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Any capacity issues?

Melancholie
Grafter
Posts: 451
Thanks: 1
Registered: 23-07-2013

Any capacity issues?

Hey all,
Have noticed slight latency increases, especially on a Monday when the networks are usually busiest. This has now become accompanied by packet loss, implying rate limiting due to a congested port somewhere.

Is the SVLAN serving us a little busy please?
2,316 REPLIES
Community Veteran
Posts: 1,412
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Registered: 29-01-2009

Re: Any capacity issues?

I wouldn't even describe those changes in latency as "slight"! One extra yellow pixel (ie "max latency") can happen because 1 ping packet in every 100 takes 1ms longer. A tiny queue in a router somewhere for an unprioritised packet... which is basically nothing. You should expect some latency changes over the course of a day - particularly around the 9pm busy hour.
When you download something yourself, you tend to see taller yellow spikes. When you really run download tests, then you'll see even taller spikes. But they still mean almost nothing.
It only starts to means something when the blue band ("average latency") starts to increase ... and becomes worrying when the green band ("min latency") starts to increase.
The red packet loss is different. Yours still doesn't show a lot of loss, but it would be worth keeping an eye on, and compare a number of days.
However, I'm not sure that it shows any rate-limiting going on. Congestion, somewhere, would show a lot more queued packets - leading to large yellow areas plus an increase in the blue area of perhaps 5-10ms. Severe congestion (as seen in VM) would see the green area increase by 5-10-20ms, and a lot of yellow/blue colour elsewhere.
Here's an example of my line, back before I lost the FTTC during a house move:

That line shows a reasonable amount of use; the tallest spikes are when the SamKnows whitebox runs its performance tests. I'm not worried about anything shown on there.
Attached below is a much older graph that showed serious packet loss, caused by errors on the VDSL2 portion rather than any congestion; throughput stayed reasonable (I lost about 10% of download speeds because of this loss). You'll see when DLM intervened to get rid of the errors...
Plusnet Customer
Using FTTC since 2011. Currently on 80/20 Unlimited Fibre Extra.
Community Veteran
Posts: 26,657
Thanks: 886
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Registered: 10-04-2007

Re: Any capacity issues?

It's a shame he hasn't posted it as a link to the full size graph because it looks like there's a trace of red at the top which is abnormal and something to comment on.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
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Community Veteran
Posts: 1,125
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Registered: 14-08-2007

Re: Any capacity issues?

My graph is also showing some packet loss over the last 24 hours.

Edit: Graph link amended as per Jelv's suggestion below
Edit again: You are currently connected to gateway pcl-bng04.
Final? Edit: Looking at past days, I've been getting packet loss at that level since 18th Dec - which is as far as my graph goes back.
Community Veteran
Posts: 26,657
Thanks: 886
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Registered: 10-04-2007

Re: Any capacity issues?

Nothing showing on mine:

I'm on 20CN IPSC via ptw-ag03.
BTW: When posting the TBB graphs just copy all the code from the last share option (Small Graph (500x219 px) - BBCode (for forums; not yet supported on thinkbroadband forums)) which looks like this:
[tt][url=http://www.thinkbroadband.com/ping/share/a5c7bf46694ea80ac042f28ce9ecb9db.html][img]http://www.thinkbroadband.com/ping/share-thumb/a5c7bf46694ea80ac042f28ce9ecb9db.png[/img][/url][/tt]
That gives the thumbnail which can be clicked for the full size version as above.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
fibreuser
Grafter
Posts: 167
Registered: 28-05-2014

Re: Any capacity issues?

I too have started noticing packet loss over a number of days now.
I logged a fault with PN who said that the exchange is green for congestion (although didnt mention their own network) and said that if i wanted to progress the ticket that I would need to get an engineer out - which I declined as I dont think is a fault my side and dont want to get charged.
My TBB graph looks like this

Packet loss not so bad last night but the night before was worse.
(modified as changed IP on tbb graph)
Community Veteran
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Registered: 27-10-2012

Re: Any capacity issues?

Quote from: fibreuser
PN who said that the exchange is green for congestion

The BTW SVLAN spreadsheet hasn't been updated since 23 Dec.
There's been a lockdown of maintenance/upgrade programmes by BTW from 19 Dec until 6 Jan, so normal capacity upgrades wouldn't have taken place in that period.
I too have seen low level packet loss and there's a noticeable difference with HTTPx1 vs HTTPx6 downloads. I believe it's a backhaul issue as a couple of other ISP users on the same exchange as me have seen the same.
Melancholie
Grafter
Posts: 451
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Registered: 23-07-2013

Re: Any capacity issues?

As requested:

It's very low level but definitely the port is getting a bit busy. Looking back at historical speed tests they have been perhaps 10Mb down at peak times and latency rising slightly is regular.
No biggie and not breaching BTW KPIs. Thanks for the sanity check.
Melancholie
Grafter
Posts: 451
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Registered: 23-07-2013

Re: Any capacity issues?

Been reviewing some more and noted loss 28th - 30th of December. Lighter load on 31st I would hope hence no packet loss.
Will keep an eye on it and if it breaks BT Wholesale KPIs will ping support and ask for an SVLAN check on MYHLT.
Community Veteran
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Registered: 18-02-2013

Re: Any capacity issues?

I note you have some loss about now...

Taken from http://community.plus.net/ping-graphs/
Melancholie
Grafter
Posts: 451
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Registered: 23-07-2013

Re: Any capacity issues?

Yeah, people are off work and have just come back from scoring the sale bargains so peak time has been stretched Smiley
http://www.thinkbroadband.com/speedtest/results.html?id=142013087500656018289
Seems pretty unequivocal to me.
Melancholie
Grafter
Posts: 451
Thanks: 1
Registered: 23-07-2013

Re: Any capacity issues?

Ticket 97012277 raised.
Speed has degraded and is outside of BTWholesale range. Single-threaded performance is way off. Current profile on Plusnet's Procera kit is 64.2Mb.
Marksfish
Grafter
Posts: 321
Registered: 22-11-2014

Re: Any capacity issues?

Off topic slightly: I thought the TBB monitoring is only available for static ip addresses. Do you have to keep changing your graph when/ if you re- sync with a different address?
Mark
fibreuser
Grafter
Posts: 167
Registered: 28-05-2014

Re: Any capacity issues?

Yeah - you can seem to edit it just to change the IP unfortunately, unless someone knows something I dont!
Also , am I right in thinking that these sort of speed issues caused by BT backhaul would be less likely to happen on talktalk for example?
Melancholie
Grafter
Posts: 451
Thanks: 1
Registered: 23-07-2013

Re: Any capacity issues?

Quote from: fibreuser
Also , am I right in thinking that these sort of speed issues caused by BT backhaul would be less likely to happen on talktalk for example?

The only congestion issues I've seen on FTTC as far as Plusnet go have related to BT Wholesale capacity, which TalkTalk and Sky don't use out of exchanges they have unbundled.
This doesn't mean that TalkTalk and Sky don't have capacity issues of their own, but they don't use the BT Wholesale backhaul so aren't affected by issues on it.