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Author Topic: Upstream Downstream SNR  (Read 1367 times)

Loading

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Upstream Downstream SNR
« on: May 14, 2014, 03:41:10 PM »
When the few tones at the end of the upstream are disabled, the downstream snr is higher, and can sync at a higher speed. With the tones enabled 2016kbps at 4.0db, 2272kbps at 4.0db. This comes from disabling tone 24 to 32. Whilst still having the same 448kbps sync. Why does the upstream connection affect the downstream so much. Some tones gain 3db just by disabling these tones.
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konrado5

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Re: Upstream Downstream SNR
« Reply #1 on: May 14, 2014, 04:38:15 PM »
It is very curious. Could you attach SNR and bit-loading graphs at two different states of affair?

Best regards
konrado5
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Loading

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Re: Upstream Downstream SNR
« Reply #2 on: May 14, 2014, 06:45:25 PM »
As attached the snr is visibly higher and more stable?. Also just noticed the QLN has a odd pattern at the start, not related to the disabling of the tone but weird.
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konrado5

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Re: Upstream Downstream SNR
« Reply #3 on: May 14, 2014, 08:00:46 PM »
Quote from: Loading
s attached the snr is visibly higher and more stable?
I don't see it. Could you attach SNR, bit-loading and Hlog graph from DSLStats?
Quote from: Loading
Also just noticed the QLN has a odd pattern at the start, not related to the disabling of the tone but weird.
Probably DSLAM doesn't send QLN for upstream tones to your router. Upstream QLN can be measured only by CO. Downstream QLN can be measured by CPE. If someone see upstream measurements, it see it because CPE and CO exchange information.

Best regards
konrado5
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