Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: youngsyp on March 07, 2020, 07:23:58 AM
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Hi,
I've noticed that in most of the posts I read on here, with stats included, the attainable rates are typically what the line is capable of, in the perfect conditions. That's not the case with what I have reported. For example, currently the attainable rate on the line is circa 56.7Mb/s down, actual 56.1Mb/s down. However, it regularly syncs at above that, sometimes way above that. It's hit 74Mb/s once for example but circa 60Mb/s in about typical with a 6dB SNRM target.
So I guess my question is, why am I seeing a transient attainable rate when what I see for others are the actual rate their line is capable of?
Paul
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the attainable rates are typically what the line is capable of, in the perfect conditions.
I think you have misunderstood what the attainable rate represents. It is not what the line would be capable of in perfect conditions. It is an estimate of what the line is capable of in the current conditions.
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Don't forget that the max attainable rate is also often over inflated if the line has error protection and interleaving applied.
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To summarise, if your sync is higher than your attainable then that merely means your current line condition is worse than it was during your last sync, but its still stable enough to continue to function.
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Thanks for the responses, all very helpful.
I'm still trying to get my head round a few things, that I'm unsure of. Like for instance, after all my recent issues, I think they've finally fixed the underlying problem and the line has been up and stable for more than 7 days. However, with ES errors at less than 50 a day on each stream, DLM hasn't lowered target SNRM from 6dB as it had done before any of the issues. Can DLM get 'stuck'? Or could the line be capped? Or am I just being impatient?
Paul
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It was mentioned during the 3dB rollout that DLM takes a lines history in to account.
If the line had a DLM reset after the issues then it shouldn't be a problem.
If there was no DLM reset it could delay or prevent a losing of the target SNRM.
The system isn't designed to lower the SNRM for all users, only this lines deemed stable enough.
50 ES per day with G.INP isn't a very low figure imo.
It isn't excessive either, but by no means very low.
A cap on the sync for a few days can help "nudge" the DLM
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Thanks John.
I should point out that on my line, G.INP is only enabled on the downstream but, I get your point about quantity of ES errors.
What would you suggest as a % cap, to "entice" DLM? Or even an absolute number, given that my sync is 56.515 Mb/s down and 12.706 Mb/s up?
Incidentally, I've also reverted back to a VMG8924, from a Netgear D7000v1, just to see if it would make a difference. Downstream sync is essentially the same but, the D7000 seems to provide a greater upstream sync by around 1Mb/s. I guess that could just be within the normal variance level though. The D7000 also reduced my minimum latency, back to AA, by around 1ms from circa 8ms to 7ms. Something I didn't expect.
Paul