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A bit of a strange one

leejonoloughlin
Dabbler
Posts: 20
Registered: 29-12-2010

A bit of a strange one

Hi guys,
First of all its been a while since ive had to ask for help! service is superb btw Smiley
Anyways got the adsl 2 change over done about a week or so ago and no matter how hard i try i cannot get any download speeds past about 12.5 mbps
heres the stats
results from bt speedter are
Download speed 12.16 Mbps this is a max ive had anything as low as 3.5
BT IP profile 18.52 Mbps
Plusnet line speed = 21 Mbps
Actual router sync speed =  20987
max attainable rate = 23940
snr 3.2
attenuation 20.5
something  just dosent add up to me i can understand not being full rate but to lose at least 4 Mbps no matter what the time of day the tests are run at seems real strange. yes there have been a few disconnects as i factory reset eveything on my router to makesure its not funky hardware but to no avail.
could you have a looky for me and see if there are any problems please
thanks
Lee
9 REPLIES
x47c
Grafter
Posts: 878
Registered: 14-08-2009

Re: A bit of a strange one


As a guess you are seeing lots of errors on the line.
But not enough to warrant the exchange raising the target margin to 6 - it's now clearly running at a 3 target
Lots of errors mean the router is spending it's time having to ask for the packets to be re-sent from the exchange and then re-assembling them - this reduces your speed considerably.
If so, this means the sync is higher than it really should be - and is an example of why higher sync does not always equate to higher throughput.
21CN/ADSL2+ does have a history of trying to run some lines too optimistically at a 3dB margin when they should be at 6.
Usually this problem only occurs at certain times rather than continuously.
Typical causes apart from a genuine fault on the line are:
- Increased noise on the line as evening/darkness approaches.
-  The dreaded REIN problem where someone nearby is using a defective electrical item which is dumping out Radio Frequency interference which is being picked up by your router.- and everyone else's in the neighbourhoood - 99.999% of whom will not care/notice
If you are having disconnections then that would suggest a fault - or that sometihing is dropping some really heavy RFI onto the line causing th BB signal to be temporarily obliterated.
Community Veteran
Posts: 6,735
Thanks: 12
Registered: 02-02-2008

Re: A bit of a strange one

What model of router are you using?
(I've had very similar problems as x47x described on a similar-length line. In my case resolved with some "tweaking" of interleaving to control the errors, but it's not a PN connection so they're things you maybe can't do, depending on the router)
Community Veteran
Posts: 26,638
Thanks: 869
Fixes: 10
Registered: 10-04-2007

Re: A bit of a strange one

Are you getting those speeds with a wired or a wireless connection to the router?
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)
Plusnet Help Team
Plusnet Help Team
Posts: 13,017
Thanks: 146
Fixes: 48
Registered: 27-04-2007

Re: A bit of a strange one

We'd advise raising a fault if this is still an issue.
Please give us a shout when you have
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
leejonoloughlin
Dabbler
Posts: 20
Registered: 29-12-2010

Re: A bit of a strange one

im actually using a tp link and the connection im on is wired through direct to the router , got a filtered faceplate as well. im still showing the same connection as last night and a flucuation in thourghput as normal.
ill try and grab a shot of my stats if you dont mind trawling through
Mode: ADSL_2plus
Traffic Type: ATM
Status: Up
Link Power State: L0 
 
  Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (0.1 dB): 33 326
Attenuation (0.1 dB): 205 79
Output Power (0.1 dBm): 0 128
Attainable Rate (Kbps): 23972 1156
 
  Path 0  Path 1 
  Downstream Upstream Downstream Upstream
Rate (Kbps): 20987 443 0 0
 
MSGc (# of bytes in overhead channel message): 51 12 0 0
B (# of bytes in Mux Data Frame): 249 13 0 0
M (# of Mux Data Frames in FEC Data Frame): 1 1 0 0
T (Mux Data Frames over sync bytes): 3 4 0 0
R (# of check bytes in FEC Data Frame): 0 0 0 0
S (ratio of FEC over PMD Data Frame length): 0.3806 0.9911 0.0 0.0
L (# of bits in PMD Data Frame): 5254 113 0 0
D (interleaver depth): 1 1 0 0
Delay (msec): 0.9 0.24 0.0 0.0
INP (DMT symbol): 0.0 0.0 0.0 0.0
 
Super Frames: 2664034 549141 0 0
Super Frame Errors: 0 0 0 0
RS Words: 0 0 0 0
RS Correctable Errors: 0 0 0 0
RS Uncorrectable Errors: 0 0 0 0
 
HEC Errors: 4294967289 191 0 0
OCD Errors: 18 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 2145989443 872330 0 0
Data Cells: 4699530 42930 0 0
Bit Errors: 0 0 0 0
 
Total ES: 219 0
Total SES: 0 0
Total UAS: 31 4294967267

If its the router then i think i may change as ive always had my own and it may be more reliable getting a plusnet approved one. Then again this router has one hell of alot more info than im used to with the router so im only grabbing snippets of the info i understand.
what do you guys think? or is it a line problem thats going to need a ticket?
cheers
lee
Community Veteran
Posts: 6,735
Thanks: 12
Registered: 02-02-2008

Re: A bit of a strange one

HEC errors seem to be VERY high. Possibly pointing to the problem - cause and resolution might be trickier.
I'd contact support as requested by AW.
leejonoloughlin
Dabbler
Posts: 20
Registered: 29-12-2010

Re: A bit of a strange one

Ok adam submitted a request via the broadband troubleshooter, boy is that longwinded what do hec errors point to btw?
Community Veteran
Posts: 26,638
Thanks: 869
Fixes: 10
Registered: 10-04-2007

Re: A bit of a strange one

HEC errors is strange - but doesn't look like it's a genuine high figure as it is very close to 232 - more like it's gone negative
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)
leejonoloughlin
Dabbler
Posts: 20
Registered: 29-12-2010

Re: A bit of a strange one

yeah i know what you mean as i can see test were done about 20 mins ago as the router went off/ on to adsl 1 then back to adsl 2 and it looks as if the errors are the same  good newsis the upstreams gone to only 6 errors