IP and actual speed?

[#1]

Evening all
I still find it hard to understand why the measured speed always seems so low relative to the IP.
BT tester says IP 3.35, PlusNet 3.3 which tallies(???) now I am sync'ed at 3801 (see RouterStats info below) so the IP as 88.2% is right but even when I was sync'ed lower my measured speed was also as now 3Mbps.............just my logically view that the measured speed was closer to the IP was "right" 
Now RouterStats says this
Noise Margin:    2.8  dB
Connection Rate:  3801  Kbps
Line Attenuation: 55.5  dB
Power:            0.0  dBm
Max Rate:        4584  Kbps

SuperFrames:      89781529
SF (CRC) Errors:  23716
Reed Solomon:    1630613648
RS Corrected:    162384438
RS Un-Corrected:  86377
HEC:              13997
Errored Seconds:  76238
Severe ES:        42
Interleave Depth: 32
Bitswaps:        249424
But note the uptime info
Total Uptimes (From SF counts):
WAN:  17 days, 16:03:18
LAN:  25 days, 17:30:12


CRC:  145112
LOS:  2
LOF:  18
ES :  76259
This is for one continuous PPPoA session and frankly I was surprised at how well the 3db Margin connection has held as my "normal" is 6db
TIA for the qualified feedback (again?) 

[#2]

There's a lot of ES errors as well as some SES never mind the LOF & LOS so there will probably have been a lot of data retransmitted which has the effect of a slowdown in throughput. If DLM has put the Target SNRM down to 3dB and it doesn't like the error rate it'll no doubt put it back to 6dB.

[#3]

Hi Anotherone
Yes, I was surprised at the errors rate for such a sustained perioed @ 3db margin....................almost like the DLM is holding like grim death 
But I take your point that is the system is accomodating a high rate of retransmission there will be measured speed loss(es) ~ correct ?
Having said that I am now wondering if I should drop the session and reboot the router to see what it "decides" to sync at and with what margin i.e. not just start a new session???
Might do that over the weekend during daylight hours 

[#4]

I'd be tempted to reconnect in the evening to raise the margin a bit and reduce the errors, you might get a better 'real speed' that way (and less chance of drops).

[#5]

Yes, correct, high retransmission rate will give a measured speed loss, as well as possibly adding in some lag.
Whilst walker23's suggestion is certainly worth consideration, it depends a bit on how much your margin typically drops after dark but also how much variability there is after dark, only you can judge that from your knowledge of your own line. It could be a case of suck and see, at least you aren't hampered by profile bands, being on 21CN.
I guess, from the way you described dropping the session before powering down, you are familiar with that method that should mean DLM doesn't see the loss of sync as a line problem. I always recommend wait a minute or two before powering down after dropping the session and then stay off for about 10 minutes before powering up. That way should you encounter any issues, it's clear on the Radius log that there was a defined break and not just a drop that could be wrongly be interpreted as a loss of sync. Of course the odd instantaneous power up again shouldn't be a problem.

[#6]

Hi both
Thanks for the insight(s).
As for the margin over the 24 hours period I do not recall seeing much variation between day & night time periods..............for example it now 2.6db  and when I was more 'normally' at 6db the range was between 5.8 to 6.5 but for the life of me I could not tell you the day/night periodicity without digging through thr RouterStats logs???
So because history has been so little apparent daily variance and now 21CN I could do it anytime like shortly/now???
Will report back as appropriate 

[#7]

Right here are the RouterStats figures having mad a fresh connection after a Routerr reboot.
DL
Noise Margin:    2.9  dB
Connection Rate:  3755  Kbps
Line Attenuation: 56.0  dB
Power:            0.0  dBm
Max Rate:        4708  Kbps

SuperFrames:      18757
SF (CRC) Errors:  2
Reed Solomon:    609608
RS Corrected:    33472
RS Un-Corrected:  17
HEC:              2
Errored Seconds:  1
Severe ES:        0
Interleave Depth: 16
Bitswaps:        42
UL
Noise Margin:    19.1  dB
Connection Rate:  444  Kbps
Line Attenuation: 29.3  dB
Power:            12.8  dBm
Max Rate:        860  Kbps

SuperFrames:      20506
SF (CRC) Errors:  0
Reed Solomon:    0
RS Corrected:    0
RS Un-Corrected:  0
HEC:              0
Errored Seconds:  0
Severe ES:        0
Interleave Depth: 1
Bitswaps:        20

Total Uptimes (From SF counts):
WAN:  0 days, 00:06:27
LAN:  0 days, 00:06:27


CRC:  2
LOS:  0
LOF:  0
ES :  1
Note the Interleave depth on the DL has dropped from 32 to 16

[#8]

It obviously thinks your errors are low enough  and it looks like you are stuck with that superfast sync speed and a 0.1db improvement in Noise Margin 
But the real test is what does the BT speedtester say? About 3Mbps if you're lucky.

[#9]

BT Speedtester says :-
IP 3.31Mbps
Measured Speed 2.97Mbps
So not withstanding the time of the day the measured speed is poorer compared when noted in my OP, though not by much mind 
I wonder if I should ask for a margin reset to 6db as I was getting a sync of I think approx 3500 and measured speed of about 3.1 consistently or better at that margin.....................even 21CN DLM has its oddities!

[#10]

It could be a Gateway thing or a BT speedtester thing, one instantaneous result might not be that representative. See how it goes over a few days, try a couple of speedtesters, the BT beta gives a more optimistic result, TBB is pretty reliable and mybroadbandspeed (when not under heavy load!).
If things don't seem too clever try a Gateway hop.
If the level of errors continues to be very high, I'd be looking for other possible problems.

[#11]

Updated info
RouterStats data
DL
Noise Margin:     3.6   dB
Connection Rate:  3755  Kbps
Line Attenuation: 56.0  dB
Power:            0.0   dBm
Max Rate:         4740  Kbps

SuperFrames:      16654160
SF (CRC) Errors:  1203
Reed Solomon:     541260214
RS Corrected:     16345490
RS Un-Corrected:  13628
HEC:              1128
Errored Seconds:  436
Severe ES:        5
Interleave Depth: 16
Bitswaps:         10818

UL
Noise Margin:     18.7  dB
Connection Rate:  444   Kbps
Line Attenuation: 29.3  dB
Power:            12.8  dBm
Max Rate:         784   Kbps

SuperFrames:      14992508
SF (CRC) Errors:  0
Reed Solomon:     0
RS Corrected:     0
RS Un-Corrected:  0
HEC:              0
Errored Seconds:  0
Severe ES:        0
Interleave Depth: 1
Bitswaps:         10351

Uptime info
Total Uptimes (From SF counts):
WAN:   3 days, 06:39:43
LAN:   3 days, 06:39:43


CRC:  1203
LOS:  0
LOF:  0
ES :  436

As you can see the Margin is 3.6 an indeed does seem to be that sort of >3.0db comapred to before I rebooted the Router
Now granted no always the best time of day for a speedtest but here a one off TBB one:-

So still on the face of it running kind of slow for the Sync speed!
PS Did the BT ones
The beta speed test :-
DL 3.11Mbps
UL 0.35Mbps
Ping 41ms
Older ADSL test
DL 2.98Mbps
UL 0.37Mbps
IP 3.31

[#12]

Could you check your Current Line speed (Login required)
also the VP status of your Exchange here.
Check which Gateway you are on
If the first two are OK you could try a Gateway hop. Do a Disconnect of your PPP Internet session with the ISP - you need to login to the modem/router interface and look for the Disconnect button to click on, give it a few seconds and then click Connect.
Check your Gateway again. and then see if a speedtest is any different.

[#13]

Hi
In answer to the first two queries:-
IP at PlusNet towers is 3.3Mbps (so tallies with the BT reading)
An the exchnage shows as VP Green with no known issues
Will try a Gateway hop tomorrow during daylight hours and see what that shows then but current Gateway is ptn-ag01

[#14]

Did a Gateway hop a minutes ago but oddly the "tool" has yet to ID the Gateway....................though reassuringly the dialogue tells me not to worry as nothing is wrong  
30+ mins on and the Gateway Tool is still not able to tell which one I am connected to???

[#15]

Hi, you're on ptw-ag03