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Standard User FarmerGilesUK
(newbie) Thu 24-Mar-11 12:21:12
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Posted Stats and Noise Margin


[link to this post]
 
These stats are from last night after putting v6.1.4.3 firmware on my Speedtouch which resolved the incorrect modulation issue on my line.

How do these stats look?

Link Information

Uptime: 1 day, 1:22:33
Modulation: G.992.1 Annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 1,600
Data Transferred (Sent/Received) [MB/MB]: 34.89 / 327.78
Output Power (Up/Down) [dBm]: 11.5 / 16.5
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 6.0 / 12.0
Vendor ID (Local/Remote): TMMB /
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 32 / 2,020
CRC Errors (Up/Down): 2 / 89
HEC Errors (Up/Down): 2 / 83

Snapshot of SNR

Today I've used the DMT Tool to cause a decrease in target SNR Margin and achieved a sync of 1856kbps.

I guess the acid test will be tonight when the noise on the line increases?

Regards
Standard User BatBoy
(legend) Thu 24-Mar-11 12:26:59
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Re: Posted Stats and Noise Margin


[re: FarmerGilesUK] [link to this post]
 
Looking good, although the power is a bit low.

What did you reduce the SNR Margin to?



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Standard User FarmerGilesUK
(newbie) Thu 24-Mar-11 12:42:40
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Re: Posted Stats and Noise Margin


[re: BatBoy] [link to this post]
 
Just a couple of clicks on the scale. Currently SNR Margin is 10.5dB. Just seen a big spike down to 7.5dB at 12:34 though.


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Standard User BatBoy
(legend) Thu 24-Mar-11 12:46:29
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Re: Posted Stats and Noise Margin


[re: FarmerGilesUK] [link to this post]
 
Something switched on or off? 6dB is probably the lowest



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Standard User FarmerGilesUK
(newbie) Thu 24-Mar-11 12:48:18
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Re: Posted Stats and Noise Margin


[re: BatBoy] [link to this post]
 
Just about the time I was switching HiFi/DAB radio on so quite possibly. tx
Standard User BatBoy
(legend) Thu 24-Mar-11 13:06:32
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Re: Posted Stats and Noise Margin


[re: FarmerGilesUK] [link to this post]
 
Ah ok.

Sorry I wasn't too clear - 6dB is probably the lowest standard Target margin you can set to achieve the best speed without too many disconnections.



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Standard User FarmerGilesUK
(newbie) Thu 24-Mar-11 13:22:18
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Re: Posted Stats and Noise Margin


[re: BatBoy] [link to this post]
 
BTW raised my target SNR from 6-9-12db during the recent 10 day training period. What I don't know is whether this was due to too many errors or multiple resyncs. I was monitoring the link during that period and didn't see multiple resyncs or millions of errors, so none the wiser there really, actually the stats looked quite good. Trouble is I gather the link will have to be *very* stable for quite a lengthy period before DLM will drop the target SNR back down again without manual intervention, hence using DMT tool. If I can get some data that suggests that the link will survive a drop in target SNR then I'll badger my ISP to move it down again.

Does this make sense?
Standard User BatBoy
(legend) Thu 24-Mar-11 13:25:18
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Re: Posted Stats and Noise Margin


[re: FarmerGilesUK] [link to this post]
 
Ah yes, BT's profiling nightmare. Be aware if you lower the margin too much, BT will put you on a banded profile from which you may never recover.



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Standard User FarmerGilesUK
(newbie) Thu 24-Mar-11 13:37:55
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Re: Posted Stats and Noise Margin


[re: BatBoy] [link to this post]
 
I'm only going down a small amount at a time and will monitor performance to see if errors/instability start to appear. I'm *hoping* that a combination of past line faults, an exchange fault and crashy router were responsible for all my problems in the past.

As I think I said in my previous posts, my neighbour gets a very good link (for a not/slow spot) and up until May last year my sync was 2048 and bRAS 1750 - I managed a throughput of 1600ish according to the speed tests, which I was quite happy with. Then the line problems started...

I have a contact at BT (a customer services manager), who has promised to put his best BB engineer on it if I log another fault with my ISP (if problems continue).

Regards
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