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Loosing internet several times in last couple of days - Xfinity service or hardware issue?

Contributor

Loosing internet several times in last couple of days - Xfinity service or hardware issue?

In the past three days I've lost internet access 4 or 5 times.  Ususlly just for a minute of two.  Today for about an hour.  After a Gateway reboot (sometims 2X) brings it back.

Gateway make: Arris SBG6782-AC

I have not had any contact with Xfinity support (yet).  I hoped to get some feedback here, first.

Xfinity My Account says "no problem with internet service".

Lights on gateway are OK/correct.

Ethernet (from my PC) shows connected/no internet access.

WiFi is down during outage.

Log below

 

Status - Event Log

The table below contains the log of events that the SBG6782-AC has detected. This log can be important to the service provider to help diagnose and correct problems, if any should occur.

 
Time Priority Description
Sat Feb 03 12:01:10 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INIT
Sat Feb 03 08:02:37 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Sat Feb 03 00:00:17 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 23:52:36 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Fri Feb 02 16:02:26 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 08:00:22 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 08:00:21 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 07:52:39 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 00:49:56 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 00:39:51 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 00:00:20 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 00:00:19 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Fri Feb 02 00:00:16 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 23:52:34 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 19:19:14 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 16:43:56 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 16:42:23 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 15:52:27 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 15:52:25 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 15:52:24 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 15:01:48 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 10:59:36 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 09:50:00 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 07:52:29 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 07:52:28 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 07:52:26 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 01:05:11 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 00:53:34 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 00:53:32 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 00:53:31 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Thu Feb 01 00:00:12 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;
Wed Jan 31 23:52:30 2018 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=90:b1:34:c7:06:2c;CMTS-MAC=00:01:5c:74:44:4e;CM-QOS=1.1;CM-VER=3.0;

 

Diamond Problem Solver

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

Also post the signal stat figures;

 

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.






Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


@ wrote:

Also post the signal stat figures;

 

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.







Sorry, I hate to be "that guy", but I don't see anywhere on the Arris control panel those numbers.  Any suggestions on where I could find them would be appreciated.

Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


@ wrote:

Also post the signal stat figures;

 

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.







Found it:

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 13 567000000 Hz -4.0 dBmV 37.5 dB 0 0
2 Locked QAM256 14 573000000 Hz -4.2 dBmV 37.5 dB 0 0
3 Locked QAM256 16 585000000 Hz -4.4 dBmV 37.5 dB 0 0
4 Locked QAM256 17 591000000 Hz -4.3 dBmV 37.8 dB 0 0
5 Locked QAM256 18 597000000 Hz -3.9 dBmV 37.8 dB 0 0
6 Locked QAM256 19 603000000 Hz -3.5 dBmV 37.8 dB 0 0
7 Locked QAM256 20 609000000 Hz -3.4 dBmV 37.9 dB 0 0
8 Locked QAM256 22 621000000 Hz -3.3 dBmV 37.8 dB 0 0

 

 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 2 5120 Ksym/sec 29400000 Hz 46.0 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 35800000 Hz 44.5 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 23000000 Hz 46.5 dBmV



Diamond Problem Solver

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

They were o/k at that moment. You stated that "the WiFi" is down when it happens. Are wired connections also down ?

Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


@ wrote:

They were o/k at that moment. You stated that "the WiFi" is down when it happens. Are wired connections also down ?


First, thanks for the feedback.  Just a recap: I'm trying to insure that my Arris gateway isn't faulty before leaving for a month. Your feedback has already been very helpful.

In response to your question, ethernet connection from my PC showed "connected but internet not available"...

I'm beginning to believe that the issue is Xfinity internet disruptions here....

Diamond Problem Solver

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


wrote:

I'm beginning to believe that the issue is Xfinity internet disruptions here....


It could be or it could be the device. I've seen posts here indicating firmware glitches along these lines.

Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


@ wrote:

wrote:

I'm beginning to believe that the issue is Xfinity internet disruptions here....


It could be or it could be the device. I've seen posts here indicating firmware glitches along these lines.


How to diagnose further?

Diamond Problem Solver

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

Swap the device out ?

Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


@ wrote:

Swap the device out ?


I thought I'd provide an update.  While I'm not opposed to buying a new gateway, I don't want to waste my money if that's not the issue. 

Saturday I initiated a chat session with Xfinity support.  They ran a couple of checks and did remote reboot of my gateway.  Agent said everything looked OK on their end.  They said if I wanted more help/feedback regarding the numerous errors I'd have to call back this morning (2/5).

This morning I called Xfinity support and they ran the same checks and tests, again, and said (again) that everything looked OK on their end.  This time the Xfinity support person said that if I wanted additional help to contact my equipment manufacturer (Arris).  

I got on a chat with Arris, and the support quickly identified that the Upstream Bonded Channel power on channel 2 was below minimum sped.  44.3 dBmV versus spec min of 45.0.  He indicated that this was likely an Xfinity issue and to contact them.  When I explained my previous conversation with Xfinity he said that they always send their customers to Arris for support even when it's their issue.

So, I opened another chat with Xfinity about the out of spec power level on the upstream bonded channels.  Agent immediatly agreed to send a tech to my house for trouble shooting.  Scheduled for Friday, 2/9.

I'll update this again when I have more info.

Thanks for your help so far.

Expert

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


I got on a chat with Arris, and the support quickly identified that the Upstream Bonded Channel power on channel 2 was below minimum sped.  44.3 dBmV versus spec min of 45.0. 


Where do they find these people? 44.3 dBmv is in spec. Also, no modem is sensitive enough to give very accurate readings, they are generally +/- 3db. So 44.3 is exactly the same as 45.0 for all practical purposes.

 

I like EG's advice.

 

 


I am not a Comcast employee, just a moderator. Pls observe Wheaton's Law.
Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

Arris customer support.
Diamond Problem Solver

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

Thank for answering nerd. Smiley Happy

Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

OK.  I swapped out the device with a Comcast XB3 (Arris TG1682G).  Power and SNR below:

 

Downstream
Channel Bonding Value
Index
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Lock Status
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Not Locked
Not Locked
Not Locked
Not Locked
Not Locked
Not Locked
Not Locked
Not Locked
Frequency
657.00 MHz
495.00 MHz
501.00 MHz
507.00 MHz
513.00 MHz
519.00 MHz
525.00 MHz
531.00 MHz
537.00 MHz
543.00 MHz
549.00 MHz
555.00 MHz
561.00 MHz
567.00 MHz
573.00 MHz
591.00 MHz
597.00 MHz
603.00 MHz
609.00 MHz
621.00 MHz
627.00 MHz
633.00 MHz
645.00 MHz
651.00 MHz
               
SNR
35.08 dB
36.61 dB
36.61 dB
36.39 dB
36.61 dB
36.61 dB
36.39 dB
36.39 dB
36.39 dB
35.78 dB
35.60 dB
35.60 dB
34.93 dB
34.93 dB
34.93 dB
35.08 dB
35.60 dB
35.60 dB
35.60 dB
35.78 dB
35.78 dB
35.60 dB
34.93 dB
35.60 dB
               
Power Level
-6.70 dBmV
-1.60 dBmV
-1.90 dBmV
-2.30 dBmV
-2.60 dBmV
-2.60 dBmV
-2.70 dBmV
-3.10 dBmV
-3.90 dBmV
-4.10 dBmV
-4.80 dBmV
-5.20 dBmV
-5.80 dBmV
-6.30 dBmV
-6.10 dBmV
-5.80 dBmV
-5.70 dBmV
-5.40 dBmV
-5.50 dBmV
-5.60 dBmV
-5.30 dBmV
-4.90 dBmV
-6.60 dBmV
-6.80 dBmV
               
Modulation
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
               
Upstream
Channel Bonding Value
Index
1
2
3
4
5
6
7
8
Lock Status
Locked
Locked
Locked
Not Locked
Not Locked
Not Locked
Not Locked
Not Locked
Frequency
23.00 MHz
29.40 MHz
35.80 MHz
         
Symbol Rate
5120 KSym/s
5120 KSym/s
5120 KSym/s
         
Power Level
46.50 dBmV
45.50 dBmV
43.75 dBmV
         
Modulation
64 QAM
64 QAM
64 QAM
         
Channel Type
DOCSIS2.0 (ATDMA)
DOCSIS2.0 (ATDMA)
DOCSIS2.0 (ATDMA)
 
Contributor

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?


@ wrote:

Swap the device out ?


That fixed the issue.  Thank you for your help.

Diamond Problem Solver

Re: Loosing internet several times in last couple of days - Xfinity service or hardware issue?

Happy surfing !