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Author Topic: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)  (Read 5008 times)

blue166

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Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« on: October 22, 2019, 06:48:16 PM »

Hi All,

I am looking for some support with this issue.

Basically the connection has been running great since 2013 with only one issue back in 2018 that an engineer visit fixed on the first occasion. The connection has been running full speed 80/20 - real world about 74-75mb download and 18-19mb upload. With a latency of 6ms.

That was until the early hours of Monday at around 1:45am (ish) when the latency has jumped by 8ms and download speed has gone down to around 63mb. Upload speed has pretty much remained normal for me.

My set up is a MK4 faceplate with a 5C master socket. ECI Openreach modem connected to an ASUS RT AC86u router. The set up has been great and before that was connected to an ASUS RT N66u which was also brilliant.

I did wait to see if any change over night and nothing so I now have alarm bells ringing. Something with the connection has gone a miss. Speed tests with the download seem to flat out at around 63mb and feels like it could go higher but being prevented. It isn't bouncing down and up its flat out 63 so that's why it feels it wants to go higher (I could be wrong).

The latency jump and this indicates interleaving but unsure why?

Obviously with the above setup I have no access to line stats (I know...) - Is there a pattern that points towards anything in particular?

Here is a tracert to bbc.co.uk...
  1    <1 ms    <1 ms    <1 ms  router.asus.com [192.168.1.1]
  2    11 ms    11 ms    11 ms  172.16.10.67
  3     *        *       14 ms  31.55.186.181
  4    14 ms    14 ms    14 ms  31.55.186.188
  5    15 ms    15 ms    15 ms  host213-121-192-54.ukcore.bt.net [213.121.192.54]
  6    15 ms    15 ms    15 ms  peer7-et-4-1-0.telehouse.ukcore.bt.net [194.72.16.132]
  7    15 ms    15 ms    15 ms  peer5-te0-9-0-32.telehouse.ukcore.bt.net [195.99.126.81]
  8    14 ms    14 ms    15 ms  151.101.0.81

Here are some pics...

Many thanks in advance.
« Last Edit: October 22, 2019, 06:51:48 PM by blue166 »
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burakkucat

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #1 on: October 22, 2019, 07:30:57 PM »

It's very difficult to say.  :(

At a guess, I wonder if a new configuration profile was loaded into the ECI MiniShelf Hi-FOCuS M41 DSLAM and, post load, the device was warm-reset?
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benji09

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #2 on: October 22, 2019, 10:26:15 PM »

  The last, but one, fault on my broadband that affected my speed was due to my phone line becoming unbalanced, causing my land line phone to be useless due to a high hum level. The cable pair got changed, and broadband fault went...................
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burakkucat

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #3 on: October 22, 2019, 10:32:50 PM »

  The last, but one, fault on my broadband that affected my speed was due to my phone line becoming unbalanced, causing my land line phone to be useless due to a high hum level. The cable pair got changed, and broadband fault went...................

Good point. What you have described reads like an "earth contact fault" and such a fault does severely degrade the AC balance of the circuit.

I wonder . . . blue166, have you performed a quiet-line test from a (wired) telephone?
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ktz392837

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #4 on: October 23, 2019, 12:25:32 AM »

This sounds like interleave may have been applied to the connection?  Do you have any before and/or after modem stats?  Resyncing in the early hours seems to indicate DLM has detected a problem and is trying to see if interleaving will help.  Thunderstorms, new crosstalker, engineers touching cables, phone line problem, act of god could all be the cause.  Without stats not sure if we can be anymore specific if it is a permanent change or if it is could be temporary.
« Last Edit: October 23, 2019, 12:29:43 AM by ktz392837 »
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blue166

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #5 on: October 23, 2019, 07:29:14 AM »

Hi Guys,

Many thanks for the input I really appreciate it. Something appeared to happen last night again at 1:15am (ish) The latency has currently gone back to what it was before. Upload speed remains normal for me. Download is around 2.5mb lower coming in at around 72-72.5mb - before this was around 74-75. I guess I am best just leaving it and not doing anything else in the meantime??

I guess I won't know whether I will get that extra speed back or not. Just waiting i suppose?

BT have offered me a smart hub foc as i am under contract. If I was to get this id imagine if I ever needed stats I could connect that and look through error logs etc... and line stats sync speeds etc...?

What do you think?

Here is another pic and tracert this morning...

tracert bbc.co.uk
  1    <1 ms    <1 ms    <1 ms  router.asus.com [192.168.1.1]
  2     4 ms     3 ms     4 ms  172.16.10.67
  3     *        6 ms     6 ms  31.55.186.181
  4     6 ms     6 ms     6 ms  31.55.186.188
  5     7 ms     7 ms     7 ms  core3-hu0-17-0-9.faraday.ukcore.bt.net [213.121.192.54]
  6     7 ms     7 ms     7 ms  peer7-et-4-1-0.telehouse.ukcore.bt.net [194.72.16.132]
  7     7 ms     7 ms     7 ms  peer5-te0-9-0-32.telehouse.ukcore.bt.net [195.99.126.81]
  8     7 ms     7 ms     6 ms  151.101.0.81

Also in regards to above and quiet line test. I have tried this over the last few days. I am not sure it's any different to usual. but then again I am not 100% sure. I will do another one now just to try my morning fresh ears...

Edit - I have just done another quiet line test (with a corded phone) and it sounds ok to my ears. I would describe it same as usual. So I think that seems fine. There wasn't any evident loud hisses,pops or crackles that I could tell.

Many thanks in advance
« Last Edit: October 23, 2019, 07:42:25 AM by blue166 »
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ktz392837

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #6 on: October 23, 2019, 10:47:35 AM »

I bow to the more experienced members but due to the early morning resyncs it does seem something happened to the line, DLM intervened and enabled Interleaving causing drop in sync speed and increased ping and then decided the line didn't need any interleaving just a slightly reduced sync to keep errors under control. 

Gut feeling new cross talker impacted your line, DLM has intervened sorted it out and you have lost a very small amount of speed.  Given new cross talkers can drop your speed by 10-20Mb it could have been much (MUCH) worse. 

The trick will be is the line stable enough if not interleave may be reapplied if you manage a few days without intervention hopefully you are sorted until another cross talker appears :(
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blue166

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #7 on: October 23, 2019, 01:17:46 PM »

I bow to the more experienced members but due to the early morning resyncs it does seem something happened to the line, DLM intervened and enabled Interleaving causing drop in sync speed and increased ping and then decided the line didn't need any interleaving just a slightly reduced sync to keep errors under control. 

Gut feeling new cross talker impacted your line, DLM has intervened sorted it out and you have lost a very small amount of speed.  Given new cross talkers can drop your speed by 10-20Mb it could have been much (MUCH) worse. 

The trick will be is the line stable enough if not interleave may be reapplied if you manage a few days without intervention hopefully you are sorted until another cross talker appears :(

I shall keep an eye on things and report back.

I suspect with what you mention about crosstalk it's probably the main culprit. I have done well not to see the effects of it on my line in the 6 years of having my FTTC connection. It's probably been slowly eating away of my higher figures but I still had enough speed in the bank not to notice. Now its eating into my actual speeds :(
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burakkucat

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #8 on: October 23, 2019, 04:36:29 PM »

Also in regards to above and quiet line test. I have tried this over the last few days. I am not sure it's any different to usual. but then again I am not 100% sure. I will do another one now just to try my morning fresh ears...

Edit - I have just done another quiet line test (with a corded phone) and it sounds ok to my ears. I would describe it same as usual. So I think that seems fine. There wasn't any evident loud hisses,pops or crackles that I could tell.

Many thanks in advance

If your circuit was experiencing an earth contact fault you would certainly know it! In the light of the above results we can rule out any obvious faults.
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blue166

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #9 on: October 23, 2019, 07:05:59 PM »

If your circuit was experiencing an earth contact fault you would certainly know it! In the light of the above results we can rule out any obvious faults.

Many thanks,

I think I have grown to the fact that crosstalk has got me :(
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burakkucat

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #10 on: October 23, 2019, 07:37:49 PM »

I think I have grown to the fact that crosstalk has got me :(

Unfortunately it does, now, look like that is the case.
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kitz

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #11 on: October 25, 2019, 12:48:53 AM »

I bow to the more experienced members but due to the early morning resyncs it does seem something happened to the line, DLM intervened and enabled Interleaving causing drop in sync speed and increased ping and then decided the line didn't need any interleaving just a slightly reduced sync to keep errors under control. 

Gut feeling new cross talker impacted your line, DLM has intervened sorted it out and you have lost a very small amount of speed.  Given new cross talkers can drop your speed by 10-20Mb it could have been much (MUCH) worse. 

The trick will be is the line stable enough if not interleave may be reapplied if you manage a few days without intervention hopefully you are sorted until another cross talker appears :(

In the absence of detailed line stats, I concur with your gut instinct, but I have a little bit more to add.

If the DLM intervened at 1:30 am on Monday, then "Something" happened on Sunday causing DLM to add Interleave and Error Correction.   
The Error correction overheads will have caused the loss decrease in sync and throughput speed.

The fact that DLM put it right again within a couple days suggests that
1) It must have been on profile INP=3
2) It was a 1st offence and hopefully a one off caused by a single burst of errors.

I doubt DLM has anything more to give back - if it had gone to INP=4.5 the other day, then it would have taken longer for the latency to return to normal.

Back to the topic of crosstalk - DSM (dynamic spectral management) makes it less likely that sync speeds remain the same during periods of sync.   
Power goes up and down depending upon crosstalk situation meaning more variable sync speeds.   I mentioned about a week ago about the possibility of power wars between you and a neighbouring cross-talker depending on who sync'd first - more so now than previously.

Mine is doing some weird things right now as I see DSM stepping down my power.   
To add insult to injury I've also been interleaved after a single spike of CRCs/ErrSecs lasting for one minute and DLM still hasn't forgiven despite it now being over a week.   Mine isn't first offence though so it's taking longer :/     
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blue166

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #12 on: October 25, 2019, 02:57:23 AM »

In the absence of detailed line stats, I concur with your gut instinct, but I have a little bit more to add.

If the DLM intervened at 1:30 am on Monday, then "Something" happened on Sunday causing DLM to add Interleave and Error Correction.   
The Error correction overheads will have caused the loss decrease in sync and throughput speed.

The fact that DLM put it right again within a couple days suggests that
1) It must have been on profile INP=3
2) It was a 1st offence and hopefully a one off caused by a single burst of errors.

I doubt DLM has anything more to give back - if it had gone to INP=4.5 the other day, then it would have taken longer for the latency to return to normal.

Back to the topic of crosstalk - DSM (dynamic spectral management) makes it less likely that sync speeds remain the same during periods of sync.   
Power goes up and down depending upon crosstalk situation meaning more variable sync speeds.   I mentioned about a week ago about the possibility of power wars between you and a neighbouring cross-talker depending on who sync'd first - more so now than previously.

Mine is doing some weird things right now as I see DSM stepping down my power.   
To add insult to injury I've also been interleaved after a single spike of CRCs/ErrSecs lasting for one minute and DLM still hasn't forgiven despite it now being over a week.   Mine isn't first offence though so it's taking longer :/     

Hello,

Many thanks for the help and input once again.

In terms of gaining stats I do have an Huawei modem I purchased from Ebay 3 or 4 years ago in stock. I don't believe it was unlocked at the time and not sure what I would have to do to unlock it? - Also not sure how ot would get a long with the ECI cab?

BT did also tell me while in contract I can get a smart hub. I presume that would give me all the stats too? And I could use it then disconnect it again to go back to stand a lone modem. Obviously would not want to be doing many power downs etc... as DLM would go berserk. What you think?
« Last Edit: October 25, 2019, 03:00:44 AM by blue166 »
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Chrysalis

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #13 on: October 25, 2019, 05:46:34 AM »

In the absence of detailed line stats, I concur with your gut instinct, but I have a little bit more to add.

If the DLM intervened at 1:30 am on Monday, then "Something" happened on Sunday causing DLM to add Interleave and Error Correction.   
The Error correction overheads will have caused the loss decrease in sync and throughput speed.

The fact that DLM put it right again within a couple days suggests that
1) It must have been on profile INP=3
2) It was a 1st offence and hopefully a one off caused by a single burst of errors.

I doubt DLM has anything more to give back - if it had gone to INP=4.5 the other day, then it would have taken longer for the latency to return to normal.

Back to the topic of crosstalk - DSM (dynamic spectral management) makes it less likely that sync speeds remain the same during periods of sync.   
Power goes up and down depending upon crosstalk situation meaning more variable sync speeds.   I mentioned about a week ago about the possibility of power wars between you and a neighbouring cross-talker depending on who sync'd first - more so now than previously.

Mine is doing some weird things right now as I see DSM stepping down my power.   
To add insult to injury I've also been interleaved after a single spike of CRCs/ErrSecs lasting for one minute and DLM still hasn't forgiven despite it now being over a week.   Mine isn't first offence though so it's taking longer :/     
sadly i expect its a 2 week wait

you have a link to your stats anywhere?
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blue166

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Re: Speed Drop Of Over 10mb & Increase In Latency By 8ms (Plz Help)
« Reply #14 on: October 25, 2019, 04:51:11 PM »

sadly i expect its a 2 week wait

you have a link to your stats anywhere?

Part of the issue with ECI modem is no stats. BT have offered to send a smart hub. Shall I just take it and plug it in for stats and for going forward if need stats?

I do prefer my ASUS RT AC86U and stand a lone modem ideally for normal use though.

Is it worth powering down my equipment. (Was going to for a firmware update for router) or just leave things be for now?

Thanks
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