Cable Forum - View Single Post - 50M Packet loss, very slow speeds and pain

Sephiroth · 24-12-2012, 21:28

I can see what's wrong. The 2nd downstream channel has poor SNR (not out of theoretical range for 256QAM but at 120 meg it's poor). This means that your SH cant properly assemble packets if the interleaved data it receives is corrupted (post-RS errors).

You can check this for yourself in modem mode (I think that's your mode). You log into the admin page of the SH. You invoke a new browser tab and put this into the URL line:

http://192.168.100.1/advanced_list.asp

You will see the full advanced manu. Get to the stats and you'll see the Pre-RS and Post-RS errors. I bet that DS channel 2 looks tasty.

The T3 errors occur if the modem can't properly read the keep-alives and so can't respond; the T4 event occurs when this happens on 16 consecutive retries and so reboots.

If a single channel is misbehaving then it's either the SH (unlikely) or something in the optical node which a visiting engineer can't fix. A reboot (or better still leaving the SH off overnight) might give you different downstream channels and that could cure the condition.

Hope that helps.

24-12-2012, 21:28	#7
Sephiroth Wisdom & truth Join Date: Jul 2009 Location: RG41 Services: RG41: 1Gig VOLT Rutland: Gigaclear 400/400 Posts: 12,504	Re: Packet loss, very slow speeds and pain I can see what's wrong. The 2nd downstream channel has poor SNR (not out of theoretical range for 256QAM but at 120 meg it's poor). This means that your SH cant properly assemble packets if the interleaved data it receives is corrupted (post-RS errors). You can check this for yourself in modem mode (I think that's your mode). You log into the admin page of the SH. You invoke a new browser tab and put this into the URL line: http://192.168.100.1/advanced_list.asp You will see the full advanced manu. Get to the stats and you'll see the Pre-RS and Post-RS errors. I bet that DS channel 2 looks tasty. The T3 errors occur if the modem can't properly read the keep-alives and so can't respond; the T4 event occurs when this happens on 16 consecutive retries and so reboots. If a single channel is misbehaving then it's either the SH (unlikely) or something in the optical node which a visiting engineer can't fix. A reboot (or better still leaving the SH off overnight) might give you different downstream channels and that could cure the condition. Hope that helps. __________________ *Seph.* My advice is at your risk.