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[sevenlayermuddle]

I tempted fate a couple of days ago by mentioning that my (much) better than expected sync speeds were still persisting, a month into the service.

And then guess what...  my connection dropped for a few minutes about a half hour ago, then reconnected with a DS rate of 42, vs the circa 50 I'd enjoyed.  The only other drops in the past two or three weeks all occurred between midnight and 1am last Friday morning when it reconnected three times at, mysteriously, exactly the same US/DS sync rates each time.

I don't know whether my DS reduction is DLM action, or crosstalk as neighbours come on board, but either way it felt inevitable.  I've been telling the neighbours how awful FTTC was, and how they wouldn't like it, but this may be proof that they never listen to me.   

I did risk incurring the further wrath of DLM a moment ago by manually power cycling the modem in the hope that this was just a glitch, bit no - 42 seems to be my new DS rate.   

[roseway]

That's a shame. I don't recall what modem you're using, but do you have access to the stats? Things like interleave level might indicate whether it's DLM action.

[sevenlayermuddle]

Connection should be pretty optimal, modem right next to SSFP on master socket.

But I'm using the BT modem as-is with my own router, so no stats at all.   Even the connection rates are only available because Zen make them accessible in their portal.

I'm trying to resist the temptation of a 3rd party modem, or of unlocking the BT, as I fear that stats analysis would just become a time-consuming distraction.   And those who know me well sometimes tell me my obsessive nature is highly prone to such distractions obsessions.   

[Dray]

Once you've unlocked the modem and set the stats collection up, it's all automatic.

[kitz]

I should imagine crosstalk is the most likely culprit.   If you'd have been monitoring your SNRm, then the typical sign is a sudden step drop of noise margin that never recovers.   I guess your neighbours decided to ignore your advice not to get FTTC 

I also had 3 resyncs between midnight and 1am this morning, these being the only drops so far apart from those caused by me powering modem off when experimenting.   In each case there was apparently no change whatsoever in DS or US rate, so I wonder if it was false reporting somehow? 

BTw are carrying out a lot of over night work atm on the RASes and most areas will be affected at some point. 
FTTC users are the first to be moved on to the new MSE's and theres an awful lot of PEWs about the re-routing and ongoing work.

One of the benefits of the new MSEs is slightly less latency, so you may notice your ping times drop by 1ms or so -  depending on your own location, distance from your ISPs PoP and also distance between the old RAS and the new MSE.   

[sevenlayermuddle]

Once you've unlocked the modem and set the stats collection up, it's all automatic.

Yes but the amount of time spent by me analysing these stats is what I'm trying to resist. 

One of the benefits of the new MSEs is slightly less latency, so you may notice your ping times drop by 1ms or so -  depending on your own location, distance from your ISPs PoP and also distance between the old RAS and the new MSE.   

I've not been writing down the numbers, but pretty sure my ping times haven't changed... speedtest.net says 23mS, and command-line ping of my favourite server comes in about 21mS.  I'm thinking that makes it more likely crosstalk, assuming FTTC DLM, like IPStream,  hits interleaving first before any SNRM adjustments?

[kitz]

No this mornings drop in speeds are highly unlikely to be anything to do with the MSE/RAS, but your disconnects the other night would likely be.  Last month BT did loads of work on the MSEs which is what I was referring to re your post on the disconnects last week.

You are correct though,  in that if your ping time hasnt increased then its unlikely to be DLM..  in which case unlikely to be line instability.  DLM applies interleaving first.  With FTTC DLM theres no SNRm adjustments, it uses banding.

Mind you 21ms could mean that youre already interleaved?  I cant recall which part of the UK you are in, but if you are down south 21ms is a bit higher than I'd anticipate.   Whats your ping time to the BBC?

[Chrysalis]

given the time of day its most likely crosstalk and very unlikely DLM, bad news I am afraid.

[sevenlayermuddle]

Mind you 21ms could mean that youre already interleaved?  I cant recall which part of the UK you are in, but if you are down south 21ms is a bit higher than I'd anticipate.   Whats your ping time to the BBC?

That's my 'favourite server', so yeah 21 mS to BBC.  I am indeed down South, home counties.

I ought to add that I am still a happy bunny, despite what I may tell neighbours.

Yesterday, after updating one of my test devices to iOS 8.1, I suddenly faced an unanticipated need to update to the latest version of Xcode (Apple's IDE), in the form of a disc image download nearly 3GB.  A few weeks ago that would have taken well over two hours and written of pretty much the whole afternoon.  Instead, it was over in about 10 minutes - time to boil the kettle and drink a cuppa.  Even if it took 15 minutes, I'd still be happy 

Uploading Apps for testing is similarly transformed.  That might previously have taken 10 minutes, now reduced to more like 20-30 seconds - much more affordable.

[Chrysalis]

I should imagine crosstalk is the most likely culprit.   If you'd have been monitoring your SNRm, then the typical sign is a sudden step drop of noise margin that never recovers.   I guess your neighbours decided to ignore your advice not to get FTTC 

I also had 3 resyncs between midnight and 1am this morning, these being the only drops so far apart from those caused by me powering modem off when experimenting.   In each case there was apparently no change whatsoever in DS or US rate, so I wonder if it was false reporting somehow? 

BTw are carrying out a lot of over night work atm on the RASes and most areas will be affected at some point. 
FTTC users are the first to be moved on to the new MSE's and theres an awful lot of PEWs about the re-routing and ongoing work.

One of the benefits of the new MSEs is slightly less latency, so you may notice your ping times drop by 1ms or so -  depending on your own location, distance from your ISPs PoP and also distance between the old RAS and the new MSE.   

First I heard of these MSE's unbelievable is various rural areas having one and still none in Leicester?  you said the list is incomplete, is it possible to check if Leics has one?

[kitz]

Leicester Central still has several old type VPs but many SVLANs of type1 and 2 so I should imagine theres a very strong possibility of an MSE  location. Because Ive not seen it on any of the PEW lists, it may have been one of the first to go live (pre Nov 2013).   Thats just guess work on my part though.

Braunstone is another possible location that I suspect may have its own MSE.

[Ixel]

No this mornings drop in speeds are highly unlikely to be anything to do with the MSE/RAS, but your disconnects the other night would likely be.  Last month BT did loads of work on the MSEs which is what I was referring to re your post on the disconnects last week.

You are correct though,  in that if your ping time hasnt increased then its unlikely to be DLM..  in which case unlikely to be line instability.  DLM applies interleaving first.  With FTTC DLM theres no SNRm adjustments, it uses banding.

Mind you 21ms could mean that youre already interleaved?  I cant recall which part of the UK you are in, but if you are down south 21ms is a bit higher than I'd anticipate.   Whats your ping time to the BBC?

Not always. DLM can apply speed banding first (e.g. in my case with the multiple re-syncs). It can also change the min/max rate if the attainable rate has changed significantly. It may be that DLM adjusted his speed banding to better suit his current attainable rate.

[kitz]

    That's my 'favourite server', so yeah 21 mS to BBC.  I am indeed down South, home counties.

I suspect that you may already be interleaved, as you know Im oop norf and my latency to the BBC is 14ms.  I was subjected to the MSE/RAS changes last month, which lopped 1-2ms off my latency (prev 15/16ms for years).   The other week when I was interleaved by the DLM, it increased my ping times to 21/22ms from 14/15ms.

Not always. DLM can apply speed banding first (e.g. in my case with the multiple re-syncs). It can also change the min/max rate if the attainable rate has changed significantly. It may be that DLM adjusted his speed banding to better suit his current attainable rate.

Cheers.. although Im beginning to suspect the line was already interleaved, so banding is a possibility anyhow.
Its a bit hard to guess when we havent got stats or previous history.

----
Post edited to merge with another post, so I could split something that was OT

[sevenlayermuddle]

It may have already been interleaved by DLM as I pushed my luck in the first week or so, experimenting with the effects of different router modem locations and modem leads, and how a shielded lead performed vs unshielded, etc.   That involved a number of manual restarts, which may have got noticed by DLM.  I doubt whether I exceeded 4 restarts in any hour, or 6 in any day, something like that order.

I thought at the time I had got away with it but in the absence of hard stats, can't be sure. Nor can I be sure whether the ping started off at a lower value prior to that early experimentation - just that I think it has been 21mS-ish ever since and still is, despite the DS reduction.

The ZEN portal includes a chart named 'Service Profile data' that used to list DLM/BRAS activities for 20 cn. I know it used to work because it still shows a DLM SNRM adjustment that I know to be accurate, from earlier in the year.  I am not expecting that part of the portal to function for FTTC and indeed, there has been nothing new shown since my switch to FTTC, from which I draw no conclusions.

[roseway]

I suspect that you may already be interleaved, as you know Im oop norf and my latency to the BBC is 14ms.

I'm darn sarf and my latency to the BBC is also 14 ms, so you could be right.