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Line drops problem led to interleaving switchon but now sync speed down

Community Veteran
Posts: 1,229
Thanks: 1
Registered: ‎30-07-2007

Line drops problem led to interleaving switchon but now sync speed down

Some days ago I've saw that I'd had a few occasions when my ADSL connection has reset.
This is unusual as I am on a short stable line (<300M from exchange) and my router normally holds a connection for hundreds of hours without a resync. Note that the router itself doesn't restart (it's been running continuously for >1600 hours right now)
My stats at that time were:
Up Speed 448000
Down Speed 8128000
SNR Margin 13dB
Loop Att. 9dB
Exchange status green
The router log showed "PPP Closed : Remote Terminating (PPPoA)" whenever the line dropped so it looked like an exchange problem.
I raised a ticket and the response (after testing) was for interleaving to be turned on (and it came on almost immediately) since when (only 28 hours mind you) there's been no reset. However I noticed my speeds were also down, so I added the following to my ticket:
Quote
Interleaving is now on according to my router (and my latency has doubled so that confirms it)
BUT I also note that my stable rate has dropped to 6500 from 7000 and my router reports sync rate of 7616000 (donw from normal 812800) and my SNR Margin has bumped up to 15.5 from 13.
I didn't think interleave being on caused a reduction in sync speed?
Is it the recent sync failures that have resulted in BT resetting the BRAS?
can you clarify please?

the response has been
Quote
We have asked our wholesale broadband suppliers to turn interleaving on on your phone line to try and fix your current broadband problem.Interleaving is a form of error correction that helps to improve the stability of high-speed broadband. One drawback of interleaving is that it can increase ping times, which may cause problems for online gamers. We think that turning on interleaving may help with your connection problems. Interleaving usually takes 24 hours to turn on, but can take up to 5 days to take effect. If interleaving solves your problem, please close this Question. If you are still seeing problems with interleaving switched on, please return this Question to us with as much detail about your problem as possible. Thank you for your time and patience.
which is a cut'n'paste job if I ever saw one (and unsigned by the agent to boot).
I'll reset the router a couple of times in the next two days (can't do it 3 times as I'm going away) to see if that unsticks it, but I'm annoyed that CS apparently couldn't be bothered to read my question properly.
Can anyone here answer the question satisfactorily? 
Paul
5 REPLIES
Community Veteran
Posts: 3,789
Registered: ‎08-06-2007

Re: Line drops problem led to intervleaving switchon but now sync speed down

Turning interleaving on generally means the max attainable sync rate is 7616, as some of your connection speed will be used for error correction.
Whilst there have been reports of syncing above this level, it is a BT set margin so should be fairly standard.
Kitz's Site has an excellent technical walkthrough about Interleaving which may be worth reading.
B.
Community Veteran
Posts: 1,229
Thanks: 1
Registered: ‎30-07-2007

Re: Line drops problem led to intervleaving switchon but now sync speed down

Thanks Barry - brief, informative and to the point.
Pity your sig doesn't say the opposite
paul
Not applicable

Re: Line drops problem led to intervleaving switchon but now sync speed down

Don't suggest stuff like that! We've had a good run of retaining moderators, rather than allowing PN to pinch them - we don't want to have to start again..... Grin
Community Veteran
Posts: 1,229
Thanks: 1
Registered: ‎30-07-2007

Re: Line drops problem led to intervleaving switchon but now sync speed down

hehehe i might be a PN "secret shopper" ...
still i'm none the wiser as to why a previously solid (for two years) line suddenly went all fraggle on me
Community Veteran
Posts: 1,229
Thanks: 1
Registered: ‎30-07-2007

Re: Line drops problem led to intervleaving switchon but now sync speed down

After a while with interleave still on, normal stability resumed and a couple of emails from CS showing that line tests still indicate a High SNR/Low Attenuation line (which was the case before the line started dropping) ... The question still remains about why the exchange equipment started initiating disconnects, especially when all the line tests seem to indicate no problems with SNR ratio or attenuation.
Maybe there was a passing problem at the exchange?
I see that I can switch interleave on or off from the my connection settings control panel on the portal, and in a few days I think I'll turn it off and monitor the effect on line stability if any.
paul