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ADSL2 line training - what to expect?

mgillespie
Grafter
Posts: 222
Registered: 08-04-2007

ADSL2 line training - what to expect?

Before I got my line upgraded to ADSL2, I had 0 TX and 0 RX errors at a rock solid 8Mbit/sec
I am now seeing an increasing count of RX CRC errors, is this normal during the training period (i'm guessing training involves turing the wick back until the CRC errors stop?)
My Line stats currently show:

ADSL Information      ( ADSL Firmware Version:  2471201_A)
  ATM Statistics TX Cells RX Cells TX CRC errs RX CRC errs
              484780     13091268   0          11869

ADSL Status Mode State Up Speed Down Speed SNR Margin Loop Att.
  ADSL2+(G.992.5) SHOWTIME 443928 15768266 7 27

Which is a slightly slower sync speed than yesterday
11 REPLIES
Community Veteran
Posts: 38,441
Thanks: 1,017
Fixes: 61
Registered: 15-06-2007

Re: ADSL2 line training - what to expect?

It tunes the circuit until an acceptable error rate is reached.
It is possible that the default nose margin has increased from 3dB to 6dB
You are leaving the router on all the time I assume
mgillespie
Grafter
Posts: 222
Registered: 08-04-2007

Re: ADSL2 line training - what to expect?

The router is on all the time.  I did reboot it last night, as there is some firmware with a different modem code that is recommended by Draytek to be better for ADSL2+ so I loaded that.
Community Veteran
Posts: 38,441
Thanks: 1,017
Fixes: 61
Registered: 15-06-2007

Re: ADSL2 line training - what to expect?

If you rebooted in the evening then you would get a slower speed
The error rate is very low so no problem there
I would just leave it alone until after the training period then you can ask for the upstream to be uncapped
sjrinfroyle
Grafter
Posts: 895
Registered: 08-05-2011

Re: ADSL2 line training - what to expect?

Quote from: Oldjim
The error rate is very low so no problem there

I wouldn't exactly call the error rate low:
Quote from: ClashcityRocker
ADSL Information       ( ADSL Firmware Version:  2471201_A)
 ATM Statistics TX Cells RX Cells TX CRC errs RX CRC errs
              484780     13091268   0          11869

If you aren't having any speed problems, I wouldn't worry however.
I would expect a maximum of sync speed of about 17Mb/s and a maximum download speed of about 16Mb/s.
Community Veteran
Posts: 38,441
Thanks: 1,017
Fixes: 61
Registered: 15-06-2007

Re: ADSL2 line training - what to expect?

As the previously reported speed was 8Mb/sec I assumed that the line was on Fast Path and that this would have carried over.
On that basis I considered that the error rate was low
On the other hand - if the line was interleaved - I would agree that they are a bit high
jojopillo
Grafter
Posts: 9,786
Registered: 16-06-2010

Re: ADSL2 line training - what to expect?

Hi ClashcityRocker,
Interleaving is currently off so that's probably the reason you're seeing the errors. I'm sure putting interleaving on would rectify that.
Jojo Smiley
mgillespie
Grafter
Posts: 222
Registered: 08-04-2007

Re: ADSL2 line training - what to expect?

I did raise a ticket ages back when I was on ADSL Max, to switch interleaving off, and I continued to have a rock solid connection (zero disconnects, and only a handful of RX errors over many months of use, my router uptime is really good).
Should I request that interleaving is enabled on my line now I have ADSL2?
I see alot of pages that "stall" and the error rate continues to rise.
Should I wait until the training period is over?
What's the deal with the upload uncap? 
Thanks.
jojopillo
Grafter
Posts: 9,786
Registered: 16-06-2010

Re: ADSL2 line training - what to expect?

I'd certainly wait for the training period to finish. It will probably be best to switch interleaving on if you're having these problems. On ADSL2+ you can upcap the upload, but I would see if we can get your line stable before we do that. Smiley
mgillespie
Grafter
Posts: 222
Registered: 08-04-2007

Re: ADSL2 line training - what to expect?

Hi, line has stabilized, and I think the training period is over.  There are still a few errors, but nothing like before.

ADSL Information      ( ADSL Firmware Version:  2471201_A)
  ATM Statistics TX Cells RX Cells TX CRC errs RX CRC errs
  6022655 20138927 0 1088
  ADSL Status Mode State Up Speed Down Speed SNR Margin Loop Att.
  ADSL2+(G.992.5) SHOWTIME 444937 16045714 5 27

Would it be possible to turn ON interleaving and uncap the upload.    Thanks.
mgillespie
Grafter
Posts: 222
Registered: 08-04-2007

Re: ADSL2 line training - what to expect?

Question #52784298
Plusnet Alumni (retired) orbrey
Plusnet Alumni (retired)
Posts: 10,540
Registered: 18-07-2007

Re: ADSL2 line training - what to expect?

Hi ClashcityRocker,
I've placed the order for you, should complete tomorrow. The upstream will be uncapped, and it will turn interleaving on (though at present it's on 'auto' and turned on).
Hope that helps.