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parkorr
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Superhub 3 upstream modulation issue

This relates to this previous post, but for some reason I cannot reply to it.

https://community.virginmedia.com/t5/QuickStart-set-up-and/Superhub-3-upstream-modulation-issue/m-p/...

 

A Virgin engineer visited today and corrected the upstream and downstream levels.  The 24 downstream channels are now around +5 to +6 dBmV, and the 4 upstream are between 41 and 44 dBmV.  However, he was unable to fix the issue I was originally highlighting, which is that one upstream channel has dropped to 16 qam from 64 qam, resulting in reduced upstream throughput speed.  Despite levels being high for some time, everything was fine until a couple of months ago, when I noticed that intermittently this one channel was changing to 16 qam.  Since then, it has become more frequent, and for the last few weeks has been continuous.  Upstream speed on a LAN connected pc has dropped from around 36Mbps to something like 17 to 22Mbps.  The engineer told me he is seeing errors on the network at the cabinet so suspects a card in the cabinet, or something else within the local Virgin network, is suspect.  How do I progress this to seek a resolution?

 

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

12580033243.5512016 qam12
23940010242512064 qam9
34620000041.8512064 qam8
43260025842.8512064 qam10



Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1ATDMA0010
2ATDMA0000
3ATDMA0000
4ATDMA0000
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gitty
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Re: Superhub 3 upstream modulation issue

It's true that 16-QAM has lower throughput than 64-QAM, but that is probably not the issue. The issue could be packet loss due to noise, which a lower modulation is a sign of.
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parkorr
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Re: Superhub 3 upstream modulation issue

Yes, now that you say that, I think the engineer did use the word "noise" when he mentioned about the errors at the cabinet.  Since this a problem that didn't used to be there, and is getting worse, how do I progress this with Virgin for it to be fixed?

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jbrennand
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Re: Superhub 3 upstream modulation issue

Post up the data from the Downstream channel pages and the Network logs, as well.

Also, in the meantime... if you haven’t already, set up a free and secure “Broadband Quality Monitor” to continually monitor the state of your connection and record any true network dropouts , latency issues, packet drops, etc - it will thus allow you to differentiate between those and simple wifi dropouts. It does it 24/7/365 and it keeps a visual record of any/all of your network disconnections, useful data to have to match to the Network logs (in your Hub settings) and also in discussions with VM - note it will take a few hours to start seeing a sensible picture - post up the “link” to the “share live graph” (as per instructions on the TB website) when you have the first 24h period.

https://www.thinkbroadband.com/broadband/monitoring/quality

--------------------
John
--------------------

I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
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parkorr
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Re: Superhub 3 upstream modulation issue

Downstream bonded channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1203000000633256 qam9
22110000005.833256 qam10
32190000005.934256 qam11
4227000000634256 qam12
52350000006.135256 qam13
6243000000635256 qam14
7251000000635256 qam15
82590000005.535256 qam16
92670000005.434256 qam17
10275000000534256 qam18
112830000005.434256 qam19
122910000005.635256 qam20
13299000000634256 qam21
143070000005.935256 qam22
153150000005.835256 qam23
163230000005.534256 qam24
173310000005.535256 qam25
183710000005.335256 qam26
193790000005.135256 qam27
203870000004.935256 qam28
213950000004.935256 qam29
22403000000535256 qam30
23411000000535256 qam31
244190000005.136256 qam32



Downstream bonded channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1Locked34.328839850
2Locked34.421203790
3Locked3511115530
4Locked354790130
5Locked35.52571150
6Locked35.52405550
7Locked35.52631610
8Locked35.73208250
9Locked355500440
10Locked34.97251760
11Locked355544340
12Locked35.73695470
13Locked35.54015570
14Locked35.54354030
15Locked354975810
16Locked355503450
17Locked35.53715590
18Locked36.3331950
19Locked36.3266640
20Locked36.3337730
21Locked36.3369090
22Locked36.3307890
23Locked36.6193980
24Locked36.6129870
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parkorr
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Re: Superhub 3 upstream modulation issue

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

12579996243.5512016 qam12
23940008842512064 qam9
34620008341.8512064 qam8
43260000042.8512032 qam10



Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1ATDMA0040
2ATDMA0000
3ATDMA0000
4ATDMA0000
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parkorr
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Re: Superhub 3 upstream modulation issue

Network Log

Time Priority Description

30/12/2020 12:18:47criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:39:56noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:37:1Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:37:1criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:37:1Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:35:31Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:35:26criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:35:25Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:35:25criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:20:45noticeLAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:17:17criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:15:25criticalReceived Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:13:9Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:13:4criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:13:4Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:13:3criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 11:08:34criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 10:59:47criticalReceived Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 10:57:27Warning!Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
30/12/2020 10:57:23criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
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parkorr
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Re: Superhub 3 upstream modulation issue

I did have a Broadband Quality Monitor set up, but it has been disabled and not running.  However, here is a snapshot from 18/11/20 when the upstream modulation issue was intermittent and short lived.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/e33674c8c64d73a471af29d0168a337b99...

Here is a link to the live graph which is now enabled.  Now, even a short time after re-enabling the monitor, packet loss can be seen.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/ac5978c6fa53b1d4a665b69bb82b1aff8f...

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