My line profile and attenuation - podman's problem

[#1]

I was lead to believe that attenuation could not be changed.
I believe I had my line attentuation fixed to 9db by PN previoulsy and at that time i saw an increase in speed. My attenuation has increased to 14 and my sync speed has decreased as a result.
If Pn can still set attenuation? how do i need to speak to as the person i asked on the phone the last time said nothing could be done.
podman

[#2]

I think you are confused
The attenuation is a physical effect related to line length and quality
You are referring to the default noise margin where the line speed drops as the default noise margin increases

[#3]

hI Oldjim,
I maybe am confused. if there anyway that the downstream noise margin can be set then?

[#4]

If your line is stable then Plusnet can request a retrain/reset but if the errors/disconnections cause a rise again then they will not be able to do it again.
So before doing anything you need to ensure that your line is in a state where it can hold the lower noise margin.
The fact that it increased from 9dB to 15dB indicates that there is a problem and you need to sort that first.
However - as it appears that it has been reduced once that may well result in BT refusing to do it again

[#5]

I have gone through 3 routers since then, different filters and at least one engineer  visit. As long as there has been a dsl signal that works I've never managed to get anything done aboutt he drop in sync. from the early year or so of upto 8mb
so I don't beleiev the issue is my side of the connection as there has been so many changes of equipment and I still have the lower syncs.
podman.

[#6]

Connect your router to the TEST socket within the BT master socket ......... if you have this type of master socket  > link.
If the router loses sync often then it would suggest the problem is between there and the exchange so tell that to PN and they can get  BT Openreach to look into this problem.
If however there are no problems when connected to the TEST socket then that would suggest that there is an issue with your internal phone wiring and/or extensions.
All this depends on the router and micro filters all being in good working order.

Line stats explanation from the KITZ website.

[#7]

HI podman,
Have you had any better results in the test socket?
Jojo

[#8]

I have just requested change to 21cn. In my research I found the calculator on kitz website and the page that estimates your line length. I remember at some point in the past my line length was estimated at actually being about right distance from the exchange (1.77km by road, 1.45 direct) when i put in the line stats from my router.
On checking on kitz site today using the line length calculator it estimates roughly the same but when I use the 21cn speed calculator putting in the current Downstream Attn at 43 my line length is estimated as over 3km.
Could it be that my line has at some point been swapped to a longer one without my knowledge, which would explain why my sync speed has dropped from previous 8128kbps to never really going above 5000kbps, or could it be my line has deteriorated to cause the change.
is there a feasible way to get it swapped back to a shorter line or would I have to own bt first.

[#9]

Just found this in the old archives: The higher sync was not my imagination but the downstream attn appears to have been 😞
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http://community.plus.net/forum/index.php/topic,25505.32.html
   podman
   Posts: 1025
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« Reply #37 on 13/05/2006, 16:02 »
Starts at present are:
DSL Status :   Up    
     DSL Modulation Mode :   GDMT    
     DSL Path Mode :   FAST    
     Downstream Rate :   7552 Kbps    
     Upstream Rate :   448 Kbps    
     Downstream Margin :   5 db    
     Upstream Margin :   25 db    
     Downstream Line Attenuation :   46    
     Upstream Line Attenuation :   24    
     Downstream Transmit Power :   0    
     Upstream Transmit Power :   0
My line speed has stabalised at 7000kbps and Plusnet agree that I'm on the incorrect profile as my downaload speeds are at or bwloew 2mb. I have raised a ticked to get my profile changed so here'e hoping it will happen soon.
There was talk elsewhere on the forums of pl;usnet fixing this problem over a 48hr period from the 9th on obviuosly my account wasn't included.
Looking forward to seeing the difference.
A
---------------------------------
also here so it really is not my imagination  my line used to be so much better.
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   Personal Message (Offline)
« Reply #67 on 25/05/2006, 20:35 »
Here is a list of my line stats (see below) why do these still vary so drastically from my download speeds. I was maxed on 3rd May thuogh I have still to recieve a mail from plusnet telling me of this change, reading earlier post could that be the problem?

Are these results the same as everyone else. Do we really believe BT that it'll all be fixed by the time the bulk upgrade tool is re-introduced on 6th June?
I'm not moaning here just asking what everyone elses stats and spped are.
Cheers
A
DSL Status :   Up    
     DSL Modulation Mode :   GDMT    
     DSL Path Mode :   FAST    
     Downstream Rate :   8000 Kbps    
     Upstream Rate :   448 Kbps    
     Downstream Margin :   3 db    
     Upstream Margin :   23 db    
     Downstream Line Attenuation :   46    
     Upstream Line Attenuation :   24    
     Downstream Transmit Power :   0    
     Upstream Transmit Power :   0

Is there anything i can do to get it back to tip top performace. In the master socket no extensions. Downstream noise margin appears to be the main difference in the stats.
---------------------------------------------
Todays stats for comparison. 21:44. 28th Jan 2011
ADSL
  Type Fast Path
  Status Show Time
   Downstream Upstream
  Data Rate (kbps) 5024 448
  Noise Margin (dB) 12.0 25.0
  Attenuation (dB) 43.2 21.0
  Output power(dbm) 19.4 12.1

[#10]

The downstream noise margin values in your old stats are 3 and 5dB whereas this is 12dB in today's. From this I think your downstream target noise margin has probably been increased by the DLM from 6dB to 12dB (to stabilise the line and reduce error rates).
Each 3dB increase in target noise margin typically reduces sync speeds by 500 to 800kbps. So 6dB's worth is 1000 to 1600kbps which goes a long way towards accounting for the difference in sync speeds between you old stats and the current ones.

[#11]

is there anything i can do to reduce this. i have tried new filters, master sockets, new router, cables etc. is the problem basicslly with the line. no noise on a noise test.
cheers podman

[#12]

Does you router give error information (CRC and HEC) on any of its displays. If those show "high" rates per day (a subjective description) it's an indication of what the DLM might be concerned about.

[#13]

current router belkin share dosn't seam to show crc or hec errors. I have sent a support question to belkin asking for hidden pages etc but not holding my breath. may need to try another router to check. it's also a belkin but hopefully one with more reports.
podman

[#14]

Are these the type of figures you mentioned.
Statistics -- ATM
ATM Interface Statistics
In Octets: 1680528
Out Octets: 188016
In Errors: 0
In Unknown: 0
In Hec Errors: 0
In Invalid Vpi Vci Errors: 0
In Port Not Enable Errors: 0
In PTI Errors: 0
In Idle Cells: 0
In Circuit Type Errors: 0
In OAM RM CRC Errors: 0
In GFC Errors: 0

AAL5 Interface Statistics
In Octets: 1680528
Out Octets: 188016
In Ucast Pkts: 1567
Out Ucast Pkts: 1149
In Errors: 1
Out Errors: 0
In Discards: 0
Out Discards: 0

AAL5 VCC Statistics
CRC Errors: 1
SAR Timeouts: 0
Oversized SDUs: 0
Short Packet Errors: 0
Length Errors: 0
is it possible to request the snr to be test to 6 or 9 before my change to 21cn?

[#15]

Yes, CRC and HEC errors are mentioned amongst those figures, but trivial values. Does your connection still drop? And have you tried connecting to the test socket? I suspect Plusnet would want to do a line test while your router has been plugged into the test socket for 2 or 3 days before considering an SNR reset.