Interleave Depth

Hi!

I've had issues with my line recently with noise which caused sync issues on the router. This has now been fixed by Openreach but as you might have guessed this caused DLM to go nuts to try and stabilise the line!

Here are my line stats

DSL synchronization status:
Up
Connection status:
Showtime
Upstream line rate (kbit/s):
7537
Downstream line rate (kbit/s):
31076
Maximum upstream rate (kbit/s):
7358
Maximum downstream rate (kbit/s):
42672
Upstream noise safety coefficient (dB):
4.8
Downstream noise safety coefficient (dB):
3.8
Upstream interleave depth:
1
Downstream interleave depth:
1810
Line standard:
VDSL2
Upstream line attenuation (dB):
8.2
Downstream line attenuation (dB):
19.7
Upstream output power (dBm):
3.3
Downstream output power (dBm):
13.4
Channel type:
Interleaved

My question is this, Over the last week there have been a couple of DLM managed resets early morning which seems to be normal and each time the Interleaving depth has been reduced. So I guess i'm answering my own question but the fact that the interleaving depth is being reduced means that the line conditions are recovering as far as DLM is concerned and then it will hopefully start increasing the bandwdith?

In reply to a post by bewA:

My question is this, Over the last week there have been a couple of DLM managed resets early morning which seems to be normal and each time the Interleaving depth has been reduced. So I guess i'm answering my own question but the fact that the interleaving depth is being reduced means that the line conditions are recovering as far as DLM is concerned and then it will hopefully start increasing the bandwdith?

Yes, indeed.

Although the interleaving may be being reduced, until it is removed altogether you will suffer a loss of 6-10Mbps downstream sync, with the "Max" figure higher than it would be on Fast Path.

You haven't posted any error stats, but I suspect you are tweaking the noise margin for higher speed. As DLM's main interest is the error rates, I suggest that if I am right you revert to the DLM-set noise margin. This will reduce your sync, but also your error rate. Leading to an earlier removal of interleaving.

It's even possible that while you are tweaking the error rates are high enough to keep it on interleaved. Once it has gone, with luck you can tweak again without triggering it.

Hi RobertoS!

I'm not tweaking any SNR stuff! In fact i don't even think i can with the TalkTalk "superrouter".
I do have a Billion 8800NL but with recent problems i went back to the TalkTalk router so they couldn't blame me for messing with stuff or not using their supplied/testing hardware etc!

Plus although i understand small amount about SNR tweaking but not enough to be confident i'm not going to upset DLM!
I'll post the stats from a different screen tonight as i think there is error information there!

about going back to fastpath, i was under the impression from reading something recently (not sure where) that once you are on an interleaved profile it will never go back to fastpath? I guess that's not the case then?

It was true on BT Wholesale ADSLx that the BTW DLM never turned interleaving off automatically once it had turned it on, (I think I have seen one person say it did on their connection), but on the Openreach FTTC DLM it does. Some users have (or had) it flip-flopping every few weeks. Their lines must be on the borderline.

Re the tweaking, I suspected it because of this line:- "Downstream noise safety coefficient (dB): 3.8".

That's a very low noise margin for FTTC. I don't recall seeing any un-tweaked even as low as 5dB. As you aren't tweaking it looks to me as if you do have a fair source of noise still affecting it.

well i do have a Openreach Mk3 so maybe i'll whip that off and use the microfilter that came with the "superrouter"!

I'm just nervous about messing with stuff

The Mk3 should be better than a router-included dangly, but of course may be faulty. I assume you are connecting direct to the Mk2, not at an extension.

Also, how long is the cabling from your router to the Mk3?

The router is connected directly with the supplied RJ11 cable which is about 1mtr i guess.
I have no extensions off my socket either (hardwired or otherwise).

Looks like the connection was reset while i was at work today. Here's the latest "stats" from the router...

DSL synchronization status:
Up
Connection status:
Showtime
Upstream line rate (kbit/s):
7030
Downstream line rate (kbit/s):
28670
Maximum upstream rate (kbit/s):
7030
Maximum downstream rate (kbit/s):
39316
Upstream noise safety coefficient (dB):
6.1
Downstream noise safety coefficient (dB):
5.6
Upstream interleave depth:
1
Downstream interleave depth:
1663
Line standard:
VDSL2
Upstream line attenuation (dB):
8.2
Downstream line attenuation (dB):
19.7
Upstream output power (dBm):
3.5
Downstream output power (dBm):
13.4
Channel type:
Interleaved
DSL up-time:
0 days 9 hours 59 minutes 46 seconds

Well i've just dumped the Mk3 and gone back to the dongle and plugged directly into the test socket and things not much different!

DSL synchronization status:
Up
Connection status:
Showtime
Upstream line rate (kbit/s):
7030
Downstream line rate (kbit/s):
27848
Maximum upstream rate (kbit/s):
7030
Maximum downstream rate (kbit/s):
38304
Upstream noise safety coefficient (dB):
5.9
Downstream noise safety coefficient (dB):
6
Upstream interleave depth:
1
Downstream interleave depth:
1613
Line standard:
VDSL2
Upstream line attenuation (dB):
8.2
Downstream line attenuation (dB):
19.7
Upstream output power (dBm):
3.3
Downstream output power (dBm):
13.4
Channel type:
Interleaved
DSL up-time:
0 days 0 hours 3 minutes 19 seconds

I don't get it, things were so great when it first started, i was getting 40mbps down on fastpath and since then it's been getting progressively worse

Those two sets look right now regarding the noise margin, but decidedly ropey wrt the downstream connection speed. I used to get over 50Mbps on the same attenuation, 19.7dB, and not long ago something happened on the line and now I get 60Mbps.

Bearer: 0, Upstream rate = 15142 Kbps, Downstream rate = 59997 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 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): 5.5 6.0
Attn(dB): 19.7 0.0
Pwr(dBm): 13.6 7.5

Edited by RobertoS (Thu 05-Nov-15 19:41:51)