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Signifgicant number of Pre/Post-RS errors on one single channel

fjama13
On our wavelength

I have a Hub 5, and there are many Pre and Post-RS errors on a single downstream channel. I was wondering if anyone could tell me if there is anything in the house that can cause interference on channel 8 (187000000Hz). I have tightened the cable and checked to see if anything would cause the cable to be deformed etc. 

I have had 2 engineer visits, and they blame modem mode, but I do not know how that can cause it. I have packet loss and reduced speeds (around 300Mbps instead of 350-380Mbps). I have provided the router stats below.

31 REPLIES 31

fjama13
On our wavelength

Cable Modem Status

Item

Status

Comments

Acquired Downstream Channel(Hz)

259000000

Locked

Ranged Upstream Channel(Hz)

49600000

Ranged

Provisioning State

Online

Operational

 

Downstream bonded channels

Channel

Frequency (Hz)

Power (dBmV)

SNR (dB)

Modulation

Channel ID

1

259000000

3.5

40

QAM 256

16

2

139000000

7.3

39

QAM 256

1

3

147000000

7.2

40

QAM 256

2

4

155000000

7.1

39

QAM 256

3

5

163000000

6.8

39

QAM 256

4

6

171000000

6.6

40

QAM 256

5

7

179000000

6.6

40

QAM 256

6

8

187000000

6.4

40

QAM 256

7

9

195000000

6.1

40

QAM 256

8

10

203000000

5.7

40

QAM 256

9

11

211000000

5.7

39

QAM 256

10

12

219000000

5.1

40

QAM 256

11

13

227000000

4.9

40

QAM 256

12

14

235000000

4.9

40

QAM 256

13

15

243000000

4.7

40

QAM 256

14

16

251000000

4.2

40

QAM 256

15

17

267000000

3.4

40

QAM 256

17

18

275000000

3.3

40

QAM 256

18

19

283000000

3.7

40

QAM 256

19

20

291000000

4.5

40

QAM 256

20

21

299000000

4.9

40

QAM 256

21

22

307000000

4.9

40

QAM 256

22

23

315000000

4.8

40

QAM 256

23

24

323000000

4.9

40

QAM 256

24

25

331000000

4.8

40

QAM 256

25

26

339000000

5

40

QAM 256

26

27

347000000

5.2

40

QAM 256

27

28

355000000

5.4

40

QAM 256

28

29

363000000

5.2

40

QAM 256

29

30

371000000

5.2

40

QAM 256

30

31

379000000

5.6

40

QAM 256

31

 



fjama13
On our wavelength

Downstream bonded channels

Channel

Locked Status

RxMER (dB)

Pre RS Errors

Post RS Errors

1

Locked

40

0

0

2

Locked

39

4

0

3

Locked

40

2

0

4

Locked

39

1

0

5

Locked

39

4

0

6

Locked

40

4

0

7

Locked

40

2

0

8

Locked

40

631

2841

9

Locked

40

1

0

10

Locked

40

1

0

11

Locked

39

0

0

12

Locked

40

3

0

13

Locked

40

4

0

14

Locked

40

2

0

15

Locked

40

2

0

16

Locked

40

0

0

17

Locked

40

0

0

18

Locked

40

0

0

19

Locked

40

0

0

20

Locked

40

1

0

21

Locked

40

0

0

22

Locked

40

0

0

23

Locked

40

1

0

24

Locked

40

2

0

25

Locked

40

1

0

26

Locked

40

0

0

27

Locked

40

1

0

28

Locked

40

1

0

29

Locked

40

1

0

30

Locked

40

1

0

31

Locked

40

0

0

 

fjama13
On our wavelength

Upstream bonded channels

Channel

Frequency (Hz)

Power (dBmV)

Symbol Rate (ksps)

Modulation

Channel ID

0

49600000

41.8

5120

QAM 64

1

1

43100000

41.3

5120

QAM 64

2

2

36600000

40.8

5120

QAM 64

3

3

30100000

40

5120

QAM 64

4

4

23600000

39.8

5120

QAM 64

5

Upstream bonded channels

Channel

Channel Type

T1 Timeouts

T2 Timeouts

T3 Timeouts

T4 Timeouts

0

ATDMA

0

0

0

0

1

ATDMA

0

0

0

0

2

ATDMA

0

0

0

0

3

ATDMA

0

0

0

0

4

ATDMA

0

0

0

0

 

fjama13
On our wavelength

General Configuration

Network access

Allowed

Maximum Number of CPEs

3

Baseline Privacy

Enabled

DOCSIS Mode

3.1

Config file

DHSUBsgvca69834ncxv9873254k;f

Primary Downstream Service Flow

SFID

5287

Max Traffic Rate

402500089 bps

Max Traffic Burst

42600bytes

Min Traffic Rate

0 bps

SFID

21338

Max Traffic Rate

128000 bps

Max Traffic Burst

4000bytes

Min Traffic Rate

0 bps

Primary Upstream Service Flow

SFID

6721

Max Traffic Rate

38500089 bps

Max Traffic Burst

42600bytes

Min Traffic Rate

0 bps

Max Concatenated Burst

42600bytes

Scheduling Type

Best Effort

SFID

26330

Max Traffic Rate

128000 bps

Max Traffic Burst

4000bytes

Min Traffic Rate

0 bps

Max Concatenated Burst

1522bytes

Scheduling Type

Best Effort

 

fjama13
On our wavelength

Network Log

Time

Priority

Description

04-04-2023 11:40:52

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 11:40:52

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 10:50:26

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 10:50:26

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 10:40:46

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 10:40:46

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 10:40:22

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 10:40:22

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 09:37:28

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 09:37:28

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 09:29:59

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 09:29:59

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 07:59:13

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 07:59:13

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 07:49:06

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 07:49:06

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 04:57:31

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 12 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 04:57:31

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:56:47

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:56:47

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:27:05

notice

CM-STATUS message sent. Event Type Code: 3; Chan ID: N/A; DSID: 830767; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:26:56

warning

Unicast DSID PSN startup error

04-04-2023 03:26:47

notice

US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:26:47

warning

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:26:43

notice

REGISTRATION COMPLETE - Waiting for Operational status

04-04-2023 03:26:37

warning

RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:26:37

warning

RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

04-04-2023 03:26:37

warning

Dynamic Range Window violation

04-04-2023 03:26:37

warning

Dynamic Range Window violation

04-04-2023 03:26:37

warning

Dynamic Range Window violation

04-04-2023 03:26:37

warning

Dynamic Range Window violation

04-04-2023 03:26:37

warning

RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

 

fjama13
On our wavelength

Hi,

Seems to be getting worse, with upstream now being affected. The upstream modulation is now at 16QAM instead of 64QAM. I don't see how modem mode is causing this, as I am now on router mode.

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
04960000041.55120QAM 161
143100000415120QAM 162
23660000040.85120QAM 163
33010000040.55120QAM 164
423600000405120QAM 165

The post RS errors are cable noise issues, quite unrelated to Modem mode it was a foolish description of the problem by the engineer.

Provided the Post RS Errors on DS Channel 8 are not continuing to rise, that could have been a past fault that has since cleared.

If the errors continue to rise, noise in entering the cable, there may be loose connection or a damaged coax cable.

fjama13
On our wavelength

It has increased significantly now can one of the members of the VM forum team book me an appointment with an engineer please?

unisoft
Knows their stuff

@fjama13 wrote:

It has increased significantly now can one of the members of the VM forum team book me an appointment with an engineer please?


If its just one channel that has an issue it won't matter as there are many other bonded channels looking good and there is enough capacity for your speed using those. If there are several channels and the rate keeps going up then that's an issue of noise.