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ChrisJenkins
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Is this level of Pre RS errors normal/acceptable?

My 220 MBit service went down this morning and I had to restart my SuperHub. Afterwards I noticed that the Pre-RS error counts were incrementing rapidly. I reset the counters and monitored and in a 20 minute period I saw the following values accumulate:

Pre RS Errors 15756 9119 11494 14132 14585 18244 17304 16899

Post RS Errors are all 0

I am not currently noticing any problems or slowdowns but this level of errors, and the rate of increase, seems abnormal to me.

 

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Dave_cq
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Re: Is this level of Pre RS errors normal/acceptable?

Hi Chris,

That does seem an awful lot for just a 20 minute period, but at least there are no post RS errors so it's not all bad.

Can you post your Upstream and Downstream stats so we can see your power levels please.

 

********* SuperHub 2ac - Asus rt-ac68u Router - Vivid 100Mbps **********

Electron
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Forum Team (Retired) Adam_L
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Re: Is this level of Pre RS errors normal/acceptable?

Hi ChrisJenkins, 

 

Thanks for getting in touch to let us know about your issues with your Pre RS errors, I apologise for any troubles incurred. I will do my best to help get this sorted for you.

I have tested your connection from here and I can see that your Hubs logs show a number of T3 time outs across a few of the upstream channels, I would like to get this investigated further for you by one of our engineers, I will send you a PM (purple envelope at the top) detailing what's required in order to proceed with making the booking.

Please respond to me there and I'll get this sorted for you.

Take care, 

Thanks, 

Adam.


Tech fan? Have you read our Digital life blog yet? Check it out


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Dave_cq
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Re: Is this level of Pre RS errors normal/acceptable?

Hi Chris,

That does seem an awful lot for just a 20 minute period, but at least there are no post RS errors so it's not all bad.

Can you post your Upstream and Downstream stats so we can see your power levels please.

 

********* SuperHub 2ac - Asus rt-ac68u Router - Vivid 100Mbps **********

Electron
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ChrisJenkins
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Re: Is this level of Pre RS errors normal/acceptable?

Here they are:

Screen Shot 2016-11-25 at 08.41.53.pngScreen Shot 2016-11-25 at 08.42.21.png

 

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Dave_cq
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Re: Is this level of Pre RS errors normal/acceptable?

Right, well now that I can see the images there doesn't seem to be anything obviously wrong with the power levels or SNR.  The Upstream power levels are towards the high end but still within the acceptable range of 31 to 51dBmV.

I'm intrigued that you have 4 rather than 2 Upstream channels connected.  Which hub is it?

 

********* SuperHub 2ac - Asus rt-ac68u Router - Vivid 100Mbps **********

Electron
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ChrisJenkins
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Re: Is this level of Pre RS errors normal/acceptable?

I'm on the 220 Mbit service. I believe it is a SuperHub2 (see below):

Screen Shot 2016-11-25 at 11.21.31.png 

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Superuser
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Re: Is this level of Pre RS errors normal/acceptable?

When you think about it, the pre RS errors are not that great. At 200Mbps 240 billion bits would have been received by the hub in 20 mins, so 15,000 errors is a very small percentage.

The DOCSIS specs states that the codeword error should be better than 9 x 10 *-7 which equates to some 216000 errors over 20 mins. As said above, the RS algorithm has corrected these errors so no deterioration of service should be expected as you are experiencing. More on error rates here.

However, the relative high amount of Pre RS errors would suggest that your downstream is not quite as clean as it should be, so it would be worth keeping one eye on it.

On a side note, all SHs should be capable of 4 upstreams as they must support 4 upstream channels to comply with DOCSIS 3 specifications..

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Forum Team (Retired) Adam_L
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Re: Is this level of Pre RS errors normal/acceptable?

Hi ChrisJenkins, 

 

Thanks for getting in touch to let us know about your issues with your Pre RS errors, I apologise for any troubles incurred. I will do my best to help get this sorted for you.

I have tested your connection from here and I can see that your Hubs logs show a number of T3 time outs across a few of the upstream channels, I would like to get this investigated further for you by one of our engineers, I will send you a PM (purple envelope at the top) detailing what's required in order to proceed with making the booking.

Please respond to me there and I'll get this sorted for you.

Take care, 

Thanks, 

Adam.


Tech fan? Have you read our Digital life blog yet? Check it out


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