First three days on TTR: Pretty good

I've left Plusnet Business this week, for TalkTalk (retail).

I was sorry to leave PN, but the ongoing issues with BTW's vlan management, and the lack of workable VDSL2 here means that LLU is the only sensible option at this location. I had hoped that the switch from Max to 21CN at this rural exchange would have fixed the issues, but sadly not. So it's back to LLU I go...

My line has always been a bit of an outlier (in a good way): It's dead-on 3km of copper, a fair chunk of which is overhead, but d/s attenuation is only 35 dB. I can get a solid 15 or 16 Mb/s at a 2 dB target.

Throughput on TTR has so far been at sync speed, allowing for overheads, barring the occasional blip. I'm not seeing peak-time slowdowns.Packet loss is minimal. Latency is nominal and stable.

DLM seems to be working intelligently, reducing the d/s target to 3 dB already (starting at 6) and not overdoing it with the interleaving depth/delay/INP. It wasn't phased by an unexpected router reboot yesterday. It's been resyncing every day at 3:30 am.

So far, so good. I'll try to remember to update this once DLM has finished.

Update: Last night was the first night when DLM didn't force a resync, so hopefully that's its job done, after 5 days (I went live on the afternoon of December 3rd).

Stats this morning (down- | up-stream):
SNR: 3.3 | 10.9 dB (so presumably DLM set a 3 dB target)
Atten: 35.0 | 19.7 dB
Sync: 15,200 | 1,019 Kb/s
Depth: 64 | 8
Delay: 8 | 8 ms
INP: 0.5 | 1 symbols
ES rate: 21% (18,000 in last 24 hours) | no u/s errors
SES rate: 0.008% (7 in last 24 hours) | no u/s errors

So a steady ticking up of HEC errors, averaging one every 5 seconds or so. You can't argue DLM is being over-aggressive with the interleaving!

Downstream raw sync is slightly slower than with Plusnet/BTW at the same target margin (but peak-time throughput is much higher).

However, it would be nice to get a bit more upstream. Looks like it's being capped: 1019 or 1020 every resync.

Line remains stable; ES rate now 10% in past 24 hours, with no SESs at all.