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Sudden change of latency/speed (BT change?)

PeeGee
Aspiring Pro
Posts: 1,105
Thanks: 56
Fixes: 3
Registered: ‎05-04-2009

Sudden change of latency/speed (BT change?)

At approximately 13:00 yesterday, BQM indicated a few dropped packets and minimum latency doubled to about 20mS - there was no session drop. I later forced a gateway change (from pcl-bng02 to ptn-ag01) and, as expected, there was no difference. At the same time, the SamKnows monitored speeds dropped by about 6Mbps from the pcl-bng02 low (about 9Mbps from the previous steady rate on ptw-ag01and the pcl-bng02 high - it had frequent jumps between high and low) followed by a 3Mbps negative spike. ptn-ag01 seems to be holding a steady speed since taking over.
Rightly or wrongly, I conclude that BT have "done some maintenance" somewhere in the network (a quiet line test is quiet!) and also that pcl-bng02 is having problems with throughput (it's "connected users" figures are currently nearly double most of the other gateways, though the relative capacities are unknown) Shocked Roll eyes
Phil
Plusnet Fibre (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link Archer VR600 modem-router.
56 REPLIES
Philae
Newbie
Posts: 3
Registered: ‎29-01-2015

Re: Sudden change of latency/speed (BT change?)

Funny - a very similar thing has happened to me, but on Monday.
I keep a monitor running which pings 8.8.4.4 and Plusnet DNS (212.159.13.49) and records latency - it had been showing a very steady 10ms since we had fibre installed. At 13:00 on Monday 16th it jumped to 24ms, and has stayed there ever since. Line speed is still a good 35-40Mbps, and I'm not seeing any packet loss.
So I don't think there's a fault as such, but something has clearly been rerouted somewhere.
chall
Dabbler
Posts: 13
Registered: ‎06-01-2011

Re: Sudden change of latency/speed (BT change?)

At the risk of saying "me too!"..... uh.... "me too!"  Although my increase in latency occurred on Sunday 15th March at around 1pm in the afternoon according to TBB:    
Community Veteran
Posts: 6,319
Thanks: 86
Fixes: 3
Registered: ‎08-01-2008

Re: Sudden change of latency/speed (BT change?)

Here's my graph from 13th March when my line changed from Fastpath to Interleaved (I know this because my VDSL Router tells me):

This was when Interleaving switched off on 10th March (My line has been interleaved for a long time having recently just had this brief spell without interleaving):

Interleaving typically adds 8ms each upstream and downstream on my line (so steps of around 16ms are a typical symptom)
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
chall
Dabbler
Posts: 13
Registered: ‎06-01-2011

Re: Sudden change of latency/speed (BT change?)

Quote from: w23
Here's my graph from 13th March when my line changed from Fastpath to Interleaved (I know this because my VDSL Router tells me)

So that looks exactly like mine!  From around 10ms to around 25ms !
Unfortunately I don't have the luxury of a router that tells me if I'm on fastpath or interleaved (it's a TG582n).  Can someone from PN confirm?
If interleaved, how can it request this to be removed and set back to fastpath?
Community Veteran
Posts: 6,824
Thanks: 1
Registered: ‎27-10-2012

Re: Sudden change of latency/speed (BT change?)

Unfortunately, Plusnet cannot turn off interleaving for FTTC. You just have to wait for your line to become more stable and for it to be removed.
chall
Dabbler
Posts: 13
Registered: ‎06-01-2011

Re: Sudden change of latency/speed (BT change?)

Ok, so does this assume that my line has become unstable of interleaving to be applied?
What's the process time frame at play here - Just keep going and *evently hope* that interleaving will be turned off at some nondescript point in the future?
Community Veteran
Posts: 6,824
Thanks: 1
Registered: ‎27-10-2012

Re: Sudden change of latency/speed (BT change?)

Your line will be erroring for some reason.
It can range from a week or longer for interleaving to be removed. You need the errors to drop below a certain threshold though for this to happen.
mlmclaren
Grafter
Posts: 855
Registered: ‎04-12-2014

Re: Sudden change of latency/speed (BT change?)

Hi everyone, my connection has done similar, at 2am on Monday my connection resyncedI lost 4-5mbps download and minimum latency from 10ms to 27ms ?Huh
Plusnet haven't really been able to help though... sounds like a fault ... that they are refusing to send an engineer for!
See here for my issue: http://community.plus.net/forum/index.php/topic,137362.32.html
chall
Dabbler
Posts: 13
Registered: ‎06-01-2011

Re: Sudden change of latency/speed (BT change?)

Quote from: AndyH
Your line will be erroring for some reason.
It can range from a week or longer for interleaving to be removed. You need the errors to drop below a certain threshold though for this to happen.

Can I request a check of my line then please Plusnet peeps?
Cheers
Plusnet Help Team
Plusnet Help Team
Posts: 1,953
Thanks: 22
Fixes: 5
Registered: ‎24-07-2014

Re: Sudden change of latency/speed (BT change?)

Please find line test attached.
If this post resolved your issue please click the 'This fixed my problem' button
 Tony T
 Plusnet Help Team
chall
Dabbler
Posts: 13
Registered: ‎06-01-2011

Re: Sudden change of latency/speed (BT change?)

Thanks Tony.
Pass but a voice fault ? Um....
Plusnet Help Team
Plusnet Help Team
Posts: 1,953
Thanks: 22
Fixes: 5
Registered: ‎24-07-2014

Re: Sudden change of latency/speed (BT change?)

It's worth doing a quiet line test (17070) just to ensure it is OK. I've seen false positives with this sort of thing, so it is worth just checking.
If this post resolved your issue please click the 'This fixed my problem' button
 Tony T
 Plusnet Help Team
chall
Dabbler
Posts: 13
Registered: ‎06-01-2011

Re: Sudden change of latency/speed (BT change?)

OK, will do. Thanks Tony
JHewess
Grafter
Posts: 81
Thanks: 4
Registered: ‎20-11-2014

Re: Sudden change of latency/speed (BT change?)

Am jumping on this bandwagon. The same thing happened to me on the 16th just before 10am. I won't go in to details as I have both a forum thread and fault already for it, but suffice to say that my speed dropped from the high 70s to the high 60s and my latency has more than doubled with increased packet loss. However everything says it's not due to interleaving.  
It looks like there's a few of us experiencing the same thing occurring at around the same time which is an odd coincidence. I'd be curious to see if it's in any way geographically connected. I'm in the south east, and think I go via Faraday when my connection hits London (assuming that makes a difference).