Broadband Related > FTTC and FTTP Issues

Line Stats

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j0hn:

--- Quote ---I've not looked at that... What's the best way of determining that from DSLstats?
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Look at the CRC and LEFTERS graphs at the exact times the SNRM dropped. If you save snapshots you can look back at the CRC graph but LEFTERS doesn't save.


--- Quote ---There were two drops early evening. One was at around 17:40, and the other at 18:50. I was was watching for a resync at around 18:55/19:00 based on the 1st drop, but it didn't happen. However, just after 20:00 it did resync, which was approx 70mins after the 18:50 drop.
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It's not a coincidence that there's 70 mins between the 2 drops either. WTF could it be?

JamesK:

--- Quote from: j0hn on September 20, 2018, 02:15:57 PM ---It's not a coincidence that there's 70 mins between the 2 drops either. WTF could it be?

--- End quote ---
As the retrain reason is 1, my assumption is that it's DLM initiated. I was also assuming that DLM could also set the SNRM profile, thus causing the SNRM dB down to be at 6ish dB upon resync. But as I've proven if I manually restart the modem, it syncs at 3dB.

I also thought DLM only took action several hours later, or during the next day. That's always been my previous experience when on the ECI cabinet. I've never seen it act so quickly, especially when sync on the line was never lost.

Am I correct in thinking if there was an event so bad that sync was lost entirely, the retrain reason would be zero? But it seems a stretch to think 70 mins after an SNRM dip, there would be another worse event which would cause sync to be lost entirely, and be ongoing during the modem retrain.

JamesK:
Had another drop in SNRM this evening at 19:00...


--- Quote from: j0hn on September 20, 2018, 01:16:24 PM ---Do you get a burst of ES or LEFTERS during the brief SNRM crash

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The answer to this is yes... see attached SNRM, CRC & LEFTRS graphs...

It remains to be seen as the SNRM is still 6dB whether I get a DLM initiated resync - my guess at this point is that it won't.

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