Max: Upstream rate = 30116 Kbps, Downstream rate = 83260 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 59997 Kbps
I'm not sure how far from the cabinet the hosting site is. SNR down is 8.7db, and SNR up is 12.4db - I understand from the reading that I've done that these SNRs are quite decent, albeit not fantastic, and that I should probably be able to achieve more like the full, max-attainable 30MBPs upstream.
In FTTC, BT always use a target SNRM of 6dB. If you are getting something higher, it is either because
a) you are already sync'ed at the maximum speed for the package, or
b) because DLM has "banded" your connection to sync at a deliberately lower speed, or
c) You synced at 6dB, but there is now less background noise on your line.
Upstream, you are at the maximum speed of 20Mbps. It won't go faster (perhaps you missed something; FTTC maxes out at 20Mbps), so no chance of 25 or 30 there; the extra SNRM there is just additional spare.
Downstream, your actual sync is a few bytes under 60Mbps ... which is such a nice, round number, that it would make me think that banding has occurred. However, I didn't think that 60Mbps was actually one of the banding ranges that BT uses - so I'm a little unsure. You also mention that your line was only activated yesterday - and it would normally take longer for DLM to choose to add banding.
In fact, it would normally take DLM at least a day longer to take any action at all .. and yet DLM has certainly intervened, because we can see settings of INP=5 and delay=10ms. Another anomaly is that these settings are higher than bare minimum (INP=3, delay=8ms) - and it would normally take DLM another day before it turned settings up from the minimum.
DLM's job is to monitor your line for instability - either too high an error rate (using the ES value), or too high a rate of resyncs. DLM is known to be able to take faster action if it thinks your line is very unstable ... so perhaps this is what happened - especially if you think the modem had locked up in some way.
(TL;DR section: Too many errors!)
Right now, you have a low rate of ES's (64 in 3 hours wouldn't worry DLM), but we should expect it to be low now: the intervention aims to swap all errors into being correctable FECs. However, the amount of uncorrectable FECs (RSUnCorr of 645199) seems high relative to the number of corrected FECs (RSCorr of 7799843): Whatever interference you are suffering, it is bad enough to defeat the interleaving+FEC protection too frequently. Likewise the number of CRC's (at 23901) is quite high - and the only good news is that they are concentrated into a very few seconds (hence just 64 Errored Seconds).
For comparison, my old line would not trigger DLM at all. It would see around 600-800 ES's per day, and 6,000-8,000 CRC's per day.
I get the feeling that your line, without DLM intervention, would be suffering from a very high level of errors. And that DLM hasn't yet got a handle on the settings it needs to eradicate them well.
This points you at some actions going forward - with the distinct aim to increase stability of your line.
a) Try not to resync your modem much; you'll likely make things worse in the short term
b) Don't worry about reconnecting the router (or rebooting it); that doesn't cause a resync, and is a better way to reconnect.
c) Keep DslStats going - but pay attention to the graphs showing errors: CRC and FEC errors, and the ES per hour. Look for patterns in the times of high error rates - does it coincide with heating, for example.
Judging by the attenuation figures, I'd say your line is around 350m from the cabinet, assuming the line is of 0.5mm copper. The figures are almost identical to my old line mentioned above.
Author
Topic: Actual sync significantly lower than max attainable (Read 6237 times)