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Contention?

mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

I have had this servive for about 6 months now. Recently i have experienced considerable differences between daytime and evening speeds. My line is rated at 2Mb/sec and in the morning i get around 1.8, sometimes even above 2Mb/sec.

I assume that the daytime speeds indicate that my OS and router are OK (Netgear DG632, a fragile beastie) and W98se.

These figures are from PlusNets own site

Evenings

25-01-2006 10:30:15 1873.
25-01-2006 20:00:50 137.8
24-01-2006 20:14:42 192.8
07-12-2005 20:57:44 485.2
17-11-2005 22:11:05 531.2
23-11-2005 21:27:04 663.6
25-10-2005 21:08:56 315.1
24-10-2005 20:18:54 134
21-10-2005 22:15:51 102.9
16-10-2005 21:35:35 1608.9
28-09-2005 21:03:42 971.7
19-10-2005 19:52:23 1208.7
18-09-2005 20:18:45 1835.4
5-09-2005 19:25:27 1827.4
12-09-2005 21:38:48 252.3

Daytime

02-12-2005 13:57:00 1693.7
18-11-2005 10:41:49 1796.5
27-10-2005 10:59:29 1476.3
24-09-2005 11:58:46 1871.3
24-09-2005 11:45:40 786.8

Just ran another test & am getting 244 Kb/sec. You will note that some evenings I get full speed, but not recently.

I have not as yet used the BT test as the daytime speeds suggest there is nothing wrong with my setup or the line.

My useage is low, about 50Mb so far this month. I cannot provide snr etc, the DG632 won't supply them. I did have one heavy month late last year but only just over 1Gb (Linux ISO image plus W2K SP4 (twice)(please don't ask)

Is this down to contention? Or are there other reasons? Is there anything to be done?
20 REPLIES
N/A

Contention?

It probably is down to contention, but it's difficult to tell if that's in BT's network or PlusNet's without doing some more checks.
If you use the Exchange Checker that may help, as there could be something like VP problems causing a slowdown during peak periods. Also, running the BT speedtest would eliminate PlusNet's network so show if it's a BT issue.
Unfortunately it is the nature of ADSL that you won't always get the maximum speed your line is capable of and this fact is only going to become more clear as line speeds increase. That said, if the BT speedtest consistently shows very low speeds that could help push for the exchange to be looked at.
mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

I replied to your post & the forum lost it and logged me out.

Try again.........

I will try the BT test & come back with the results.

We have overground line to a pole in the road, could it be the constant rain recently?

BT Exchange checker says all clear..

Thanks for the prompt reply
N/A

Contention?

rain *shouldnt* affect it that much. IT can but you wouldnt see that much difference unless you have a poor or damaged line

The Usertools Exchange Checker may not have been updated. BT are notorisly slow at updating it. IT could well be exchange contention. If even HTTP speeds are constantly low then i'd say its most lilkly not at plusnets end.

Can i ask what account your on? If its Premier there shouldnt be a problem. If its BB+ then plusnet might have the wrong profile attached to your account.
mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

All within the last 15 mins, and in this order

ADSLGuide 970Kbs
BT Tester 1212Kbs
PlusNet tester 301 Kbs

Looks like it might be a PlusNet problem, although the ADSLGuide test seems quite close to the BT results.

Strange.
mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

ps: it was 1800Kbs this morning..........
Community Veteran
Posts: 1,653
Registered: 13-06-2007

Contention?

try several PN speed tests, sometime it sends you a tiny file randomly giving you really off stats, make sure nothing else is using your connection when you try the PN speed test as well
mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

Just tried 4

2.4 Mb Download 818Kbs
576K " 575Kbs
2.4 Mb " 1653Kbs
450K " 596Kbs

Seems the larger the test file the faster the connection.

In normal surfing (I don't do P2P or OnLine games) I can see the connection changing speed as web pages load, some that load very fast will suddenly take several seconds to load.
Community Veteran
Posts: 1,653
Registered: 13-06-2007

Contention?

try this speed test its usually very accurate and gives you some very good stats about your connection http://www.auditmypc.com/internet-speed-test.asp
mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

Tried AuditmyPC and got 970Kbs

Other stats shown:

QOS DL 66% UL 71%
Max Pause 490
RTT Min 59 Max 220 Av 118

The Max Pause seems very high, not sure about the others, I'm no expert.

MTU is 1458 and RWin 56720 (open to advice on this figure, suggested by Kitz)

On the whole it does seem better today compared with the miserable DL speed of recent weeks, but still only half of what I get during the day.
passer
Grafter
Posts: 381
Registered: 06-04-2007

Contention?

@strathbungo - nice link Cheesy

So - if the auditmypc test gives me a speed of 1946 kbps, and the PlusNet test gives me this :

20-02-2006 20:52:38 926.1
20-02-2006 20:52:20 1042
20-02-2006 20:51:59 1085
20-02-2006 20:51:42 955.8
20-02-2006 20:51:27 1011.1
20-02-2006 20:51:07 1387.7
20-02-2006 20:43:12 913.6
20-02-2006 20:42:36 945.3

and then the auditmypc test gives me
1937 kbps/253kbps
max pause=79
qos dl=88% ul=100%
rtt min=46 max=156 av=106

my interpretation is that I have a pretty damn reasonable sort of ADSL link and PlusNet have bad contention problems. Would that be correct?

This morning at 08:05 my PlusNet speed was 1946 kbps, and most of the time it hovers around 1900, except during the evenings, when it goes crazily unpredictable. Noticeably worse on Monday and Friday evenings.

However - at 22.10, the auditmypc gives me this
964kbps/252 kbps
max pause=32
qos dl=61% ul=100%
rtt min=31 max=141 av=96

so now I'm very confused - maybe it's BT. :?
mutterer
Grafter
Posts: 36
Registered: 26-07-2007

Contention?

Join the club. I have spent so much time on this damn service that I am seriously thinking of going back to Dial up

It has just taken me 30 minutes to get back to this forum, modem disconnecting every 10 seconds. PlusNet supplied modem never worked from Day 1. Bought a PCI internal Modem, that never worked either. Neither would sync. Present Netgear router works when it feels like it but needs a reboot and a little rest with its feet up every other day.

Like you, evening speeds are all over the place, see start of this post.

Getting really, really fed up with it all.
Community Veteran
Posts: 26,352
Thanks: 606
Fixes: 8
Registered: 10-04-2007

Contention?

The following is my take on speeds - perhaps others could confirm if this is their experience.

Once the BT tester goes below about 1700, it's a sure sign that there is some exchange contention. The speeds you will get at any one moment will be dependant upon what the other users on your exchange are doing at the instant you run the test. I would therefore expect speeds at the point exchange contention starts to kick in to be highly variable. When the point that it is so bad that even BT admits there is a problem and sets the exchange to red, speeds will stabilise again - consistently bad.

If the problem is at Plusnet's end the number of users being contended against the available resources is much higher than at an individual exchange and so I would expect far less variability in the speeds.
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)
kitz
Rising Star
Posts: 817
Thanks: 46
Registered: 08-06-2007

Contention?

Yep thats about my experience..

Mild/Medium exchange contention (1000 - 1600) fluctuates quite erratically.

Yet when exchange contention gets pretty bad <600 then those fluctuations stay lowish over a small time frame.
By the time you get to below 400kbps they seem to stay like that for a few hours.

>> If the problem is at Plusnet's end the number of users being contended against the available resources is much higher than at an individual exchange.

Agreed.... like you say less variation in the speeds, because the number of users involved are higher.
N/A

Contention?

Quote
@strathbungo - nice link Cheesy

So - if the auditmypc test gives me a speed of 1946 kbps, and the PlusNet test gives me this :

20-02-2006 20:52:38 926.1
(Trimmed)

my interpretation is that I have a pretty damn reasonable sort of ADSL link and PlusNet have bad contention problems. Would that be correct?


Nope. If you are still connected to PN when you got the auditmypc results then the problem isn't with your ADSL connection but inaccuracies with PN's speed checker.