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Plusnet Pro not achieving line speed

danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Plusnet Pro not achieving line speed

When I signed-up to Plusnet Pro I was told that I would see throughput close to Line Speed at all times. 
This doesn't seem to be the case, and it's often significantly less than the Line Speed.
For example, I've just run a BT Broadband Speed Test (19:30 in the evening):
Download speed achieved during the test was - 4714 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :7616 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 6500 Kbps
The throughput of 4.7 Mb/s is well below the IP Profile of 6.5 Mb/s?
I do occasionally see throughput of over 6 Mb/s, but this is unusual.
Why is this?  Is it likely to be a consequence of contention on the BT Wholesale circuit that provides the link to the exchange?
Any thoughts/comments much appreciated.
Thanks
17 REPLIES
Moderator
Moderator
Posts: 27,336
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Registered: ‎14-04-2007

Re: Plusnet Pro not achieving line speed

Welcome to the forum danpayne69 Smiley
Have you checked the status of your exchange at http://usertools.plus.net/exchanges/

Customer and Forum Moderator. Windows 10 Firefox 64.0 (64-bit)

Community Veteran
Posts: 26,744
Thanks: 954
Fixes: 10
Registered: ‎10-04-2007

Re: Plusnet Pro not achieving line speed

I've never found the speeds reported by the BT speed test that useful - the only thing I look at generally in it's results is the IP Profile. You are better off using http://www.mybroadbandspeed.co.uk/ or http://www.thinkbroadband.com/speedtest.html
Even then comparing the speed against the IP Profile may not be that useful as a number of other factors come in to play. If you are using a wireless connection it is very likely that your speeds will be lower. You may need to tune your MTU and RWIN settings to get better speeds.
What you should be doing is comparing your speed at different times of the day using the same tester (but not the BT tester). If you are seeing slower times in the evening to say around 9am then there is something to be looked at, but the most likely culprit will not be Plusnet but exchange contention. If you are still on 20CN you can mitigate that by going to Max Premium which as well as a faster upload gives you higher priority on the BT network - but it will cost you an extra £7.83.
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)
danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Re: Plusnet Pro not achieving line speed

Thanks for your replies guys.
The status of my exchange is GREEN.
I don't normally use the BT Speed Test, but wanted to check the IP Profile.  Other test tools tend to report slightly higher throughputs, but the results are consistent with the BT tool.
It's 10:30pm now, and I'm still only getting 5 Mb/s.
I'll take your advice and measure again later when there really should be very little contention on the exchange.
Thanks again for taking the time to reply.
Superuser
Superuser
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Registered: ‎06-04-2007

Re: Plusnet Pro not achieving line speed

The difference between sync speed and IP Profile is the effect of protocol overheads, ATM overheads are around 10% and TCP/IP another 3%. Measured data speeds are always significantly lower than even the IP Profile because connections have to be managed. Connections have to be set up, real data packets do not pack exactly into ATM cells, correct receipt of packets has to be confirmed - and missing or damaged packets requested again. MTU / RWIN* settings can be less than optimum for a particular server; if the server is busy there can be additional overhead waiting for that to respond. Then there's network and exchange contention.
The network performance graphs here show the network is busiest (upstream and downstream) from around 5PM until after 11PM and that does impact on speeds - connection management related as well as raw throughput.
* RWIN is managed dynamically on Windows Vista and 7.
David
danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Re: Plusnet Pro not achieving line speed

OK, just measured throughput again at 09:45 Sat morning, and still only seeing 5 Mb/s - same as yesterday evening (when contention should have been much higher), so I'd be surprised if the difference between my IP Profile of 6.5 Mb/s and the throughput I'm seeing is down to contention on the exchange, and as a "Pro" customer, I understand my traffic is prioritised on the Plusnet network.
Any more idea?  Should I get Plusnet support to take a look?
itsme
Grafter
Posts: 5,924
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Registered: ‎07-04-2007

Re: Plusnet Pro not achieving line speed

Are you connected to your router by ethernet or WiFi? If it's the latter do you know what speed you are connected at?
danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Re: Plusnet Pro not achieving line speed

Connected via Ethernet.  And in the past I have seen speeds up to 6.5 Mb/s.
danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Re: Plusnet Pro not achieving line speed

And just measured throughput again at 5pm; still 5 Mb/s.
Community Veteran
Posts: 26,744
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Registered: ‎10-04-2007

Re: Plusnet Pro not achieving line speed

What does https://portal.plus.net/my.html?action=stable_rate say for your current line speed?
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)
danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Re: Plusnet Pro not achieving line speed

Mmmmmmm...... The Line Speed reported on the Plusnet site is 5.5 Mb/s, which would explain why I'm seeing max throughput of around 5 Mb/s.
Is this value updated more regularly than the DSL Connection Rate reported on the BT Speed Test, as this reports 7.5 Mb/s?
pierre_pierre
Grafter
Posts: 19,757
Registered: ‎30-07-2007

Re: Plusnet Pro not achieving line speed

PN has to wait for a Delta report from BT before the PN profile is automatically updated
If you are lucky and one of the care team are on over the week end they can do it manually, other wise you will have to wait til Monday
jojopillo
Grafter
Posts: 9,786
Registered: ‎16-06-2010

Re: Plusnet Pro not achieving line speed

HI danpayne69,
I've just ran a line check and the speeds are inconsistent. I'm getting onto BT now to see if I can get that sorted.
Jojo Smiley
danpayne69
Newbie
Posts: 8
Registered: ‎11-02-2011

Re: Plusnet Pro not achieving line speed

Thanks Jo, can you let me know the outcome?
jojopillo
Grafter
Posts: 9,786
Registered: ‎16-06-2010

Re: Plusnet Pro not achieving line speed

Hi danpayne69,
That should have cleared now. I'm seeing 7150 both sides.
Jojo Smiley