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shirley_connon
Aspiring Contributor
2,644 Views
Message 1 of 12

Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Hello,

 

Experiencing regular disconnections (every 2 days or less) / stability issues from internet and slow page loading since 14th May.

SNR Margin downstream and upstream is normally in range of day = 6.5 and night = 5.5 (DB) for last 6 months which is relatively stable.

 

Now getting regular SNR of 3.0 downstream (day and night) and has dropped to 0 at times at evening. SNR at 3 seems to generate lots of HEC errors, slow page loading and issues using VOIP although connection rate seems higher.

 

Seems to be connecting at SNR of 3 for a few days then drops back to 6 SNR again after an disconnect and then repeats again after a few days. Not sure if something is triggering to lower the SNR to 3 thinking it is stable then realising unstable so re-adjusts back to SNR of 6.

 

Modem (Billion) connected to master socket (Openreach MK3)

Quiet line test no noise even when SNR at 0

Resetting modem does not help

Connecting to test socket does not improve SNR

Connecting alternative modem HH4 same SNR

Replaced router cable

 

What i see when connection drops. I can watch the SNR reduce step by step down to 1 or even zero over a 5 or 6 minute period at nights. After a few minutes goes back up to SNR of 3 which is still generally unstable with slow connections to web pages and issues using VOIP for home working etc. Did previously see drops to 3 at night occasionaly when the default SNR was 6 but at 6 as a starting point there seemed enough headroom to keep connection.  

 

Connection information 31st May

 

Model Name

BiPAC 8800NL

Host Name

home.gateway

System Up-Time

12D 17H 30M 35S

Date/Time

Tue May 31 15:56:09 2016 

Software Version

2.32d.dh65

LAN IPv4 Address

XXXXXXXXXXXXX

LAN IPv6 Address

XXXXXXXXXXXXX

MAC Address

XXXXXXXXXXXXX

DSL PHY and Driver Version

A2pv6F039g1.d24m

Wireless Driver Version

6.30.102.7.cpe4.12L08.4

WAN

Line Rate - Upstream (Kbps)

961

Line Rate - Downstream (Kbps)

4348

Default Gateway / IPv4 Address

pppoa0 (DSL) / XXXXXXXXXXXXX

Connection Time

2 Day(s) 13:38:26

Primary DNS Server

213.120.234.70

Secondary DNS Server

213.120.234.50

Default IPv6 Gateway / IPv6 Address

pppoa0 (DSL)

 

 

xDSL

Mode

ADSL_2

Traffic Type

ATM

Status

Up

Link Power State

L0

 
 

Downstream

Upstream

Line Coding (Trellis)

On

On

SNR Margin (dB)

3.3

5.8

Attenuation (dB)

52.5

33.7

Output Power (dBm)

0.0

12.7

Attainable Rate (Kbps)

4808

968

 

Rate (Kbps)

4348

961

 

K (number of bytes in DMT frame)

0

0

R (number of check bytes in RS code word)

0

0

S (RS code word size in DMT frame)

0

0

D (interleaver depth)

32

4

Delay (msec)

8

6

INP (DMT symbol)

1.00

0.50

 

Super Frames

68122430

60833959

Super Frame Errors

209469

1621

RS Words

1600684123

1257012

RS Correctable Errors

25969919

11193

RS Uncorrectable Errors

8808407

0

 

HEC Errors

7849955

2225

OCD Errors

1286

0

LCD Errors

1286

0

Total Cells

4016658719

882218646

Data Cells

177734324

41552369

Bit Errors

467714984

72026

 

Total ES

14971

985

Total SES

3184

0

Total UAS

3479

387

 

 

 

Recent connection information on drop. Note SNR -2

 

xDSL

Mode

ADSL_2

Traffic Type

ATM

Status

Up

Link Power State

L0

 

 

Downstream

Upstream

Line Coding (Trellis)

On

On

SNR Margin (dB)

-0.2

6.1

Attenuation (dB)

52.5

33.6

Output Power (dBm)

0.0

12.6

Attainable Rate (Kbps)

4236

988

 

Rate (Kbps)

4438

964

 

K (number of bytes in DMT frame)

0

0

R (number of check bytes in RS code word)

0

0

S (RS code word size in DMT frame)

0

0

D (interleaver depth)

32

4

Delay (msec)

8

6

INP (DMT symbol)

1.00

0.00

 

Super Frames

2554424

2306513

Super Frame Errors

21770

70

RS Words

23794089

3989406

RS Correctable Errors

703515

138

RS Uncorrectable Errors

685317

0

 

HEC Errors

593296

139

OCD Errors

145

0

LCD Errors

145

0

Total Cells

61934672

13146621

Data Cells

26272362

1122932

Bit Errors

33316580

4589

 

Total ES

6531

35

Total SES

216

0

Total UAS

326

113

 

Any advice

 

Thanks

 

Jon and Shirley

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11 REPLIES 11
imjolly
Distinguished Sage
Distinguished Sage
2,640 Views
Message 2 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

can you check for interference that may be causing the drop in noise margin

 


interference causes

 

 

do you use a phone extension cable to connect hub to MK3

 

 



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shirley_connon
Aspiring Contributor
2,622 Views
Message 3 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Hello,

 

Thank you for the response and advice.

 

The house is basically in shutdown mode during the day apart from my office room which has a monitor and laptop eg not heating, pumps etc Tried disconnecting a dect phone, sky box and any other electrical items for 5 hours this evening but SNR is still showing at around 2.8. No new electical items have been introduced since issues started on the 14th May.

 

I use a RJ11 cable to connect from the hub directly to the data port on the Openreach V3 socket.

The cable has been swapped out and also direct connecton using a filter to master socket also tried.

 

I have a fairly long line straight to the exchange rather than a cabinet hence SNR of 3 is pretty unstable which it seems of to defaulted to most of the time. A SNR of 6db seems to be required to keep the connection stable in my case. Not sure if something has changed at the exchange side to set SNR to 3 as default.

 

 

Thanks

0 Ratings
shirley_connon
Aspiring Contributor
2,605 Views
Message 4 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Hello,

 

I believe DLM can reduce noise margin to 3Db.
It looks to me that the DLM has reduced my line to a 3Db profile which although gives a faster connection speed is generally more unstable on my direct long copper line to the exchange.
Over the last few weeks my current downstream SNR is basically 3DB lower than usual taking into account my usual 1-1.5 db variences between night and day.

 

Can a 6dB profile be set on my line with interleaving still left switched on to help stabalise this ?

 

Of course you are the experts so just adding my thoughts and observations 🙂

 

Many Thanks

 

Jon and Shirley

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imjolly
Distinguished Sage
Distinguished Sage
2,599 Views
Message 5 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

the DLM reduces the noise margin to 3db on what it considers good connections but on a few occasions the new normal noise margin can cause problems  I still think there is interference causing your noise margin to drop to zero but see if mods can reset your noisemargin back to 6db and stabilise your line  mods will post a contact us link here  





contact mods.jpg


After completing the email NOT PM then you join a queue of other customers waiting for mod help. The mods will get back to you in 1/2 working days either by phone or email



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shirley_connon
Aspiring Contributor
2,592 Views
Message 6 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Thank you very much for your help.

 

I will continue to explore potential interference areas and await contact from the mods to see if they can reset my noisemargin back to 6db and stabilise the line.

 

Jon and Shirley

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DavidM
Moderator
Moderator
2,590 Views
Message 7 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Hi @shirley_connon and thanks for posting.

 

I'm sure we can help you with this. Can you drop me over an email with your details? You'll get the contact the modeators link in my profile.

 

Cheers

 

David

shirley_connon
Aspiring Contributor
2,500 Views
Message 8 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Hello,

 

After some changes bny Rowan it seemed the SNR margin became stable at 6db for a while.

However this has now reverted back to a 3db SNR profile again.

Rowan advised that if this solution implemented did not work then a fixed 6db Noise profile would need to be set/requested to Open Reach.

Rowan advised to raise the issue back again through the forum if it reoccured

 

Can you advise the process to reopen or do I need to open another call ?

 

xDSL

Mode

ADSL_2

Traffic Type

ATM

Status

Up

Link Power State

L0

 
 

Downstream

Upstream

Line Coding (Trellis)

On

On

SNR Margin (dB)

3.4

4.8

Attenuation (dB)

52.5

33.9

Output Power (dBm)

0.0

12.7

Attainable Rate (Kbps)

4848

940

 

Rate (Kbps)

4352

924

 
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imjolly
Distinguished Sage
Distinguished Sage
2,497 Views
Message 9 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

mods will post here  



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RobbieMac
Moderator
Moderator
2,494 Views
Message 10 of 12

Re: Performance issues - SNR Margin range Downstream (DB) 3.0 to -0.2 since 14th May

Hi @shirley_connon

 

I've let Ronan know that the SNR has dropped and it's causing stability issues again.  He'll be in touch to let you know what happens next to get it back to 6db and stay there!

 

Cheers,

 

Robbie