More About Slow Speeds

[#1]

I have had a Plusnet account for 1 month. It is up to 8mb. In practice the line will only allow 2mb.
Initially all was well the speed tester showed 1400kbps increasing to 1800 some days later. Since 3 days ago the speed has sunk to 130 with 2 tests today down to 50.
I ran a BT speedtest which showed: 
IP profile 135
DSL 448 UP 160 Down
Actual IP throughput 118
From this does it mean that Plusnet is limiting me to 135 kbps? And if so why?
Any ideas?

[#2]

It means that BT is limiting your speed, most likely due to "blip" logic.
If you disconnect, and reconnect at a very slow speed, BT adjusts your line profile to match - generally very quickly.
Your connection then has to subsequently "prove" that it is capable of sustaining a higher transfer rate, which will usually happen over 3-5 days, after which your IP profile will increase again.
I'm sure one of the PN staff can let you know when your router recorded a very low sync rate.  It is usually either noise on the line, or perhaps incorrectly filtered equipment that caused a bad sync.
BT have improved the "resync" time recently, dropping it down from 3-5 days to a much shorter margin (again, PN will be able to advise).  However, this isn't live on the PN platform as yet.
Barry

[#3]

Quote from: zubel

I'm sure one of the PN staff can let you know when your router recorded a very low sync rate.  It is usually either noise on the line, or perhaps incorrectly filtered equipment that caused a bad sync.

Here are the last 15 profile changes recorded by BT's systems:

135			11/08/2007 03:20:08
135			10/08/2007 07:54:18
500			10/08/2007 07:21:09
500			10/08/2007 07:21:09
500			10/08/2007 07:21:09
500			10/08/2007 07:21:09
500			10/08/2007 07:14:35
1500			10/08/2007 06:23:39
1500			10/08/2007 06:16:20
1750			10/08/2007 00:28:25
1750			10/08/2007 00:03:23
500			06/08/2007 10:35:37
500			05/08/2007 10:16:47
500			05/08/2007 10:03:25
1750			04/08/2007 22:31:03

Looks like things started going a little awry earlier this month. Before that your speeds fluctuated between 1500 and 2000.
Does this coincide with the introduction of any new telephony/electrical equipment to your premesis? Has the weather been particularly bad on the dates the speed profile dropped?

Quote

BT have improved the "resync" time recently, dropping it down from 3-5 days to a much shorter margin (again, PN will be able to advise).  However, this isn't live on the PN platform as yet.

See here for more detail. This should be in effect now.

[#4]

I've added no new telephony or electric equipment recently. As for the weather - I dont recall anything out of the ordinary for this strange summer.
I will check the filters etc
The speed has been down for several days, ibfact today is the slowest yet. If it was just a "blip" shouldnt it have started to improve by now?

[#5]

If your equipment has been consistently synchronised above 512kbps since 11/08/2007 03:20:08 then yes.
I'd keep a close eye on things and give it a few more days to see if it increases before reporting a problem.

[#6]

Do PN get a view of the target noise margin?  With all those re-syncs over a short period isn't it likely that BTw DLM will have increased the target SNR to try to stabilise the line?  That would push down sync speed.
Posting router stats (downstream and upstream sync speeds, noise margins & attenuations) could be helpful.