DLM strikes again.

Several days ago DLM decided once again that my line needed interleaving, this time at a depth of 1433. It was at the tail end of the recent storms, so may have been that or even OR working on the cab maybe disturbed my line.

My errors are not bad, I have 67 errored seconds in over 1.4 million, my other stats don't have large errors either. I wish that you could request that DLM be turned off.

Roll on the deployment of FTTPoD, that will get rid of DLM.

In reply to a post by TheHorseman:

Roll on the deployment of FTTPoD, that will get rid of DLM.

And your bank balance .

funny enough DLM doesnt want to interleave my line, I have FEC on fast path with crc errors coming in the 1000s

Below are my current stats, can anyone suggest why DLM thinks I need an interleave of 1433?

# xdslcmd info --show
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 32641 Kbps, Downstream rate = 83960 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 73187 Kbps

Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.1 15.2
Attn(dB): 14.0 0.0
Pwr(dBm): 13.1 4.3
VDSL2 framing
Bearer 0
MSGc: 18 26
B: 51 237
M: 1 1
T: 64 42
R: 12 16
S: 0.0226 0.3781
L: 22648 5374
D: 1433 1
I: 64 127
N: 64 254
Counters
Bearer 0
OHF: 1025485681 3311373
OHFErr: 520 218
RS: 531154772 2382555
RSCorr: 3208647 1567
RSUnCorr: 26739 0

Bearer 0
HEC: 6605 0
OCD: 122 0
LCD: 122 0
Total Cells: 3459140466 0
Data Cells: 616454956 0
Drop Cells: 0
Bit Errors: 0 0

ES: 107 190
SES: 0 16
UAS: 24 24
AS: 1489538

Bearer 0
INP: 3.00 0.00
INPRein: 0.00 0.00
delay: 8 0
PER: 1.45 3.98
OR: 132.18 64.22
AgR: 73319.59 20063.54

Bitswap: 1095623/1095626 51348/51498

#

you didnt show the most important info FEC/CRC/ES/SES counts.

I can't see anything obvious.

Maybe it was a reaction to 'something' that happened 17 days ago, around the time the connection resynced.

It may be worth forcing a single resync now.
I wouldn't be at all surprised if it returned to fastpath.

For FEC, read the RSCorr data.

For CRC, read the OHFErr data.

ES & SES are actually shown in the posted log data extract.

Ok, full stats:

# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 32641 Kbps, Downstream rate = 84192 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 73187 Kbps

Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.2 15.2
Attn(dB): 14.0 0.0
Pwr(dBm): 13.1 4.3
VDSL2 framing
Bearer 0
MSGc: 18 26
B: 51 237
M: 1 1
T: 64 42
R: 12 16
S: 0.0226 0.3781
L: 22648 5374
D: 1433 1
I: 64 127
N: 64 254
Counters
Bearer 0
OHF: 1030930124 1076618
OHFErr: 530 218
RS: 1924932067 134404
RSCorr: 3227369 1575
RSUnCorr: 27953 0

Bearer 0
HEC: 6936 0
OCD: 125 0
LCD: 125 0
Total Cells: 277061155 0
Data Cells: 620460008 0
Drop Cells: 0
Bit Errors: 0 0

ES: 109 190
SES: 0 16
UAS: 24 24
AS: 1497447

Bearer 0
INP: 3.00 0.00
INPRein: 0.00 0.00
delay: 8 0
PER: 1.45 3.98
OR: 132.18 64.22
AgR: 73319.59 20063.54

Bitswap: 1101655/1101657 52135/52286

Total time = 1 days 7 hours 57 min 51 sec
FEC: 3227369 1575
CRC: 530 218
ES: 109 190
SES: 0 16
UAS: 24 24
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 12 min 51 sec
FEC: 3596 0
CRC: 3 0
ES: 1 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 5603 0
CRC: 7 0
ES: 1 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 7 hours 57 min 51 sec
FEC: 220942 26
CRC: 253 5
ES: 42 5
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 172196 48
CRC: 50 11
ES: 10 9
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Since Link time = 17 days 7 hours 57 min 25 sec
FEC: 3227369 1575
CRC: 530 218
ES: 109 190
SES: 0 16
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
#

Thanks, I did not think that the errors were that bad, I will leave it over night and if there is no change I'll do a single resync and see if that changes things.

I would only do that if your SNRM from the pbParams data is showing a healthy margin above the target SNRM of 6 dB at around noon. i.e. if it shows as say 8dB or more.

Edited by deleted (Sat 30-Aug-14 23:32:03)

Give it half a minute or so between disconnection and starting up again. Sometimes the modem reconnects so quickly that the drop in the PPP session isn't noticed higher up the tree so changes aren't necessarily actioned at the ISP level.

your error rate looks a bit high to me, whether or not its high enough to keep you interleaved I am not sure tho.

When I was interleaved last time and I got reverted to fast path by DLM I was getting under 5000 FEC a day and pretty much 0 CRC.

Edited by Chrysalis (Sun 31-Aug-14 12:06:18)

In reply to a post by Chrysalis:

funny enough DLM doesnt want to interleave my line, I have FEC on fast path with crc errors coming in the 1000s

DLM intervened for me when the ES count reached around 2,500 in one day (CRC count tended to be 10x as high as the ES count)

Now my ES is in single figures per day, but DLM hasn't relented.

In reply to a post by TheHorseman:

Below are my current stats, can anyone suggest why DLM thinks I need an interleave of 1433?

It appears thar DLM watches the ES value before deciding to intervene; ES increments happen because of CRC errors.

In my case, DLM intervened when ES reached 2,500, but hadn't intervened on other days when ES reach just over 2,000.

However, looking at the current stats does not tell you why DLM intervened in the first place - it only tells you that DLM has not yet seen enough to choose to reduce the intervention.

What does it look at? This is unknown, but a good bet would be that it looks at both the ES rate and the FEC rate.

In reply to a post by WWWombat:

In reply to a post by Chrysalis:

funny enough DLM doesnt want to interleave my line, I have FEC on fast path with crc errors coming in the 1000s

DLM intervened for me when the ES count reached around 2,500 in one day (CRC count tended to be 10x as high as the ES count)

Now my ES is in single figures per day, but DLM hasn't relented.

Speak of the devil...

Last night, DLM removed the intervention. After exactly 8 weeks of intervention, speed is back to 79/20.

In reply to a post by TheHorseman:

Roll on the deployment of FTTPoD, that will get rid of DLM.

I think FTTPoD do have DLM on it the same way with FTTC. Because both are from openreach DLM system.

The more worrying aspect is if BT apply their BRAS profile like they do on FTTC and FTTP?

Is there an Openreach DLM on FTTP? I can't think what it would do.

There is bound to be the BTW IP Profile on BT Wholesale connections. There's nothing unique about FTTPoD once it gets to the exchange. Probably not after it reaches the aggregation point.

I am sure FTTC, FTTP and FTTPoD all do have DLM and Bras Profile on it.

The DLM is applied at the cabinet adslmax. FTTPoD doesn't go to the cabinet, and what would DLM manage on FTTPoD or FTTP? The sync speeds are fixed at product level.

The BT Wholesale IP Profile doesn't apply to Sky or TalkTalk FTTC. I'm not sure about all Zen FTTC.

But Sky & TalkTalk still with DLM thought.

As Roberto says fibre is a fixed speed product. DLM is only required where a product speed is variable - FTTP isn't so no DLM should be necessary. Obviously the D stands for Dynamic and there is nothing that is "dynamic" in that way with FTTP.

In reply to a post by RobertoS:

The BT Wholesale IP Profile doesn't apply to Sky or TalkTalk FTTC. I'm not sure about all Zen FTTC.

Zen buy GEA-FTTC from Openreach and connect to their own MSAN if they have presence - so there's no BT Wholesale BRAS profile as BT Wholesale are not involved. If they do not have presence, they use BT Wholesale WBMC (with a BT Wholesale BRAS Profile).

Existing customers are moved from BT Wholesale to the Zen network as the Zen network is rolled out. I was moved to the Zen network on 1 October. Zen customers can see which network they are on using the "View Line Data" option in the customer portal - it says "Your current line technology is GEA FTTC" for people on the Zen network and "Your current line technology is WBMC" for people connected via BT Wholesale.

Welcome back

Hi David.

Good to see you back . If you've been ill, I hope you are much recovered. If you just got fed up with the place, that wouldn't surprise me.

The reason I worded my post that way is that since the initial announcement of 200 or so exchanges we don't seem to have heard anything. So I had no idea how far their rollout had got.

The way the announcement read as well, it didn't sound like LLU as we know it, with MSANs. What does your exchange show on samknows for Zen Internet?

Thanks for the welcome back, Bob and BatBoy. I disappeared for a while due to commitments demanding what strength I had available. I will probably be in and out, but it's good to drop by again and see so many familiar names on screen.


Samknows doesn't show Zen as having unbundled my exchange - they're showing nothing beyond the original c. 200 exchanges. I was rather surprised to find my FTTC had switched to the Zen network, as I hadn't imagined we were on the list for Zen's roll out. Indeed, I wasn't aware that Zen were continuing to unbundle exchanges beyond the original 200.

This is an area where Virgin arrived long before any ADSL. None of neighbouring exchanges are amongst the original list of 200 where Zen have presence. As there was no Openreach GEA-FTTx on any neighbouring exchanges when this exchange was enabled, I would be surprised if the handover point was remote from the exchange. Samknows says the exchange has c. 7000 residential premises and c. 200 non-residential premises.


Zen are deploying an MPLS network. From what I understand from discussion here and on Zen's own forums, Zen's MSANs are being used to provide leased line services, as well as EFM (not sure whether they use EFM line cards in the MSAN and rent MPFs from Openreach, or rent an EFM circuit from Openreach) and services over GEA-FTTx. The MSANs are capable of ADSL2+ and voice if the appropriate line cards are fitted. I believe Zen are already providing LLU ADSL2+ using SMPF. Eventually, they will be capable of offering full LLU using MPF using this equipment.

I stress that the information in the previous paragraph is my understanding of the situation, which could be incorrect.


If the plan is indeed to offer full LLU using MPF, this would explain why Zen are so keen to sell the current FTTx products as 'voice plus broadband' bundles. It also seems that Zen's business plans involve reducing their dependence on BT Wholesale to a considerable extent.

I suspect this is partly why native IPv6 appears to be on the backburner - there are other areas of the business demanding the available engineering resources. Those of us who want IPv6 can always tunnel to SixXS or Hurricane Electric. My SixXS tunnel is capable of full 80/20 line speed.


I've finally got round to ditching BT Retail voice service. Those who recall my postings around the time of the last BT Retail price rise will remember how close I was to leaving, and the latest price rises are just too much. The voice service on the line with Zen FTTC and another line I still use with no broadband service moves to Zen next week.

Edited by deleted (Fri 24-Oct-14 22:03:19)