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Guru
897 Views
Message 1 of 19

FECn Errors

After years of flawless 5M service, I've been having trouble with my broadband connection for months now. Had the engineer out who replaced some cabling outside and the master socket. I've replaced everything indoors except the hub (V1). I've tried plugging the hub directly into the master socket rather than keeping it at the end of an extension. Each different confirguration has been given a number of days to bed in, but nothing gets close to the 5M speeds I used to get. I have one phone and the hub connected to the ADSL filter (tried several of those), so it's not a particularly complicated arrangement.

 

I've just looked at the hub and read these stats:

 

Uptime:0 days, 2:35:41
Modulation:G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:448 / 672
Data Transferred (Sent/Received) [MB/MB]:6.54 / 29.50
Output Power (Up/Down) [dBm]:11.5 / 13.0
Line Attenuation (Up/Down) [dB]:27.0 / 46.0
SN Margin (Up/Down) [dB]:20.0 / 9.5
Vendor ID (Local/Remote):TMMB / ALCB
Loss of Framing (Local/Remote):0 / 0
Loss of Signal (Local/Remote):1 / 0
Loss of Power (Local/Remote):0 / 0
Loss of Link (Remote):0
Error Seconds (Local/Remote):25 / 0
FEC Errors (Up/Down):0 / 369,973
CRC Errors (Up/Down):0 / 0
HEC Errors (Up/Down):0 / 0
Line Profile:Interleaved

 

The thing which stands out is the FEC errors. Is this a normal number? It seems a tad high to me.

 

Any thoughts gratefully appreciated.

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18 REPLIES 18
chris6273
Recognised Expert
889 Views
Message 2 of 19

Re: FECn Errors

FEC Errors - Indicate the amount of errors that have been corrected through interleaving. This number shouldn't matter if interleaving is enabled because it means its doing it's job properly.

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IanC
Recognised Expert
872 Views
Message 3 of 19

Re: FECn Errors

 


@guilbo wrote:

After years of flawless 5M service, I've been having trouble with my broadband connection for months now. Had the engineer out who replaced some cabling outside and the master socket. I've replaced everything indoors except the hub (V1). I've tried plugging the hub directly into the master socket rather than keeping it at the end of an extension. Each different confirguration has been given a number of days to bed in, but nothing gets close to the 5M speeds I used to get. I have one phone and the hub connected to the ADSL filter (tried several of those), so it's not a particularly complicated arrangement.

 

I've just looked at the hub and read these stats:

 

 

Uptime:0 days, 2:35:41
Modulation:G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:448 / 672
Data Transferred (Sent/Received) [MB/MB]:6.54 / 29.50
Output Power (Up/Down) [dBm]:11.5 / 13.0
Line Attenuation (Up/Down) [dB]:27.0 / 46.0
SN Margin (Up/Down) [dB]:20.0 / 9.5
Vendor ID (Local/Remote):TMMB / ALCB
Loss of Framing (Local/Remote):0 / 0
Loss of Signal (Local/Remote):1 / 0
Loss of Power (Local/Remote):0 / 0
Loss of Link (Remote):0
Error Seconds (Local/Remote):25 / 0
FEC Errors (Up/Down):0 / 369,973
CRC Errors (Up/Down):0 / 0
HEC Errors (Up/Down):0 / 0
Line Profile:Interleaved

 

 

The thing which stands out is the FEC errors. Is this a normal number? It seems a tad high to me.

 

You're on an interleaved connection - FEC errors are nothing to be concerned about.  The stand-out problem is your SN margin of 20dB, which suggests that you've a fault condition or interference somewhere on your line.


If you pick up a 'phone - preferably a corded one, not wireless - and dial a digit (to get rid of the dialling tone) can you hear any noise/interference ?


Do you have a master socket with a horizontal split ?  If so, remove the faceplate and connect the router to the socket behind it. This isolates your internal wiring from the external BT line to the exchange.

 

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Distinguished Sage
Distinguished Sage
865 Views
Message 4 of 19

Re: FECn Errors


@IanC wrote:

 


@guilbo wrote:

After years of flawless 5M service, I've been having trouble with my broadband connection for months now. Had the engineer out who replaced some cabling outside and the master socket. I've replaced everything indoors except the hub (V1). I've tried plugging the hub directly into the master socket rather than keeping it at the end of an extension. Each different confirguration has been given a number of days to bed in, but nothing gets close to the 5M speeds I used to get. I have one phone and the hub connected to the ADSL filter (tried several of those), so it's not a particularly complicated arrangement.

 

I've just looked at the hub and read these stats:

 

 

Uptime:0 days, 2:35:41
Modulation:G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:448 / 672
Data Transferred (Sent/Received) [MB/MB]:6.54 / 29.50
Output Power (Up/Down) [dBm]:11.5 / 13.0
Line Attenuation (Up/Down) [dB]:27.0 / 46.0
SN Margin (Up/Down) [dB]:20.0 / 9.5
Vendor ID (Local/Remote):TMMB / ALCB
Loss of Framing (Local/Remote):0 / 0
Loss of Signal (Local/Remote):1 / 0
Loss of Power (Local/Remote):0 / 0
Loss of Link (Remote):0
Error Seconds (Local/Remote):25 / 0
FEC Errors (Up/Down):0 / 369,973
CRC Errors (Up/Down):0 / 0
HEC Errors (Up/Down):0 / 0
Line Profile:Interleaved

 

 

The thing which stands out is the FEC errors. Is this a normal number? It seems a tad high to me.

 

You're on an interleaved connection - FEC errors are nothing to be concerned about.  The stand-out problem is your SN margin of 20dB, which suggests that you've a fault condition or interference somewhere on your line.

 
Noise margin is 9.5 not 20 - shown other way round from normal

If you pick up a 'phone - preferably a corded one, not wireless - and dial a digit (to get rid of the dialling tone) can you hear any noise/interference ?


Do you have a master socket with a horizontal split ?  If so, remove the faceplate and connect the router to the socket behind it. This isolates your internal wiring from the external BT line to the exchange.

 


 



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IanC
Recognised Expert
860 Views
Message 5 of 19

Re: FECn Errors

 


@imjolly wrote:
Noise margin is 9.5 not 20 - shown other way round from normal

 Yup - just noticed that 😞  My bad...

 

The rest still stands though - 46dB attenuation should give a much higher sync speed than that 😞

 

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Guru
846 Views
Message 6 of 19

Re: FECn Errors

Thanks for your assistance, folks. I've tried the test socket thing, doesn't make a lot of difference. You've reassured me that I'm not going nuts. Good tip to try a corded phone. Sounded clear as a bell both at the end of the extension and direct from the master. Unfortunately I can't connect to the master socket as a permanent arrangement as it was fitted back in the day when all you could connect to the BT line was the phone they rented you and there was no concept of having to have a power socket anywhere near it, so there isn't.

 

Sorry about the up/down confusion of the stats, it's the way the HH1 presents them.

 

Looks like I may have to get the good people at BT back in.

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Guru
801 Views
Message 7 of 19

Re: FECn Errors

Still struggling with my broadband service, but here's a wierdie which I wonder if any of you boffins out there can explain.

 

Back when my line was running well, the Assured Rate Test would usually give me somewhere around 530-570 on a profile of 600. Ever since the engineer has been, however, I tend to get something like today's test:

 

FAQ



1. Best Effort Test: -provides background information.

 Download speedachieved during the test was - 1610 Kbps
 For your connection, the acceptable range of speeds is 400-2000 Kbps.
 Additional Information:
 Your DSL Connection Rate :5632 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
 IP Profile for your line is - 1750 Kbps

2. Assured Rate Test: -provides background information.

 Download speedachieved during the test was - 1017 Kbps
 For your connection, the acceptable range of speeds is 576-600 Kbps.
 Additional Information:
 Assured Rate IP profile on your line is - 600 Kbps

 

 

Where the assured rate is well above its profile. Is this normal behaviour or just a bit of inconsequential wierdness? Or is this an indication of something a bit more sinister happening behind the scenes? It's strange that this only seemed to start happening when things went wrong.

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IanC
Recognised Expert
771 Views
Message 8 of 19

Re: FECn Errors

 


@guilbo wrote:

[snip

 

 Is this normal behaviour or just a bit of inconsequential wierdness? .


Personally, I'd not worry about it.
Of far more concern is that your IP profile is much too low for your sync speed...
What are your sync speed and profile like 24hrs later ?

 

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Guru
737 Views
Message 9 of 19

Re: FECn Errors

Thanks for the reply. It usually takes a good few hours for it all to fall apart, for reasons still unknown. Now connected to the test socket, just to make sure that the new faceplate the engineer fitted wasn't causing an issue. Actually ran (profile and all) at >4M for a good 6 hours....and then sync fell to about 1800 (in fact the PC was down when the hub chose to reboot itself, so the only thing which could have been having a chat on the line at the time was the Vision box which was on standby). Profile was 1250 about 6 hours ago, but has dropped to 1000 for no reason at all. Last speedtest about half an hour ago got me 890 throughput. The Internet light also went out this afternoon (but broadband stayed on) which forced me to do another reboot, which was 7 3/4 hours ago. There is something really wrong somewhere as attenuation and SNR seem to imply that it shouldn't be running like this. Thanks again for your assistance, Ian.

 

Uptime:0 days, 7:48:08
Modulation:G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:448 / 2,144
Data Transferred (Sent/Received) [MB/MB]:12.18 / 143.96
Output Power (Up/Down) [dBm]:11.5 / 17.5
Line Attenuation (Up/Down) [dB]:27.0 / 46.0
SN Margin (Up/Down) [dB]:19.0 / 10.0
Vendor ID (Local/Remote):TMMB / ALCB
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):0 / 486,576
CRC Errors (Up/Down):0 / 1
HEC Errors (Up/Down):0 / 0
Line Profile:Interleaved
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brickmaker
Aspiring Contributor
722 Views
Message 10 of 19

Re: FECn Errors

When I first moved to this property and signed up for BT Broadband my sync speed was 135 kb/s with a down line attenuation of 43 dB.

I removed the ring wire from both main and extension sockets and sync went up to 5500 kb/s.

 

But I always have a very high CRC up error count with the Home Hub 2.0. As the figure remains the same from the moment of switch-on I assume that is a Home Hub feature.

 

Unfortunately my SNR margin was increased from 6 dB to 9 dB during the training period, while I still had the problems with low sync due to the ring wirte, and I don't think it will ever go down as I get some errors of just about every type.

 

Do you have a ring wire and if so, have you tried disconnecting it? Ring wires aren't needed with modern phones, the ADSL filters carry out the same function, and a ring wire is a wonderful antenna for picking up interference.

 

Certainly you should not have such a low sync rate from the stats you give.

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