Will DLM apply G.INP (Downstream) to line configured as FASTPATH?

[#1]

Hi @Gandalf - looks like someone turned on interleaving downstream at about 7.30am this morning.

At first glance I'm pretty impressed!!

ES seem to have gone (I cant believe interleaving works this well!!)... I'm not getting uncorrected HEC errors, and I don't think there are any uncorrected CRC errors either... a few FEC's but nothing to worry about.

Recent 1 hour graph...

Nice sync rate and healthy looking SNRM. Obviously, a little more latency - but nothing drastic at this point.

Early tests suggest some Buffer Bloat may be back... I will look at this more closely... maybe SQM/CAKE doesn't play nice with interleaving?

Maybe all my problems were down to the old Netgear DG834 - I had it in service for a very long time... and it wasn't always surge protected - maybe it was faulty or never able to cope with ADSL2+?

Fingers crossed this holds up!

Enjoy your trip - I love the Three Valleys myself. Hope you have plenty of fresh snowfall.

[#2]

Awesome, I'm glad to see your connection's getting better with interleaving. ‌‌Keep us posted on how it goes.

Cheers, I'll be out in Les Arcs. I'm told it's forecast to snow more this weekend, so just in time!

[#3]

Weird!

TL;DR Needed a power-down/hard reset after all the server-side changes to realise any benefit.

Throughout the day I've been trying to get a download/test/anything higher than 7Mbps. But nothing doing.

I figured out that the SQM problems (the return of bufferbloat) was partly because of my highly tuned RTT setting (RTT/Ping times increased due to interleaving or course) and partly due to having a 10+Mbps sync rate but only 7Mbps throughput (despite several forced PPP reconnects).

Setting up SQM with increased latency and 7Mbps sync rate made it all work perfectly as before... but of course no increases realised here?? Roughly 5.5Mbps throughput without bufferbloat.

I decided to power off the router just to double-check before coming here to rant (I forgot to save my collectd data which lives in memory and so dies with power loss, d'oh!!).

Low and behold... raw downloads now 9Mbps... much better!

After applying an untuned SQM I can get 7+Mbps throughput without anyone on the LAN having any perceived lag/bufferbloat!!

Gaming pings looked to have increased by around 10ms before the hard reset - better than last time I was interleaved, maybe lower level interleaving so far?

The only puzzling thing is that bitswap remains disabled on upstream... is this because those frequencies are so stable there is no need for swaps? It doesn't matter - its just curious.

Now we will see the stability of the line running at its proper speeds.

Last 1 hour... ES creeping back now at proper speeds!

[#4]

Hey @Anywho,

I'm glad to see that there's been some improvement on this one. Based on what I can see at the moment I think the best course of action would be to monitor things and see how it performs from your side for the time being. If it looks like anything is slipping or there are any drops, just give us a shout and we'll be happy to pick this back up for further review

[#5]

I'm watching and learning!

I reckon the current connection is close to the best I will achieve (until I get the possible fault looked at of course - but I'm not quite ready yet!).

The connection dropped Friday morning (maybe you ran one of your tests?) during a quite noisy spell.

It returned with 9.5Mbps@10dB SNRM (strange SNRM, all DLM - I'm still not fiddling with it).

I didn't check interleaving parameters before it reset... but they are pretty high since the reset. Interleave depth of 64 with INP of 10 and delay of 8ms (though, in LOL this is nearer 20ms)... this does mean that I'm seeing very few errors.

and the last day ES...

So there is probably a little bit of room to reduce SNRM if I wanted... but I'm not gonna rush... I'm just gonna observe for a bit longer.

I was really hoping that I was right about ReTx on ADSL... but no sign of it yet

[#6]

Just a little update - NO ACTION!

So...

I got a modem with Broadcom chipset to see if it might encourage G.INP (PhyR).

I have let DLM manage my connection for the last 6 weeks or so... it has slowly increased my SNRM until it finally reached 15dB 9 days ago - at this point it also removed interleaving.

I have now been running for 9 days with a sync of (DS/US) 6.8/1.2 Mbps SNRM 15/6 dB with average DS ES < 200 per day, average DS CRC < 350 per day on FastPath.

It seems DLM is happy with this... but I am not!

By the time I apply my QoS shaping (SQM) I can almost achieve DS 4.5 Mbps throughput (no bufferbloat). With tuning I may be able to increase this closer to 5 Mbps.

This isn't quite enough.

In the coming days I'm going to try and convince the Modem to sync with 12dB SNRM and see what it does - though I'm guessing with a connection profile of "stable" making my own manual adjustments could really confuse the DLM (thinking it is working with a SNRM 15dB that is actually only 12dB will make the line appear to the DLM to be even worse than it actually is; more errors at 12dB than 15dB).

Still no sign of G.INP!

I was fairly content at my last update 9.5Mbps@10dB SNRM was pretty stable with the interleaving (though a little more lag/higher ping than is ideal - but what ya gonna do!). And this was with a Lantiq/Intel chipset... the Broadcom seems better, though I have no data to back this up.