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Contributor
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Sudden drop in speed + latency jump

Hello

 

Over the past week or so, my upstream SNR was jumping 1db up and down like a yo-yo.... almost looked like square waves on an oscilloscope. Never seen anything like it before. We've had bad weather before but it had never affected the line. The upload rate would tend to be between 11000-10500... but with the issues it suddenly dropped to as low as 7155!

 

Oh dear I thought, my line is going wrong yet again! Nearly 3 months ago, the phone line degraded to a point when a fault was finally found in the underground cabling. When that was fixed along with having the profile reset, things were working great again. The line was finally stable with steady SNR graphs.

 

Just before the weekend I see a big Openreach van doing some work in our cabinet, which may or may not have anything to do with resolving the strange things that were going on with the line(s) there?

 

Anyway, during the weekend the line was reset by DLM... so the line dropped from an IP profile of 42.13 down to 33.13 (or thereabouts), however, the maximum rate for upload is now slightly higher at 12467 and the maximum download rate is currently sitting at 49516 (it used to top about 50.5Mb). There's a now an even bigger gap between the actual connection speed and the maximum rate.

 

Also, the interleave value on the downstream jumped from 853 to 2553! DLM was never applied to the upstream, and it's now set at 223.

 

As a result, my pings have increased by around another 20ms+

 

Now reading the forum, it appears DLM doesn't automatically return things back to how they were? The SNR graphs appear stable again so perhaps Openreach did repair something?

 

Is there anyway to request a DLM reset without risking the £129 or thereabouts charge if no fault is found with the line? Or should someone be called out to check the line first?

 

Any help or advice is appreciated!

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Contributor
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Message 2 of 2

Re: Sudden drop in speed + latency jump

Update:

 

Surprisingly, at around 6am this morning, DLM kicked in.

 

The IP profile is ~33.13 Mb, however the Interleave level for downstream has increased further to 2803, and it's back to 1 on the upstream.

 

The maximum rates are set to 11789 kbps for the upload, and 39203 kbps for the download.

 

SNRM up is 6.2db, and 6.1db for down at this time.

 

The pings are still higher than normal, and the IP profile is nowhere the 42.13 Mb that it was prior to all the strangeness going on.

 

I've read elsewhere about the 'square wave' effect on the upload SNR graphs. Some blame it on crosstalk issues. Some have recommended turning the OR modem off overnight?

 

Any thoughts and advice are welcome!

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