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budgiesmuggler
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Dropping connection

Hi Guys,

I have recently noticed that our normally rock solid virgin fiber connection has started to drop causing frequent need to reboot the router.

We have a relatively straight forward set up at home router > small switch (no loops) > Draytek AP located upstairs, connections are split with the upstairs devices connected to the AP on 2.4 ghz and down stairs on the 5ghz , also have two hard wired PC's that also loose connectivity. even shut down the switch and AP and still have the issue 

Checking the network status the below figures are being returned.. to those in the know do the down and upstream trends appear correct considering the pre and post RS errors? Thanks in advance

Software Version   "V1.01.33"
Hardware Version   3.11
Downstream Channels Lock Status Channel ID Frequency Modulation Rx Power RxMER Pre RS Errors Post RS Errors
Locked13267000000 Hz256 QAM3.2 dBmV 37.9 dB9706987574
Locked11251000000 Hz256 QAM2.5 dBmV 37.1 dB1112300581440829
Locked12259000000 Hz256 QAM2.8 dBmV 37.1 dB848717081108645
Locked14275000000 Hz256 QAM2.8 dBmV 37.6 dB24744516
Locked15283000000 Hz256 QAM1.3 dBmV 36.2 dB621938556
Locked16291000000 Hz256 QAM1.4 dBmV 35.6 dB49245573
Locked17299000000 Hz256 QAM2.0 dBmV 37.1 dB2347499
Locked18307000000 Hz256 QAM2.8 dBmV 37.6 dB1969441

To reset the Pre and Post RS error counts please use the Downstream screen under the router status screen available from the login page.

Upstream Channels Lock Status Channel ID Frequency Modulation Tx Power Mode Channel Bandwidth Symbol Rate
Locked623600000 HzATDMA47.5 dBmV16QAM6400000 Hz5120 Ksym/sec
NotLocked00 Hz 0 dBmV  0 Ksym/sec
NotLocked00 Hz 0 dBmV  0 Ksym/sec
Locked436800000 HzATDMA48.5 dBmV64QAM6400000 Hz5120 Ksym/sec
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Superuser
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Re: Dropping connection

The stats look fine.

However, you have a lot of RS errors on two of your downstream channels which are a concern. The SNR could be fluctuating on these channels and is worth investigating by VM. It would be worth clearing the RS counters to see if they rise rapidly, this will discount any historical errors.

How is the  speed on a device connected directly to the hub by ethernet cable performing.?

A VM Forum team member should hopefully pick up yhe thread within a week and can take a closer look at your connection, or you can phone in for a quicker response.

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budgiesmuggler
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Message 3 of 6
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Re: Dropping connection

Hi Griffin,

 

Thanks for taking the time to look and advise .. much appreciated.

As advised i have reset the counters and see what this turns up.

Hard wired devices directly on the router perform in much the same way the connection runs at a decent speed up until the the connection appears to drop (ran multiple pings from a hardwired pc and a wirless and the pings drop out at the same time) 

Resetting the counters the PRE RS starts to increment isnt this indicitive that error packets are being sent to the router from external and then being corrected?

Kind regards

 

Rick 

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budgiesmuggler
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Re: Dropping connection

Looks like something is up as the Post RS Errors on the down stream are incrementing 

 

Downstream   DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8

Frequency (Hz)267000000275000000283000000291000000299000000307000000315000000323000000
Lock Status(QAM Lock/FEC Sync/MPEG Lock)LockedLockedLockedLockedLockedLockedLockedLocked
Channel ID1314151617181920
Modulation256QAM256QAM256QAM256QAM256QAM256QAM256QAM256QAM
Symbol Rate (Msym/sec)6.9520006.9520006.9520006.9520006.9520006.9520006.9520006.952000
Interleave DepthI=12
J=17
I=12
J=17
I=12
J=17
I=12
J=17
I=12
J=17
I=12
J=17
I=12
J=17
I=12
J=17
Power Level (dBmV)2.982.621.131.392.212.992.973.66
RxMER (dB)35.9734.9333.7234.4836.6137.3637.0936.17
Pre RS Errors2879241666898738942384215317671003
Post RS Errors29945159263238171644
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Superuser
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Re: Dropping connection

Yes you are correct, the Pre RS errors are corrupted packets that are hitting the router. The Reed Solomon algorythm then tried to repair the corrupted packets, if the packet cannot be repaired a Post RS error is thrown and the packet is retransmitted.

Yes, there is something afoot as you say. the RS errors are increasing on a few channels and the SNR is dropping as well and are marginal to say the least.

This would be indicative of noise on the circuit which VM will need to investigate.

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Forum Team
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Re: Dropping connection

Hi budgiesmuggler,

I've taken a thorough look at your connection and there has been noise on the upstream segment though, for the past week, there appears to be only one incident, on the 20th.

If the disconnections are still evident I should like to arrange for an engineer appointment to check things over. After which, if no resolution is forthcoming, we can investigate further. Please post an update and I'll be in touch to make arrangements for an appointment if needed.

 


Jen
Forum Team



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