobing LEDs and a pair of lugholes to obtain optimum SNR and ADSL is, how you say? a challenge.

[Rik]

My point was that your explanation worked for me, so thanks muchly and have a karma. 

Thank you kindly.

Frick my problem, it's one of those things.  Just that I'm used to knobs, faders, strobing LEDs and a pair of lugholes to obtain optimum SNR and ADSL is, how you say? a challenge.

ADSL was put on earth to frustrate and confuse us all - BT is its agent! 

[PhilFlyer]

but it's got a lot to do with my lousy line

Sorry Rik but THATS not a lousy line.

THIS is a lousy line 

Uptime:   0 days, 7:52:11
Modulation:   G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:   448 / 224
Data Transferred (Sent/Received) [MB/MB]:   2.39 / 1.81
Output Power (Up/Down) [dBm]:   12.0 / 14.0
Line Attenuation (Up/Down) [dB]:   31.5 / 63.5
SN Margin (Up/Down) [dB]:   10.0 / 6.5
Vendor ID (Local/Remote):   TMMB / P
Loss of Framing (Local/Remote):   0 / 0
Loss of Signal (Local/Remote):   13 / 0
Loss of Power (Local/Remote):   0 / 0
Loss of Link (Remote):   0
Error Seconds (Local/Remote):   425 / 0
FEC Errors (Up/Down):   0 / 256,101
CRC Errors (Up/Down):   0 / 10,544
HEC Errors (Up/Down):   0 / 6,442

It normally synchs at around 1000k with a noise margin between 7 and 3. It has even managed to get on the 1mb profile for short periods but then large noise spikes bringing the synch rate down to around 500 - 700 at regular intervals. Today is the worst its been. All actions regarding wiring and master socket as recommended here and Thinkbroadband have been carried out.

Phil

[Rik]

That is a bad line, Phil, my sympathies and this somewhat worthless crown to wear.

I take it the line has been tested?

[PhilFlyer]

Hi Rik

I have spoken to IDNET a few times about this and they and BT have done tests - at one time BT said they had found and fixed a fault but nothing really changed.

IDNET have offered to have a BT engineer call but are concerned that they might declare the line out of limits for broadband and withdraw it. This would be  disaster so I don't really know what to do. ( I believe my line has already been marked unsuitable for a fixed 512k connection - even though I can normally sync at 1000k and a neighbour who is further than me from the exchange and whose lines go past my house has a perfectly working 512k connection !)

I have monitored my noise margin using Routerstats and there are huge spikes of noise during the day, usually starting fairly promptly at 6.30 am after a "quiet" night

The connection usually picks up after a few days and apparantly the current weather can have an adverse effect on overhead lines.

Phil

[Rik]

It's difficult to know what to advise, Phil. I think support are quite right to be wary of BT marking the line 'unfit'. Without a universal service obligation for ADSL, they can do that without you having any right of appeal. Are there any LLU operators in your exchange? That might be the only way to improve things though, tbh, I have a feeling the line is always going to be an issue unless BT replace it, and they aren't keen to do that sort of work.

If you notice any effect on the voice side because of wet weather, it would be worth reporting it via 151.

[PhilFlyer]

I don't know who else is in my exchange but as you say, it will be the same old poor line with presumably the same result. Can BT really just cut off BB with no appeal or do they just refuse to service it ? The voice side of my line is fine at the moment but yes, in the past I have complained at the slightest crackle in case they find anything that might improve the BB side.


Phil

[Rik]

Just possibly, Phil, you might get an improvement from LLU - but it's by no means certain. Unfortunately, if it didn't work out well and you decided to move back to BT, there's every chance BT would refuse to provision ADSL. BT have no obligation whatsoever to provide a broadband service, so they can withdraw it at any time without you having a right of appeal.

[PhilFlyer]

Thanks Rik - I think I will just wait for now and see what happens. Just after my last post I noticed my noise margin had gone up to 10db so a reboot has put me up to 640k.  This is how up and down it is all the time.

[Rik]

Unfortunately, Phil, in your situation all the normal advice is of no help. Other than going to something like a satellite solution, you don't really have a lot of options. Even if you paid BT to run new cables (and it would probably be painfully expensive given the length of line you are likely to have), there's little guarantee that it would improve your ADSL connection and, because there is no USO, there's no redress for you if it didn't. Is moving an option?

Afterthought: Take a look at this thread. It might just help you to try that router...

[PhilFlyer]

Thanks Rik

The BT 2700 router looks interesting but can't find it anywhere yet.

Phil

[Rik]

It seems to be an eBay item, as far as I can tell.

[Inactive]

It seems to be an eBay item, as far as I can tell.

It is Rik, I havn't seen them anywhere else, they are commercial products made for BT industrial installs, as far as I can tell.

[Rik]

Thanks for the confirmation. Perhaps we should buy a bunch and resell them here?

[PhilFlyer]

Thanks for the confirmation. Perhaps we should buy a bunch and resell them here?

Let me know if you do because I can't find one anywhere including Ebay

Phil

[Inactive]

Plenty on eBay, put in 2Wire to search engine on networking.

Make sure it is the 2700 HGV model, not the 1800 model, and also that it is unlocked.

BTW, there is no guarantee that this will improve things for you, we are only going on feedback on here.

[PhilFlyer]

Inactive - found it, thanks for that - not a fortune at £40-50 but I will have to research this a bit more before I add yet another router to the collection of 3 that I have already.

Phil

[Rik]

You could always shift some of your old stock on eBay is this one does the job for you, though I always keep at least one spare myself.

[Den]

Hi Phil, The guy I bought my BT 2700HGV Hub off is selling on ebay at £41.99 plus postage. I found this seller to be very helpfull,responsive and quick. The router is superb. I live about two mile from my exchange and am now running without problems. 

[PhilFlyer]

Hi Den

Can you give any information regarding the difference between your 2700 and what you had previously especially if you can compare with a Speedtouch 585?

An ebay seller (ydrol) is offering the 2700 at £41.99 with a money back guarantee (less postage)  if it does not improve synch rate. Seems a good deal. Is this the same seller that you bought from ?

By the way would you believe that my connection has now shot back up to 1152k at 5.5db. Perhaps its because the rain has eased off!

Phil

[Den]

Hi Phil, Yes thats the guy, very good service as well (I`m not on commision). He is, I suppose offering his returns policy after the positive feedback from everbody that has bought these off him, I know I emailed him after he inquired how much improvment it made and thanked him my self. For a comparison on how this router helped, look at my plea for help (from all these great guys on this forum) under the heading SPEEDCHECKS. I know that I would not want to use any other router after this.   

[Inactive]

Strange thing is, these 2Wire 2700 HGV Router / Modems were selling for £8.50 a couple of months ago on eBay, obviously they have become more popular due to their  often discussed magic qualities on poor lines.

One seller has now listed some new ones for £30 + £6 postage, quite a bargain in todays climate.

[Den]

Just make sure these are the most recent ones and ar unlocked. All the very cheap ones are either old stock or locked to BT. IDNET is still tops 

[PhilFlyer]

Thanks for all the input everybody. Stats back to what I regard as "normal" today    -  but I will still probably try the 2Wire 2700 as a result of the comments in this forum.

Uptime:   0 days, 14:50:25
Modulation:   G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:   448 / 1,152
Data Transferred (Sent/Received) [MB/MB]:   12.10 / 13.68
Output Power (Up/Down) [dBm]:   12.0 / 16.0
Line Attenuation (Up/Down) [dB]:   31.5 / 63.5
SN Margin (Up/Down) [dB]:   10.0 / 6.5
Vendor ID (Local/Remote):   TMMB / P
Loss of Framing (Local/Remote):   0 / 0
Loss of Signal (Local/Remote):   17 / 0
Loss of Power (Local/Remote):   0 / 0
Loss of Link (Remote):   0
Error Seconds (Local/Remote):   448 / 0
FEC Errors (Up/Down):   0 / 1,967,743
CRC Errors (Up/Down):   0 / 44,032
HEC Errors (Up/Down):   0 / 31,339