How do I get my sync rate back ?

[old Bill]

As some of you will know I had BT out a few days ago to do some work.  Because the guy disconected my line so much my sysnc dropped from around 5120kbps down to 4032kbps. I have left my connection on for the last four days and this morning unplugged it for a hour in the hope that my sync rate would go up.  When  I switched it back on my sync rate had no changed. Is there anything else I can try or is my line now stuck with a good connection buy lousy speeds ?

[DorsetBoy]

Your present synch rate should still give reasonable speeds Bill.

What you want to look at is your line profile.If you were disconnected too mnay times the profile may well have gone down to as low as 250k, if that is the case your speeds will be low no matter what synch you have.

Get a BT speedtest and see what that gives you,if the profile is low leave that router on and wait for the profile to come back up.

I just had four days at 250K and a synch of 6716k......not much fun.

[Lance]

Could it be that with all the disconnects, Bill, BT's equipment has raised the target SNR margin for your line? If this has happened it will cause you to sync lower, with the higher margin. What is your current noise margin sitting at?


edit for typo

[old Bill]

The router stats say 9.3 down and 9 up.

[Lance]

Then it sounds like its not that then. 

The only thing I can suggest is try to unplug it once or twice more and see if you get lucky. Remember not to do it more than 9 times in an hour, otherwise BTs equipment take it as a fault.

Maybe someone else will be able to offer more help.  8)

[Rik]

I'd agree with Dorset, Lance. Bill needs to do a BT speed test and find out what his profile is. Until we know that, we may make things worse rather than better with anything we suggest.

[Lance]

The way I read it is that he is simply trying to raise his sync in order to raise his profile. I took it that he meant his "lousy speeds" (which are higher than both mine and yours!) were being caused by him not being able to sync higher. Hence my line of thought!

[Rik]

My concern, Lance, is that if what is required is three days of patience, Bill may simply make things worse by continuing to try and force a higher sync speed. As you say, he's already got better speeds than us, so we should probably sulk at this point.

What I had missed, was the claim that the sync had dropped because the BT engineer disconnected the line so much. If he's now got lower sync speeds, the characteristics of his line have changed or DLM has decided that his line is unstable, and has increased his target noise margin. In either case, forcing re-syncs will not help.

Bill, we really need a BT speed test plus your line stats to advise you.

[old Bill]

Sorry perhaps I did not make myself clear. About 3 weels ago mr noise margin was set at 6db and I was sync at around 5120 and my profile was 4500kbps. I then had a interleaving problem and my noise margin went up to 9db  and and my profile dropped to 4000kbps. I then had the BT chap round last week and since then my profile has been.
Test1 comprises of Best Effort Test:  -provides background information.
   IP profile for your line is - 3500 kbps
   DSL connection rate: 832 kbps(UP-STREAM)  4064 kbps(DOWN-STREAM)
   Actual IP throughput achieved during the test was - 3232 kbps
So in the space of 3 weeks my profile has dropped quite a bit which was down to a fault with the interleaving. My line had been steady up till then. I would like to get the sync back to the orginal 5120.

[old Bill]

here are my line stats
System Up Time 02:36:06
Port   Status   TxPkts   RxPkts   Collisions   Tx B/s   Rx B/s   Up Time
WAN   PPPoA   7237   16218   0   67   1740   02:35:31
LAN   10M/100M   456   0   0   12   0   02:36:01
WLAN   11M/54M/270M   15989   7962   0   1791   87   02:35:54

ADSL Link   Downstream   Upstream
Connection Speed   4064 kbps   832 kbps
Line Attenuation   50.0 db   29.0 db
Noise Margin   9.1 db   9.0 db

[Rik]

Hi Bill

The only way you will get a faster sync is to have your target noise margin reduced back to 6db. For that attenuation and noise margin, I'd say your line is going at about the right speed. Do you have a note of what your attenuation was before the recent work?

What does concern me is that you only have 9db of u/s noise margin, that figure should be nearer 20db.

You need to talk to support, I'm afraid, to see if they can get your target margin re-set to 6db, however I'm not sure that it will stick, assuming BT agree to do it. Meantime, you should mention your u/s noise margin to them, that figure is way too low.

[Inactive]

Morning Bill,

You could perhaps have a word with your neighbour.

Your line must have had more attention than anyone else's in the country.

I reckon your only fix is to move.

Seriously, it does look like you are more or less stuffed for a fast and stable speed.

But I know sweet FA anyway... 

[old Bill]

The one thing that I dont understand is that even when the noise margin increased I was sync higher then i am now. When my noise margin went up my sync dropped by 500kbps then the BT chap came out and it dropped another 500kbps but my N/M has not increased again.

[Rik]

Has your attenuation changed, Bill. If it's increased with the wiring changes, that would cause a lower sync speed. The other possibility is that the nature of the noise on the line has changed, and so your are not able to use some of the frequencies, leading to lower sync speeds, ie if, during negotiation, the router rules out some of the lower frequencies because of the noise margin on them, it will end up using higher frequencies, which will result in greater attenuation and, therefore, lower sync speed.

[old Bill]

The strange thing is none of my stats have changed over the last week. The only thing i can try is ask C/S to lower my NM or see if they will reset my line both been BT dependent. My attenuation is still the same and the BT chap said that my neighbours wires were a lot better than mine.

[Rik]

The engineer's comments seem a little odd if, having swapped the exchange pair, you are not getting improved results, Bill. I think you will need to call support tomorrow and see what they can do.

[Inactive]

Bill. I think you will need to call support tomorrow and see what they can do.

You do know the number Bill?

It is 08000 267 237 

[old Bill]

I must remember to program it in to the phone.