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[guest]

Just proving that problems hit us all, I have a nasty issue with my ADSL.

Basically my sync speed hasn't changed, my error counts haven't increased but the data throughput on the line has dropped from 2MB/s to 600kB/s for no apparent reason. After an initial encounter with UKO first-line support I sidestepped them and was lucky enough to get Easynet escalations on the case - UKOnline_Dan over on TBB is a star, he really is.

Anyway here's the text from the latest email, just in case any of you can work out what is occurring :

I just capped your line at 16Mbit to experiment, and something odd
happened...

At 19Mbit, with a 29 hour uptime:

noise-margin-down = 7
attenuation-down = 23
output-power-down = 20
noise-margin-up = 7
attenuation-up = 13
output-power-up = 12
near-end-fec = 903
near-end-crc = 26
near-end-hec = 51
far-end-fec = 44318
far-end-crc = 716
far-end-hec = 1609

Now, at 16Mbit with a few minutes uptime:

noise-margin-down = 7
attenuation-down = 23
output-power-down = 20
noise-margin-up = 7
attenuation-up = 13
output-power-up = 12
near-end-fec = 10
near-end-crc = 0
near-end-hec = 0
far-end-fec = 14092
far-end-crc = 161
far-end-hec = 1261

Two things stick out there to me.  The SNR should have gone up with the
lower sync speed, and it started at only 5dB.  And, that's a fairly
consistant amount of far-end errors creeping in which makes me suspect
the router may have issues.  Either that, or you're getting some local
interferance on the line.

I think it must be the router as there's no way there's additional local noise at 2pm. Evening/night yes, but afternoon? Either that or its the line card.

So the plan is to visit PC World and "borrow" one of their routers (borrow = buy then return if it doesn't help).

Damn strange fault if you ask me.

Aside to kitz - looks like capping the line is done by increasing interleave depth from 64 to 256.

[Azzaka]

hey o Rizla,

When did this problem start? and havr oyu tried an ADSL Max profile instead of a 2+ Profile.

Leo

[guest]

Hi Leo. To be honest I haven't a clue when it started (been working 80+ hour weeks lately) but in the last month for sure.

Its a LLU connection mate so an ADSL Max profile isn't going to help. I can set the noise margin (and hence sync speed) to anything I want via DMT Tool but frankly it doesn't make a lot of difference to throughput speed or errors. If you mean switch it to ADSL1 or 2 rather than 2+ then that's an idea I guess, although what it'd prove I dunno as I'm getting burst speeds of 10Mbps this morning.

If the Netgear had enough memory to display the bits per tone then all might become clear(er) but it doesn't so that leaves me with the unpalatable option of flashing the BeBox (ST780WL) with whatever firmware is (a) available and (b) works with DMT Tool.

Getting an identical router is really the only way to go I feel. If that does the same with the mains power off in the house (router on UPS) then I'll push for a lift and shift to another port/card.

I don't have the time for this Thank gods that Dan offered to help

[Azzaka]

G'day Rizla,

ok yes it is worth changing to DSLMax ADSL1 profile from 2+ as it could stablise. You will lose speed however. I had the same issue. On a 2+ profile I got 5mb, on a dsl max profile i am getting 7mb, go figure.

The 780wl is what i use and can help although the Netgear DG834Gv3 i still stand by with the upgraded firmware. Let me know how you.

PS: I appologise for my terrible spelling last night. Long day.

[guest]

Well its not a problem at my end, I'm now convinced of that. New DG834GT running on UPS, line is perfect, throughput is rubbish.

The new DG834GT has a shell which works  so you can actually check the bitloading and track it over time. Suffice it to say that there's not a lot of bitswapping going on and there's plenty of half-empty bins (connection is currently capped at 16/1Mbps). No noise, no errors, its not me and there's nothing further I can do.

Hopefully a lift and shift is possible. Lets see....

[kitz]

>> Aside to kitz - looks like capping the line is done by increasing interleave depth from 64 to 256.

Hmmm  interesting way of doing it...  not good if youre a gamer. In fact thinking about it.. very strange.
- Increase the interleave depth to increase the overheads so actual throughput is less. 

Im not sure if UKO do this, but with BT and also with Be.. it would seem that sync makes an adjustment to allow for these overheads. 
Certainly BT with the IP profile.. and it also explains why those on Be non-interleaved can sync much higher than interleaved... and if this is the case it could very possibly explain why capping by interleaving depth isnt making much difference on your line when it comes to the SNRM.
I would however though expect the CRC/HECs to be reduced.

[guest]

Well I think the line is the same as it always has been kitz. Now I can see the bit loading it looks the same as it did on Be (but without the missing tones) 

See what you think :

Counters        Down            Up

SF:             975562          922108
SFErr:          56              31
RS:             784352246               3276894
RSCorr:         57839           244
RSUnCorr:       1399            0

HEC:            42              76
OCD:            1               0
LCD:            0               0
Total Cells:    605524869               43602298
Data Cells:     11312261                538733
Drop Cells:     0
Bit Errors:     0               0

ES:             34              13
SES:            0               0
UAS:            19              22
AS:             15677

INP:            2.50            1.72
PER:            16.08           17.93
delay:          6.40            7.75
OR:             33.33           33.00

Bitswap:        1522            377


Total time = 4hours 21min 43sec
SF  = 975562   CRC = 56
LOS = 0   LOF = 0   ES = 34

Latest 1 day time = 4hours 21min 43sec
SF  = 975562   CRC = 56
LOS = 0   LOF = 0   ES = 34

Previous 1 day time = 0sec
SF  = 0   CRC = 0
LOS = 0   LOF = 0   ES = 0

The error seconds are (I think) mainly due to me switching the power on/off at the fusebox.  Even if they're not, I can't see anything there that would reduce throughput from 16Mbps to (almost exactly) 8Mbps. Can you?

Re interleaving : gods know now as I have an interleave depth of 320 but the RCO is still reporting 19-22Mbps

More stats spam :

adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 0
Channel: FAST, Upstream rate = 1023 Kbps, Downstream rate = 16366 Kbps
Link Power State: L0
Mode:                   ADSL2+
Channel:                Fast
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):       6.1             7.5
Attn(dB):       23.0            13.0
Pwr(dBm):       7.0             12.8
Max(Kbps):      19356           1188
Rate (Kbps):    16366           1023
                        G.dmt framing
K:              41(0)           32
R:              10              16
S:              1               4
D:              64              8
                        ADSL2 framing
MSGc:           61              68
B:              40              31
M:              1               4
T:              12              1
R:              10              16
S:              0.0800          3.8787
L:              5100            297
D:              320             8
                        Counters
SF:             988598          934438
SFErr:          56              31
RS:             794833596               3492997
RSCorr:         58752           248
RSUnCorr:       1399            0

HEC:            42              76
OCD:            1               0
LCD:            0               0
Total Cells:    613619391               44365299
Data Cells:     11320047                542653
Drop Cells:     0
Bit Errors:     0               0

ES:             34              13
SES:            0               0
UAS:            19              22
AS:             15887

INP:            2.50            1.72
PER:            16.08           17.93
delay:          6.40            7.75
OR:             33.33           33.00

Bitswap:        1539            382

Total time = 4 hours 25 min 13 sec
SF  = 988598
CRC = 56
LOS = 0
LOF = 0
ES  = 34
Latest 1 day time = 4 hours 25 min 13 sec
SF  = 988598
CRC = 56
LOS = 0
LOF = 0
ES  = 34
Latest 15 minutes time = 10 min 13 sec
SF  = 38173
CRC = 3
LOS = 0
LOF = 0
ES  = 2
Previous 15 minutes time = 15 min 0 sec
SF  = 55973
CRC = 4
LOS = 0
LOF = 0
ES  = 2
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  = 56035
CRC = 4
LOS = 0
LOF = 0
ES  = 2
15 minutes interval [-45 min to -30 min] time = 15 min 0 sec
SF  = 55973
CRC = 3
LOS = 0
LOF = 0
ES  = 3
15 minutes interval [-60 min to -45 min] time = 15 min 0 sec
SF  = 55973
CRC = 5
LOS = 0
LOF = 0
ES  = 3
Showtime Drop Reason:   0
Last Retrain Reason:    0
#

[kitz]

The UAS are a lil bit higher than I would expect compared to the other errors..  but could l be a symptom if you switched off at the mains, rather than an accumulation through the "normal" error state and event process, but nothing that Id be concerned about. I cant see anything in those stats that gives any clues.  Your FECs are racking up - but didnt they always.. and its why you didnt want to go on the UKO fast trial?

Is this slower speed 24/7?

The more I think about it and if what you say about UKO capping the line simply by increasing the interleave depth, then it wont make a jolt of difference..  since the Error Correction overhead will still be there.
If you think about it the error correction overhead is an artificial limitation for the sync speed.  eg my line on be will sync as near damn it the full 24Mb in FAST mode, but with interleaving applied I lose 3.5MB of sync speed.  Therefore your SNRM wont change at all.

Is there anyway they can cap your speed other than by increasing the Interleave... eg doing it at the ISP level rather than at the dslam...  THEN I'd expect the SNRM to increase.
How about trying to rate limit your line by switching to adsl2.

Youve already done a lot of the normal troubleshooting process and it certainly doesnt appear to be your end.

I dunno..  I either suspect contention.. or like youve already mentioned - the line card.
Whats your latency like - obviously its going to be higher because of the increased Interleaving.. but anything that looks like theres a bottle neck at peak?


----

PS unrelated nit-picking - Whats this
>> Channel:                Fast
Youre obviously not because
>> D:              320             8

[guest]

The slower speed is 24/7 and any protocol/location you choose. I had zero errors at one point on Friday and no change, still 8Mbps so the errors business is completely specious I reckon.

Yeah I noticed that about the channel state - maybe 256 is the most that the Netgear can "count" so an interleave depth of 320 confuses it?

I'm not concerned about the FECs - I've had them since day 1 on UKO and they are, after all corrected errors. I was on fastpath with Be so if there had been significant error problems then it would have shown up for sure back then. Had Be used SRA then I wouldn't have tweaked the noise margin at all, but I'm sure you remember me showing you the stats of the connection running at 24Mbps on a 1.5dB margin

We'll see what happens but if 8Mbps throughput is the max now then I may as well downgrade to Sky's 8Mbps fiver a month account. The hours I'm working right now mean I have no time for this anyway, so might as well save £20/month if UKO can't/won't fix it.

Edit for latency :

Tracing route to newswww.bbc.net.uk [212.58.226.73]
over a maximum of 30 hops:

  1     1 ms     1 ms    <1 ms  server-a.homelan.local [192.168.0.1]
  2     1 ms     1 ms     1 ms  router.homelan.unsafe [192.168.10.2]
  3    34 ms    33 ms    32 ms  ip-87-82-61-208.easynet.co.uk [87.82.61.208]
  4    38 ms    40 ms    39 ms  te0-0-0.er101.bllon.uk.easynet.net [87.86.72.19]

  5    40 ms    39 ms    39 ms  ip-89-200-132-53.ov.easynet.net [89.200.132.53]

  6    43 ms    41 ms    41 ms  212.58.238.190
  7    46 ms    39 ms    38 ms  212.58.238.189
  8    41 ms    41 ms    41 ms  212.58.238.153
  9    41 ms    41 ms    41 ms  212.58.239.62
 10    42 ms    41 ms    41 ms  newslb305.telhc.bbc.co.uk [212.58.226.73]

Trace complete.

[kitz]

>> The slower speed is 24/7 and any protocol/location you choose.

Doesnt sound like contention then, more like something limiting to 8Mb somewhere isp/dslam.

>> so an interleave depth of 320 confuses it?

Possibly - Ive never seen 320 depth before though.

>> I've had them since day 1 on UKO and they are, after all corrected errors.

Yes, hence why I wasnt too concerned and I recalled you once saying that due to the high FECs that no way would you go on fast...  so hence nothing appears to have changed there either.

>> Edit for latency :

Looks fine - in fact pretty damn good if you are running at 320. 
Cant remember the depth of interleaving sky use, but sky default interleaving profile takes it up to the 90ms from up here. (-vs 14ms on Be or IPStream FAST)

>> but if 8Mbps throughput is the max

Somethings obviously wrong somewhere..

>> so might as well save £20/month if UKO can't/won't fix it

May as well 




------------------------------------

>> you the stats of the connection running at 24Mbps on a 1.5dB margin

Thats on Annex M -
Annex A can get 24Mbps on 3db profile.
When they first put me on Annex M, they inadvertantly switched interleaving back on by mistake and my max sync was around the 18,800 mark.  When they switched it off I got 22964 - both at the 3dB profile, which is where I got the 3.5Mb overhead difference from.
I then later DMT tweaked it, and it ran at 24Mb for several weeks quite happily on Annex M with a 1.5dB SNR. 
When I first went live at the 6dB profile on Annex A, removing interleaving also gave me an additional circa 3Mbps.


Something happened in July and my SNRM (and tx power) have dropped over the past couple of months.. me wonders if it something to do with more users on the dslam?  but my sync speeds now arent as good as when I first went live, and I seem to be on a downward trend   iirc mr_chris has seen similar on his line too.
But I'm not really moaning about it cause I know Im damn lucky compared to others.

[guest]

Dan is arranging a lift & shift as we speak - same DSLAM but an empty line card. Can't ask for more than that

Fingers crossed.......

[guest]

Resolved. I now have a sync speed of 19Mbps down and 1Mbps up with throughput speeds to match.



I don't yet know what the problem was but hopefully Dan can give me a bit more info.

/happy bunny mode on

[kitz]

>> Dan is arranging a lift & shift as we speak - same DSLAM but an empty line card.

YAY


>> Resolved. I now have a sync speed of 19Mbps down and 1Mbps up with throughput speeds to match.

Fantastic news

* kitz does the happy dance

>> I don't yet know what the problem was but hopefully Dan can give me a bit more info.

Yes hopefully - would be interesting to know.
although I think both you and me suspected that the line card on the dslam was a strong possibility.

[guest]

although I think both you and me suspected that the line card on the dslam was a strong possibility.

Well we were both wrong

[kitz]

Glad you got it sorted rizla