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ADSL2+ 21CN performance on loooooong lines....

ashgeo
Grafter
Posts: 96
Registered: ‎24-07-2008

ADSL2+ 21CN performance on loooooong lines....

For those that may be interested in how ADSL2+ performs on long lines.....
Prior to moving to ADSL2+ I was syncing between 800 & 950kbps on a 750k profile on DSL MAX and now after about a month on ADSL2+ I am syncing at 1472 Kbps down and 395Kbps up, with a 3dB SNR down and 8dB up. My line attenuation is 76.5dB which equates to roughly a 7-8Km line. Over the past week or so the DLM seems to have settled on a 3dB SNR and is happy with it!  I have a NetGear DGN2000 with the latest  firmware and am using a BT iPlate.  I've also got rid of anything in the house causing interference, e.g. CFL Lamps!  I think the convoluted route the line takes from the exchange is mostly underground.  I now have at last got a 1meg profile  Cheesy
If anyone out there is considering switching to ADSL2+ with a long line I would say go for it as it seems to squeeze an small but significant increase in line speed.
Below are the stats and the bits/tones/SNR graphs from my router (via routerstats):
/usr/sbin/adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 1
Channel: FAST, Upstream rate = 395 Kbps, Downstream rate = 1472 Kbps
Link Power State: L0
Mode:                  ADSL2+    <--Please note ADSL2+ and not ADSL2 Cool
Channel:                Fast
Trellis:                U:ON /D:ON
Line Status:            No Defect

Training Status:        Showtime
                Down            Up
SNR (dB):      2.9            8.0
Attn(dB):      76.5            44.4
Pwr(dBm):      15.9            11.6
Max(Kbps):      1920            13901
Rate (Kbps):    1472            395
                        G.dmt framing
K:              52(0)          20
R:              12              8
S:              4              2
😧              4              4
                        ADSL2 framing
MSGc:          52              19
B:              51              19
M:              4              2
T:              1              4
R:              12              8
S:              4.4332          3.2000
L:              397            120
😧              4              4
                        Counters
SF:            13801311                5544884
SFErr:          6731            92939
RS:            200119024              2366318
RSCorr:        929127          7381851
RSUnCorr:      40876          0
HEC:            4964            45630
OCD:            426            0
LCD:            2              0
Total Cells:    770194606              2674149076
Data Cells:    3323805        132624473
Drop Cells:    0
Bit Errors:    0              3977111
ES:            3692            52945
SES:            78              926
UAS:            107            524649
AS:            221796
INP:            0.48            1.06
PER:            16.07          40.00
delay:          4.43            3.20
OR:            28.87          5.00
Bitswap:        24484          467
Total time = 1 days 16 hours 17 min 46 sec
SF  = 19761968
CRC = 10823
LOS = 55
LOF = 41
ES  = 3692
Latest 1 day time = 16 hours 17 min 46 sec
SF  = 3650500
CRC = 1819
LOS = 14
LOF = 3
ES  = 750
Latest 15 minutes time = 2 min 46 sec
SF  = 10360
CRC = 0
LOS = 0
LOF = 0
ES  = 0
Previous 15 minutes time = 15 min 0 sec
SF  = 55984
CRC = 11
LOS = 0
LOF = 0
ES  = 9
Previous 1 day time = 24 hours 0 sec
SF  = 5376327
CRC = 2481
LOS = 7
LOF = 1
ES  = 1041
15 minutes interval [-30 min to -15 min] time = 15 min 0 sec
SF  = 55984
CRC = 8
LOS = 0
LOF = 0
ES  = 7
15 minutes interval [-45 min to -30 min] time = 15 min 0 sec
SF  = 56046
CRC = 5
LOS = 0
LOF = 0
ES  = 5
15 minutes interval [-60 min to -45 min] time = 15 min 0 sec
SF  = 55984
CRC = 14
LOS = 0
LOF = 0
ES  = 11
Showtime Drop Reason:  1
Last Retrain Reason:    1
6 REPLIES 6
scootie
Grafter
Posts: 4,799
Thanks: 1
Registered: ‎03-11-2007

Re: ADSL2+ 21CN performance on loooooong lines....

adsl2+ and fastpath at that line length and the DLM hasnt gone nuts. have you faked the stats as a joke  Grin
ive never seen the dlm allow the + on such a long line.
Am on 50db atten and it dont let me, even if i try and force the stuborn DLM
ashgeo
Grafter
Posts: 96
Registered: ‎24-07-2008

Re: ADSL2+ 21CN performance on loooooong lines....

@ ASBO DOG
I promise nothing is faked here. I am as astounded as you are (having beeen tracking this forum for a long time). I have also had none of the other problems that have been reported here as yet, and long may it last. I now have the fastest connection I have ever had, it's now almost broadband Grin
To prove it is not fake, here are this morning's stats (after switching router off all night):
usr/sbin/adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 0
Channel: FAST, Upstream rate = 335 Kbps, Downstream rate = 1474 Kbps
Link Power State: L0
Mode:                  ADSL2+
Channel:                Fast
Trellis:                U:OFF /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):      3.3            7.6
Attn(dB):      76.5            44.5
Pwr(dBm):      15.8            11.6
Max(Kbps):      1452            11916  <--This must be a software glitch!
Rate (Kbps):    1474            335
                        G.dmt framing
K:              53(0)          17
R:              8              16
S:              4              4
😧              4              2
                        ADSL2 framing
MSGc:          51              19
B:              52              16
M:              4              4
T:              1              4
R:              8              16
S:              4.5128          6.4000
L:              390            105
😧              4              2
                        Counters
SF:            540400          217175
SFErr:          79              93237
RS:            7700708        1134420
RSCorr:        12618          7381940
RSUnCorr:      297            0
HEC:            49              45638
OCD:            4              0
LCD:            0              0
Total Cells:    30222048                2682279877
Data Cells:    445836          132707395
Drop Cells:    0
Bit Errors:    0              3977119
ES:            62              52957
SES:            1              938
UAS:            24              548624
AS:            8688
INP:            0.32            1.21
PER:            16.07          40.00
delay:          4.51            3.20
OR:            28.36          5.00
Bitswap:        224            15
Total time = 2 hours 25 min 23 sec
SF  = 540400
CRC = 79
LOS = 1
LOF = 0
ES  = 62
Latest 1 day time = 2 hours 25 min 23 sec
SF  = 540400
CRC = 79
LOS = 1
LOF = 0
ES  = 62
Latest 15 minutes time = 10 min 23 sec
SF  = 38805
CRC = 7
LOS = 0
LOF = 0
ES  = 6
Previous 15 minutes time = 15 min 0 sec
SF  = 55962
CRC = 10
LOS = 0
LOF = 0
ES  = 9
Previous 1 day time = 0 sec
SF  = 0
CRC = 0
LOS = 0
LOF = 0
ES  = 0
15 minutes interval [-30 min to -15 min] time = 15 min 0 sec
SF  = 56024
CRC = 12
LOS = 0
LOF = 0
ES  = 11
15 minutes interval [-45 min to -30 min] time = 15 min 0 sec
SF  = 55899
CRC = 5
LOS = 0
LOF = 0
ES  = 4
15 minutes interval [-60 min to -45 min] time = 15 min 0 sec
SF  = 56024
CRC = 1
LOS = 0
LOF = 0
ES  = 1
Showtime Drop Reason:  0
Last Retrain Reason:    0
James
Grafter
Posts: 21,036
Thanks: 5
Registered: ‎04-04-2007

Re:ADSL2+ 21CN performance on loooooong lines....

Hi Ashgeo,
I'm also quite surprised - certainly wouldn't expect you to be seeing ADSL2+ given your line length!
Your line length is enormous!  What sort of speeds did you get before ADSL2?  Better or worse?
ashgeo
Grafter
Posts: 96
Registered: ‎24-07-2008

Re: ADSL2+ 21CN performance on loooooong lines....

@ James:
Before migrating onto 21CN and ADSL2+ I was experiencing problems with the line on DSLmax with the router syncing downstream lower than the upstream when it was at it's worse, but after intervention from PN via a ticket to BT the sync rate gradually increased to anywhere between 600-950kbps, most of the time in the range of 800-950kbps. Since migrating I have seen a dramatic but small increase in my sync speed to where we are today at around 1400kbps.  This new rate has pushed my IP profile from 500 to 750 and now the illusive 1meg (almost broadband) Cheesy
I have not had (as yet) any of the other problems that have been spoken about at length on this forum and my router always seems to sync on the ADSL2+ mode and not ADSL2.....  The line performance has suprised me considering the attenuation. The DLM seems to be happy with the 4-5dB SNR as well. Maybe when BT switched over the Ashford (Kent) exchange earlier this year they installed a "new improved" version of the DLM? Even ASBO DOG has been suprised!
Attached is the router stats page from this afternoon. Router is also still synced on ADSL2+......!!
Regards,
George
ashgeo
Grafter
Posts: 96
Registered: ‎24-07-2008

Re: ADSL2+ 21CN performance on loooooong lines....

For those that are still interested in ADSL 2+ and perfomance on long lines.....
I still have an attenuation of 76.0dB with an estimated line length of 7Km plus.  My sync rate has been fairly consistent since switching from DSL MAX and have now got an IP Profile of 1250Kbps! Attached is a graph of the results from mybroadbandspeed which shows the increase when I switched over to ADSL2+ mid October.  The router seems to be quite happy with an SNR of around 3dB.
From my persepctive it has been well worth switching and I have seen an increase in line speed of over 100% since changing. I have experienced none of the problems that most folks seem to be posting in this forum so for me it has been a positive experience    Cheesy
Mand
Grafter
Posts: 5,560
Thanks: 2
Registered: ‎05-04-2007

Re: ADSL2+ 21CN performance on loooooong lines....

Thanks for the update, glad to hear things are still going well.