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Greenpalmer
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Very poor SnR and lots of Post RS Errors

Yesterday morning something happened and I have lots of critical errors on the network log and since then the SnR has been very low and I have lots of Post RS errors.The network log and downstream data are as follows:

Network Log

Time

Priority

Description

2018-09-24 09:12:37.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:50.00

Warning!

RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:50.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:50.00

Warning!

RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:51.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:51.00

Warning!

RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:52.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:12:58.00

Warning!

Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:16:51.00

critical

Received 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;

2018-09-24 09:18:20.00

Warning!

Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:18:20.00

Warning!

MDD message timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:18:34.00

critical

No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:19:01.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:19:05.00

Warning!

Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:19:16.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:22:15.00

Warning!

RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:22:16.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:22:16.00

Warning!

RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:22:16.00

critical

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

2018-09-24 09:22:20.00

Warning!

Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

 

Downstream bonded channels

Channel

Locked Status

RxMER (dB)

Pre RS Errors

Post RS Errors

1

Locked

36.3

43

8040

2

Locked

36.6

213

6034

3

Locked

37.3

62

6633

4

Locked

37.6

32

6707

5

Locked

36.6

46

8433

6

Locked

36.6

35

7494

7

Locked

36.3

33

7874

8

Locked

36.3

26

7811

9

Locked

36.6

28

10239

10

Locked

36.6

31

8115

11

Locked

36.6

26

7572

12

Locked

36.3

38

7922

13

Locked

34.3

7241

7139

14

Locked

35.5

401

7135

15

Locked

36.3

41

7129

16

Locked

36.3

30

2313

17

Locked

36.6

31

2377

18

Locked

36.3

81

3079

19

Locked

36.3

63

3220

20

Locked

36.3

55

2982

21

Locked

36.3

55

3266

22

Locked

35.7

95

2261

23

Locked

35.7

142

2628

24

Locked

35.7

136

2768

 

Any ideas what the problem is and (more importantly) what the solution is?

 

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jb66
Alessandro Volta
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Message 2 of 15
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Re: Very poor SnR and lots of Post RS Errors

What fault are you experiencing?

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Greenpalmer
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Message 3 of 15
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Re: Very poor SnR and lots of Post RS Errors

Well that is a very reasonable question and in fact everything seems to be functioning reasonably normally.

I have made the post because I do keep an eye on the router logs and statuses and I have never seen anything like this before and am concerned that something has gone wrong.

 

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jb66
Alessandro Volta
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Message 4 of 15
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Re: Very poor SnR and lots of Post RS Errors

The reason I asked as your SNR is the above minimum 34db If only just

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Greenpalmer
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Message 5 of 15
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Re: Very poor SnR and lots of Post RS Errors

My concern is that my SNR has suddenly dropped substantially and I am suddenly getting lots of post RS errors which I haven't been getting before.

Something has happened to my connection and it definitely isn't good.

 

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Very Insightful Person
Very Insightful Person
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Message 6 of 15
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Re: Very poor SnR and lots of Post RS Errors

You missed posting the column with the downstream power levels as well. (SNR is only half of the information)  As well as the upstream power levels.

Is the post RS count rising over time or is it static?

Tim

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Greenpalmer
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Re: Very poor SnR and lots of Post RS Errors

Here's the power levels:

Downstream bonded channels

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

1299000000036256 qam21
23230000000.737256 qam24
33150000000.737256 qam23
43070000000.936256 qam22
5291000000-136256 qam20
6283000000-0.736256 qam19
7275000000-0.236256 qam18
8267000000036256 qam17
92590000000.236256 qam16
102510000000.236256 qam15
112430000000.236256 qam14
122350000000.236256 qam13
132270000000.235256 qam12
142190000000.535256 qam11
152110000000.536256 qam10
162030000000.736256 qam9
171950000000.936256 qam8
181870000000.936256 qam7
19179000000136256 qam6
201710000001.436256 qam5
211630000001.536256 qam4
221550000001.535256 qam3
231470000001.735256 qam2
241390000002.235256 qam1

 

The post RS errors don't seem to be increasing very much at the moment although I will keep an eye on them.

Also I only have two upstream channels at 16qam wheras other people seem to have four upstream channels at 64qam:

Upstream bonded channels

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

15370000048512016 qam65
23260000046.5512016 qam63



Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1ATDMA0000
2ATDMA0000

 

Is there something wrong here as well?

 

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Very Insightful Person
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Message 8 of 15
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Re: Very poor SnR and lots of Post RS Errors

The power levels themselves look sweet although some of the SNR's aren't great, they're still within acceptable limits.

The @ForumTeam will take a look at this but it can take them a few days to do so.

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Greenpalmer
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Message 9 of 15
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Re: Very poor SnR and lots of Post RS Errors

OK ravenstar68, thanks very much

 

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Greenpalmer
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Message 10 of 15
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Re: Very poor SnR and lots of Post RS Errors

This is now getting worse - the SNR has dropped below 34 on channels 13 and 14 and the family say that Netflix has stopped working and just constantly buffers.

Downstream bonded channels

Channel

Frequency (Hz)

Power (dBmV)

SNR (dB)

Modulation

Channel ID

1

299000000

-0.7

36

256 qam

21

2

323000000

-0.2

36

256 qam

24

3

315000000

-0.2

36

256 qam

23

4

307000000

-0.2

36

256 qam

22

5

291000000

-2

36

256 qam

20

6

283000000

-1.7

36

256 qam

19

7

275000000

-1.2

36

256 qam

18

8

267000000

-0.9

36

256 qam

17

9

259000000

-0.7

36

256 qam

16

10

251000000

-0.7

36

256 qam

15

11

243000000

-0.7

36

256 qam

14

12

235000000

-0.7

36

256 qam

13

13

227000000

-0.7

33

256 qam

12

14

219000000

-0.5

33

256 qam

11

15

211000000

-0.4

35

256 qam

10

16

203000000

-0.4

35

256 qam

9

17

195000000

0

36

256 qam

8

18

187000000

0

35

256 qam

7

19

179000000

0

35

256 qam

6

20

171000000

0.4

35

256 qam

5

21

163000000

0.5

35

256 qam

4

22

155000000

0.5

35

256 qam

3

23

147000000

0.7

35

256 qam

2

24

139000000

1.2

35

256 qam

1

 

Downstream bonded channels

Channel

Locked Status

RxMER (dB)

Pre RS Errors

Post RS Errors

1

Locked

36.6

43

0

2

Locked

36.3

83

0

3

Locked

36.6

54

0

4

Locked

36.6

33

0

5

Locked

36.6

62

0

6

Locked

36.3

50

0

7

Locked

36.3

42

0

8

Locked

36.3

64

0

9

Locked

36.6

81

0

10

Locked

36.6

34

0

11

Locked

36.3

39

0

12

Locked

36.3

66

0

13

Locked

33.8

46956

0

14

Locked

33.8

104449

0

15

Locked

35.7

110

0

16

Locked

35.7

91

1

17

Locked

36.3

148

7

18

Locked

35.7

153

65

19

Locked

35.5

143

52

20

Locked

35.5

147

27

21

Locked

35.7

180

2

22

Locked

35.5

212

53

23

Locked

35.7

358

60

24

Locked

35.5

921

17

 

 

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