Start a New Discussion

Start a New Discussion

Orbi WiFi 7 RBE973
Reply

Re: CM1000 intermittent connection loss on XFinity cable

G0atHax0r
Aspirant
Aspirant
‎2020-05-14 11:13 AM
‎2020-05-14 11:13 AM

CM1000 intermittent connection loss on XFinity cable

Hi All,

 

I'm troubleshooting what seems to be intermittent drops throughout the day on XFinity cable... and the culprit is either the CM1000 going bad, or some kind of line quality/hardware issues on the XFinity side.  Before you ask, no there aren't any splitters between the modem and the XFinity cable box.  I have worked with XFinity support, who is reporting that all is fine on their end, and is pointing the finger at the modem.  They ran line quality tests, and I'm getting excellent speedtests when things are working.  Here's the order of events when I catch it happening:

 

1.) Internet service is lost

2.) The green "internet" icon light on the CM1000 starts flashing, and will eventually reconnect and go solid. (2nd light from the bottom, above the network icon)

3.) Internet service returns

4.) Total time occurred during outage is usually a minute or 2, while minimal, is disruptive enough to anger those in the household as it interrupts streaming, browsing, you name it.

 

I have pulled some logs from the CM1000 to get some feedback on what these might indicate?  Is it truly an XFinity issue, or is this just normal with the modem going bad?

 

Here are some events from 5/11:

2020-05-11, 12:01:46	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 12:00:51	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 12:00:30	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 12:00:16	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:54:16	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:43:53	Critical (3)	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:43:50	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:43:38	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:43:36	Critical (3)	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:43:34	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:43:07	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:42:50	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-11, 11:42:49	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;

Here are some events from 5/14:

2020-05-14, 10:42:54	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:42:46	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
2020-05-14, 10:41:35	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:41:29	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:41:28	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:41:12	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:41:11	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:47	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:47	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:35	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:34	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:22	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:22	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:11	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:40:10	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:39:52	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:39:51	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:39:03	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:39:02	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:38	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:32	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:32	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:30	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:25	Notice (6)	CM-STATUS message sent. Event Type Code: 21; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:24	Notice (6)	CM-STATUS message sent. Event Type Code: 20; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:38:24	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:37:05	Notice (6)	CM-STATUS message sent. Event Type Code: 4; Chan ID: 5 11 12 13 14 15 16 17 18 19 20 21 22 23 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:37:05	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:37:04	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:37:02	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:37:01	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:37:01	Notice (6)	CM-STATUS message sent. Event Type Code: 22; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:58	Warning (5)	MDD message timeout;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:57	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:45	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:35	Notice (6)	CM-STATUS message sent. Event Type Code: 4; Chan ID: 5 11 12 13 14 15 16 17 18 19 20 21 22 23 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:20	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:20	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:36:15	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;

 

Thank you very much for your support, ideas and feedback!

 

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 1 of 12
0 Kudos
Reply

Accepted Solutions
G0atHax0r
Aspirant
Aspirant
‎2020-05-29 11:55 AM
‎2020-05-29 11:55 AM

Re: CM1000 intermittent connection loss on XFinity cable

So here's an update to my situation... it seems that @Googalabosh was experiencing similar issues, so I'll write down my findings/experience here...

 

1.) XFinity tech came out and ran tests from the entry point to my CM1000 cable modem - no problems (and no, there are no splitters... it's a straigh run)

2.) XFinity tech ran a test from the entry point to the junction box at the street - no problem.

3.) XFinity tech ran a test from the junction box at the street, to the nearest node - again, no problems... 

 

He said everything according to his readings were within parameters and nothing looked abnormal.  This was frustrating both to me and him, since we couldn't pinpoint anything weird.  I asked him if he could put a network monitor on our account, which he was happy to do -- and I would *recommend* you asking for this same thing.  This will give them detailed reports of when things misbehave, which is what I suspect happened in my case.

 

After the tech left, my device continued to drop for the next few days off and on throughout the day... then, things stabilized.  My connection has not dropped for almost 4 days straight now., which is unheard of.  🙂  The tech said he or someone else would call back and give an update, but I have not heard anything yet.  I will definitely find out what the problem was, but I suspect it had to do with some changes at the upstream node.

 

I started keeping careful track of what my modem stats were looking like throughout the day, and found that if the downstream channels power dropped below -4.5 or -5 dBmV, which also seems to drop the SNR/MER to below 36dB, then I would start accumulating more and more uncorrectable codewords, including drops.  Since they did something on their end, my power has remained around -2 or -3dBmV and the SNR/MER remains at 40dB on average... 

 

I would focus on ensuring that these values are in the middle of the range (Power should ideally be at 0dBmV and SNR/MER should ideally be at 40dB), but it fluctuates up or down... which typically is still OK, but I guess certain modems/connections are more finicky than others.  Hope this helps!

View solution in original post

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 11 of 12
0 Kudos
Reply

All Replies
plemans
Guru Guru
Guru
‎2020-05-17 11:47 AM
‎2020-05-17 11:47 AM

Re: CM1000 intermittent connection loss on XFinity cable

do you also have the Cable connection page to go with the logs?
Message 2 of 12
0 Kudos
Reply
G0atHax0r
Aspirant
Aspirant
‎2020-05-17 05:57 PM
‎2020-05-17 05:57 PM

Re: CM1000 intermittent connection loss on XFinity cable

@plemans wrote:
do you also have the Cable connection page to go with the logs?

Unfortunately I don't have a snapshot of these connection logs when the issue is occurring, but I'll try for next time.  Here's what they look like when things are working:

 

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure</tabindex=-1>

ProcedureStatusComment
Acquire Downstream Channel579000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnableBPI+
IP Provisioning ModeHonor MDDIPv6 only

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>

ChannelLock StatusModulationChannel IDFrequencyPowerSNR / MERUnerrored CodewordsCorrectable CodewordsUncorrectable Codewords
1LockedQAM25617579000000 Hz-2.7 dBmV39.6 dB462097131477914713
2LockedQAM2561483000000 Hz-3.1 dBmV39.1 dB4523343137070
3LockedQAM2562489000000 Hz-2.9 dBmV39.2 dB64685880590328809
4LockedQAM2563495000000 Hz-2.8 dBmV39.6 dB64692870565227540
5LockedQAM2564501000000 Hz-3.0 dBmV39.3 dB64697151553126572
6LockedQAM2565507000000 Hz-2.8 dBmV39.4 dB64700840312014280
7LockedQAM2566513000000 Hz-2.6 dBmV39.6 dB64706758517324780
8LockedQAM2567519000000 Hz-2.9 dBmV39.3 dB6471109319307965
9LockedQAM2568525000000 Hz-3.3 dBmV39.1 dB6472023113254830
10LockedQAM2569531000000 Hz-3.1 dBmV39.3 dB64724479548026491
11LockedQAM25610537000000 Hz-3.0 dBmV39.4 dB64723792583627966
12LockedQAM25611543000000 Hz-3.1 dBmV39.3 dB64729815517024677
13LockedQAM25612549000000 Hz-2.9 dBmV39.4 dB647357037821044
14LockedQAM25613555000000 Hz-2.6 dBmV39.6 dB64739574560827443
15LockedQAM25614561000000 Hz-2.7 dBmV39.3 dB64742700593028637
16LockedQAM25615567000000 Hz-2.9 dBmV39.4 dB64745371566127281
17LockedQAM25616573000000 Hz-2.7 dBmV39.5 dB64769644941825081
18LockedQAM25618585000000 Hz-2.8 dBmV39.5 dB647741721717815246
19LockedQAM25619591000000 Hz-2.7 dBmV39.5 dB64783828220255417
20LockedQAM25620597000000 Hz-2.3 dBmV39.6 dB64794547187602065
21LockedQAM25621603000000 Hz-2.4 dBmV39.5 dB64793880215154126
22LockedQAM25622609000000 Hz-2.3 dBmV39.5 dB64798198218913794
23LockedQAM25623615000000 Hz-1.8 dBmV39.8 dB64808961152051087
24LockedQAM25629459000000 Hz-2.8 dBmV39.4 dB64797187556427605
25LockedQAM25634465000000 Hz-2.8 dBmV39.3 dB64798205591528846
26LockedQAM25635471000000 Hz-2.7 dBmV39.4 dB64792486579027849
27LockedQAM25636477000000 Hz-3.0 dBmV39.1 dB64794992587128804
28LockedQAM25638429000000 Hz-2.3 dBmV39.4 dB64767490524625934
29LockedQAM25639435000000 Hz-2.8 dBmV39.1 dB64779295423514
30LockedQAM25640441000000 Hz-3.1 dBmV39.1 dB647749979202066
31LockedQAM25641453000000 Hz-2.6 dBmV39.5 dB64777052585228958
32Not LockedUnknown00 Hz0.0 dBmV0.0 dB000

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>

ChannelLock StatusModulationChannel IDFrequencyPower
1LockedATDMA135800000 Hz47.0 dBmV
2LockedATDMA229400000 Hz46.8 dBmV
3LockedATDMA323000000 Hz46.5 dBmV
4Not LockedUnknown00 Hz0.0 dBmV
5Not LockedUnknown00 Hz0.0 dBmV
6Not LockedUnknown00 Hz0.0 dBmV
7Not LockedUnknown00 Hz0.0 dBmV
8Not LockedUnknown00 Hz0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>

ChannelLock StatusModulation / Profile IDChannel IDFrequencyPowerSNR / MERActive Subcarrier Number RangeUnerrored CodewordsCorrectable CodewordsUncorrectable Codewords
1Locked0, 1, 2, 337690000000 Hz0.4 dBmV32.0 dB1228 ~ 286729898655023676996617558813
2Not Locked000 Hz0.0 dBmV0.0 dB0 ~ 4095000

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>

ChannelLock StatusModulation / Profile IDChannel IDFrequencyPower
1Not LockedUnknown00 Hz0 dBmV
2Not LockedUnknown00 Hz0 dBmV

Current System Time: Sun May 17 19:54:51 2020System Up Time: 26:39:57

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 3 of 12
0 Kudos
Reply
plemans
Guru Guru
Guru
‎2020-05-18 05:46 AM
‎2020-05-18 05:46 AM

Re: CM1000 intermittent connection loss on XFinity cable

You have a bunch of errors in your line. Not a few, a bunch. 

If you don't have any splitters, attenuators, amplifiers, or extended runs, then your isp needs to check the line. 

goal is to connect right where the coax enters the home to prevent the isp from saying the issues is the wiring within the home. 

Message 4 of 12
0 Kudos
Reply
G0atHax0r
Aspirant
Aspirant
‎2020-05-18 06:33 AM
‎2020-05-18 06:33 AM

Re: CM1000 intermittent connection loss on XFinity cable

@plemans wrote:

You have a bunch of errors in your line. Not a few, a bunch. 

If you don't have any splitters, attenuators, amplifiers, or extended runs, then your isp needs to check the line. 

goal is to connect right where the coax enters the home to prevent the isp from saying the issues is the wiring within the home. 

I appreciate your feedback, @plemans!  Could you please share some more specific information?  I'm assuming you're talking about these sample errors that keep repeating below, right?  I'm pretty decent at deciphering windows server errors and whatnot, but cable modem/communication-specific errors are not my expertise.  What typically are the cause for these kinds of errors, and what should I be looking out for?  For instance, could this be an physical cable problem?  If so, why would it only happen intermittently?  Could it be the CM1000 flaking out?  Why or why not?  Would I see different errors?  Is it an upstream hardware issue not producing enough voltage, or not supplying what's necessary to maintain a sync connection, or timing hardware failures?

 

2020-05-14, 10:41:35	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:41:29	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;
2020-05-14, 10:41:28	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=a0:04:60:fc:37:50;CMTS-MAC=00:01:5c:a2:6a:51;CM-QOS=1.1;CM-VER=3.1;

 

I don't have any splitters, attenuators, amplifiers or extended runs.  I appreciate your help! 🙂

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 5 of 12
0 Kudos
Reply
plemans
Guru Guru
Guru
‎2020-05-18 07:01 AM
‎2020-05-18 07:01 AM

Re: CM1000 intermittent connection loss on XFinity cable

I'm talking your codewords. Some are correctable and some aren't. Tie those in together with your logs and there's usually line issues causing it. 

It could be damage to a coax line, bends, wear, or even moisture in the line. It could be corrosion to a connector. it could be a poorly installed connector. it could be an issues at the box. Its tough to say exactly. 

but if you have the modem directly connected to where the coax is entering the home and you're still getting those, your isp needs to check the line. 

 

It always potentially can be a modem. connectors/hardware does go bad sometimes.

 

And sometimes the isp will say "our lines fine, its your 3rd party modem". I've had to rent an ISP modem for a month to prove it wasn't the modem so they'd fix a line before. Problem with that is that some isp's are locking down their modem page so the home user can't even check anymore. 

Message 6 of 12
0 Kudos
Reply
G0atHax0r
Aspirant
Aspirant
‎2020-05-18 07:27 AM
‎2020-05-18 07:27 AM

Re: CM1000 intermittent connection loss on XFinity cable

Ahhh!  Understood.  So the codewords are some type of CRC.  What do these correctable/uncorrectable codeword values normally look like?  Just extremely low numbers right that indicate no noise on the line, right?  Seeing that there's a similar range of errors like this across most of the channels, then I guess that could be indicative of a line/connector problem.

 

Lol... that's exactly what the isp said... they don't see any problems with the line when they run their tests, but after sharing some of these SYNC/No ranging response errors from the logs, they seemed a little more willing to admit to it possibly being a cable or upstream equipment issue.  If it was the latter, you'd think more neighbors would be complaining though.  So it must be a cable/connector.  I believe the next step is begging them to come out and do a hands-on test.  Thanks again for your help @plemans!

 

@plemans wrote:

I'm talking your codewords. Some are correctable and some aren't. Tie those in together with your logs and there's usually line issues causing it. 

It could be damage to a coax line, bends, wear, or even moisture in the line. It could be corrosion to a connector. it could be a poorly installed connector. it could be an issues at the box. Its tough to say exactly. 

but if you have the modem directly connected to where the coax is entering the home and you're still getting those, your isp needs to check the line. 

 

It always potentially can be a modem. connectors/hardware does go bad sometimes.

 

And sometimes the isp will say "our lines fine, its your 3rd party modem". I've had to rent an ISP modem for a month to prove it wasn't the modem so they'd fix a line before. Problem with that is that some isp's are locking down their modem page so the home user can't even check anymore. 

 

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 7 of 12
0 Kudos
Reply
FURRYe38
Guru Guru
Guru
‎2020-05-18 11:00 AM
‎2020-05-18 11:00 AM

Re: CM1000 intermittent connection loss on XFinity cable

Have you factory reset the modem? 

Be sure your using good quality RG6 coax cable up to the modem. 

 

I would contact NG support and ask for additional help and information. Ask about a RMA if thats an option.

https://www.netgear.com/support/#

 

 

Message 8 of 12
0 Kudos
Reply
G0atHax0r
Aspirant
Aspirant
‎2020-05-18 11:08 AM
‎2020-05-18 11:08 AM

Re: CM1000 intermittent connection loss on XFinity cable

I thought about factory resetting... but wasn't sure if that was going to cause me to have to work with XFinity support to get it hooked back up again, if it wasn't automatically going to be able to reconnect after the factory reset?  Any ideas?

 

Cable quality is good up to the modem... I really feel it's either cable from the street to the house, or a connector somewhere. These things don't seem to last our in the hot, humid, wet florida weather eventhough they're in a box.

 

 

@FURRYe38 wrote:

Have you factory reset the modem? 

Be sure your using good quality RG6 coax cable up to the modem. 

 

I would contact NG support and ask for additional help and information. Ask about a RMA if thats an option.

https://www.netgear.com/support/#

 

 

 

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 9 of 12
0 Kudos
Reply
FURRYe38
Guru Guru
Guru
‎2020-05-18 12:34 PM
‎2020-05-18 12:34 PM

Re: CM1000 intermittent connection loss on XFinity cable

Resets are ok. They only reset the modem and don't deactivate the ISP side. The ISP just has the mac address associated with there services. You can factory reset or reboot the modem all day long. ISP doesn't care. 


Have a friend or family member you can take the modem to and connect it at a different location to see if the problem follows? 

Message 10 of 12
0 Kudos
Reply
G0atHax0r
Aspirant
Aspirant
‎2020-05-29 11:55 AM
‎2020-05-29 11:55 AM

Re: CM1000 intermittent connection loss on XFinity cable

So here's an update to my situation... it seems that @Googalabosh was experiencing similar issues, so I'll write down my findings/experience here...

 

1.) XFinity tech came out and ran tests from the entry point to my CM1000 cable modem - no problems (and no, there are no splitters... it's a straigh run)

2.) XFinity tech ran a test from the entry point to the junction box at the street - no problem.

3.) XFinity tech ran a test from the junction box at the street, to the nearest node - again, no problems... 

 

He said everything according to his readings were within parameters and nothing looked abnormal.  This was frustrating both to me and him, since we couldn't pinpoint anything weird.  I asked him if he could put a network monitor on our account, which he was happy to do -- and I would *recommend* you asking for this same thing.  This will give them detailed reports of when things misbehave, which is what I suspect happened in my case.

 

After the tech left, my device continued to drop for the next few days off and on throughout the day... then, things stabilized.  My connection has not dropped for almost 4 days straight now., which is unheard of.  🙂  The tech said he or someone else would call back and give an update, but I have not heard anything yet.  I will definitely find out what the problem was, but I suspect it had to do with some changes at the upstream node.

 

I started keeping careful track of what my modem stats were looking like throughout the day, and found that if the downstream channels power dropped below -4.5 or -5 dBmV, which also seems to drop the SNR/MER to below 36dB, then I would start accumulating more and more uncorrectable codewords, including drops.  Since they did something on their end, my power has remained around -2 or -3dBmV and the SNR/MER remains at 40dB on average... 

 

I would focus on ensuring that these values are in the middle of the range (Power should ideally be at 0dBmV and SNR/MER should ideally be at 40dB), but it fluctuates up or down... which typically is still OK, but I guess certain modems/connections are more finicky than others.  Hope this helps!

Model: CM1000|Ultra-High Speed Cable Modem—DOCSIS® 3.1 Ready
Message 11 of 12
0 Kudos
Reply
FURRYe38
Guru Guru
Guru
‎2020-05-29 12:34 PM
‎2020-05-29 12:34 PM

Re: CM1000 intermittent connection loss on XFinity cable

Looks like this was a ISP signal issue. Glad it's working now. Thankts for the details. 
Please mark your thread as solved so others will know. 


Enjoy. 

Message 12 of 12
Reply
Top Contributors
See All
Discussion stats
  • 11 replies
  • ‎2020-05-14 11:13 AM
  • 9240 views
  • 1 kudo
  • 3 in conversation
Announcements

Orbi 770 Series