Community Forum

Home internet keeps dropping everyday during work hours

dwang953
Frequent Visitor

Home internet keeps dropping everyday during work hours

Like a lot of people, I have been WFH for the past 2 months. My home internet was fine until about 1.5 weeks ago, when I started getting terrible latency on Zoom (>1000ms latency  for both audio and video) and recently the internet has been dropping completely, consistently between 1pm and 5pm local time. 

 

Behavior: 

Typically I get 150-200Mbps down and 5Mbps up. This works really well on my Google Wifi mesh network when things are working fine, the service is great. As of 1.5 weeks ago, I have been having very high latency  and slow download speeds during the afternoons. More recently, the internet has started to completely drop.  I am almost certain it's  not an issue with the routers, but rather the modem or wiring outside my apartment. When I am having issues and I power cycle/restart my modem, the internet comes back for ~5 min, and then it crashes again. The most peculiar part is that the internet always comes back full strength after around 5pm daily and I never have issues at night. 

 

My setup:

Model - Motorola MG7315 8x4 Cable Modem

Routers - two Google Wifi 1st gen mesh network routers 

 

Here is the stats from my modem (at night, when the internet is  working fine): 

Downstream Bonded Channels		 	
  
   Channel	Lock Status	Modulation	Channel ID	Freq. (MHz)	Pwr (dBmV)	SNR (dB)	Corrected	Uncorrected
1	Locked	QAM256	8	471.0	3.9	41.3	28	0
2	Locked	QAM256	9	477.0	3.7	41.9	31	0
3	Locked	QAM256	10	483.0	3.9	42.0	31	0
4	Locked	QAM256	11	489.0	4.2	41.9	38	0
5	Locked	QAM256	12	495.0	4.2	41.9	27	0
6	Locked	QAM256	13	507.0	4.0	41.7	52	0
7	Locked	QAM256	14	513.0	3.7	41.8	55	0
8	Locked	QAM256	15	519.0	3.3	41.4	48	0
Total	 	 	 	 	 	 	310	0

 

I also ran a traceroute (again at night, when the internet is working fine): 

Traceroute has started…

traceroute to 8.8.8.8 (8.8.8.8), 64 hops max, 72 byte packets
 1  testwifi.here (192.168.86.1)  8.865 ms  4.189 ms  4.873 ms
 2  192.168.0.1 (192.168.0.1)  4.906 ms  4.228 ms  8.991 ms
 3  96.120.89.157 (96.120.89.157)  41.908 ms  43.281 ms  43.313 ms
 4  96.110.179.13 (96.110.179.13)  43.993 ms  41.227 ms  47.349 ms
 5  po-2-rur01.sffolsom.ca.sfba.comcast.net (69.139.198.5)  42.966 ms  36.266 ms  14.658 ms
 6  be-209-rar01.santaclara.ca.sfba.comcast.net (68.85.57.241)  16.111 ms  16.443 ms  16.328 ms
 7  be-299-ar01.santaclara.ca.sfba.comcast.net (68.86.143.93)  16.776 ms  15.206 ms  13.515 ms

And finally, here is the Event log from my modem. Note that this log does include times when I had really bad/dropped connections and includes multiple modem restarts I performed:

   Log		 	
  
 Time 	 Priority 	 Description 
 Time Not Established 	 Critical (3) 	 No Ranging Response received - T3 time-out;CM-MAC=00:40:36:4... 
 Thu May 07 23:56:23 2020  	 Critical (3) 	 Started Unicast Maintenance Ranging - No Response received -... 
 Mon May 11 00:37:13 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 00:37:28 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 00:37:29 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire FEC ... 
 Mon May 11 00:41:13 2020  	 Critical (3) 	 Received Response to Broadcast Maintenance Request, But no U... 
 Mon May 11 12:48:56 2020  	 Critical (3) 	 Resetting the cable modem due to docsDevResetNow 
 Time Not Established 	 Critical (3) 	 No Ranging Response received - T3 time-out;CM-MAC=00:40:36:4... 
 Mon May 11 13:58:38 2020  	 Critical (3) 	 Resetting the cable modem due to docsDevResetNow 
 Time Not Established 	 Critical (3) 	 No Ranging Response received - T3 time-out;CM-MAC=00:40:36:4... 
 Time Not Established 	 Notice (6) 	 Honoring MDD; IP provisioning mode = IPv6 
 Mon May 11 20:03:50 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:03:50 2020  	 Warning (5) 	 MDD message timeout;CM-MAC=00:40:36:4a:af:b8;CMTS-MAC=00:01:... 
 Mon May 11 20:03:57 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:03:57 2020  	 Warning (5) 	 MDD message timeout;CM-MAC=00:40:36:4a:af:b8;CMTS-MAC=00:01:... 
 Mon May 11 20:06:26 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:06:26 2020  	 Critical (3) 	 Received Response to Broadcast Maintenance Request, But no U... 
 Mon May 11 20:07:01 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:07:01 2020  	 Critical (3) 	 Received Response to Broadcast Maintenance Request, But no U... 
 Mon May 11 20:07:20 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:07:20 2020  	 Warning (5) 	 MDD message timeout;CM-MAC=00:40:36:4a:af:b8;CMTS-MAC=00:01:... 
 Mon May 11 20:07:30 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:07:30 2020  	 Critical (3) 	 Received Response to Broadcast Maintenance Request, But no U... 
 Mon May 11 20:07:45 2020  	 Critical (3) 	 SYNC Timing Synchronization failure - Failed to acquire QAM/... 
 Mon May 11 20:07:59 2020  	 Critical (3) 	 Received Response to Broadcast Maintenance Request, But no U... 
 Mon May 11 20:08:17 2020  	 Notice (6) 	 Honoring MDD; IP provisioning mode = IPv6 
 Mon May 11 20:08:29 2020  	 Warning (5) 	 ToD request sent - No Response received;CM-MAC=00:40:36:4a:a... 
 	 	 
   	 	 
EG
Expert

Re: Home internet keeps dropping everyday during work hours

The downstream stats are good. What do the upstream power levels look like ?



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
dwang953
Frequent Visitor

Re: Home internet keeps dropping everyday during work hours

Here is the upstream data (again this is while the internet is working fine; i'll try to  capture again if i have service drops later today): 

 

  Upstream Bonded Channels		 	
  
   Channel	Lock Status	Channel Type	Channel ID	Symb. Rate (Ksym/sec)	Freq. (MHz)	Pwr (dBmV)
1	Locked	ATDMA	4	5120	35.6	44.8
2	Locked	ATDMA	3	5120	29.2	45.0
3	Locked	ATDMA	5	1280	40.4	45.0
4	Locked	ATDMA	2	5120	22.8	45.3

 

 

dwang953
Frequent Visitor

Re: Home internet keeps dropping everyday during work hours

I'm starting to have some service stability issues now and this is what a ping test looks like: 

 

Ping has started…

PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=0 ttl=53 time=249.568 ms
64 bytes from 8.8.8.8: icmp_seq=1 ttl=53 time=246.819 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=53 time=486.781 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=53 time=567.907 ms
Request timeout for icmp_seq 4
Request timeout for icmp_seq 5
Request timeout for icmp_seq 6
Request timeout for icmp_seq 7
Request timeout for icmp_seq 8
64 bytes from 8.8.8.8: icmp_seq=5 ttl=53 time=4674.579 ms
Request timeout for icmp_seq 10
Request timeout for icmp_seq 11
64 bytes from 8.8.8.8: icmp_seq=12 ttl=53 time=726.842 ms
Request timeout for icmp_seq 13
Request timeout for icmp_seq 14
Request timeout for icmp_seq 15
64 bytes from 8.8.8.8: icmp_seq=16 ttl=53 time=249.871 ms
64 bytes from 8.8.8.8: icmp_seq=17 ttl=53 time=43.935 ms
64 bytes from 8.8.8.8: icmp_seq=18 ttl=53 time=29.662 ms
64 bytes from 8.8.8.8: icmp_seq=19 ttl=53 time=18.967 ms
64 bytes from 8.8.8.8: icmp_seq=20 ttl=53 time=35.252 ms
64 bytes from 8.8.8.8: icmp_seq=21 ttl=53 time=31.772 ms
64 bytes from 8.8.8.8: icmp_seq=22 ttl=53 time=34.824 ms
64 bytes from 8.8.8.8: icmp_seq=23 ttl=53 time=32.078 ms
64 bytes from 8.8.8.8: icmp_seq=24 ttl=53 time=42.895 ms
64 bytes from 8.8.8.8: icmp_seq=25 ttl=53 time=29.476 ms
64 bytes from 8.8.8.8: icmp_seq=26 ttl=53 time=59.585 ms
64 bytes from 8.8.8.8: icmp_seq=27 ttl=53 time=21.061 ms
64 bytes from 8.8.8.8: icmp_seq=28 ttl=53 time=29.832 ms
64 bytes from 8.8.8.8: icmp_seq=29 ttl=53 time=17.727 ms
64 bytes from 8.8.8.8: icmp_seq=30 ttl=53 time=78.030 ms
64 bytes from 8.8.8.8: icmp_seq=31 ttl=53 time=38.353 ms
64 bytes from 8.8.8.8: icmp_seq=32 ttl=53 time=116.759 ms
64 bytes from 8.8.8.8: icmp_seq=33 ttl=53 time=122.307 ms
64 bytes from 8.8.8.8: icmp_seq=34 ttl=53 time=255.774 ms
64 bytes from 8.8.8.8: icmp_seq=35 ttl=53 time=164.712 ms
64 bytes from 8.8.8.8: icmp_seq=36 ttl=53 time=151.867 ms
64 bytes from 8.8.8.8: icmp_seq=37 ttl=53 time=100.017 ms

as  well as a traceroute: 

Traceroute has started…

traceroute to 8.8.8.8 (8.8.8.8), 64 hops max, 72 byte packets
 1  testwifi.here (192.168.86.1)  5.233 ms  5.036 ms  4.242 ms
 2  192.168.0.1 (192.168.0.1)  6.474 ms  4.730 ms  4.257 ms
 3  96.120.89.157 (96.120.89.157)  83.709 ms  48.184 ms  51.116 ms
 4  96.110.179.13 (96.110.179.13)  38.532 ms  24.385 ms  18.673 ms
 5  po-2-rur01.sffolsom.ca.sfba.comcast.net (69.139.198.5)  34.795 ms  27.142 ms  27.309 ms
 6  be-209-rar01.santaclara.ca.sfba.comcast.net (68.85.57.241)  31.344 ms  32.112 ms  27.977 ms
 7  be-299-ar01.santaclara.ca.sfba.comcast.net (68.86.143.93)  21.301 ms  28.676 ms  17.398 ms
 8  96.112.146.26 (96.112.146.26)  27.848 ms  29.406 ms  22.281 ms
 9  72.14.239.204 (72.14.239.204)  29.250 ms  31.880 ms  24.040 ms
10  209.85.247.55 (209.85.247.55)  27.318 ms  36.514 ms  53.049 ms
11  dns.google (8.8.8.8)  61.557 ms  53.650 ms  67.812 ms
Daniel15au
Frequent Visitor

Re: Home internet keeps dropping everyday during work hours

I'm having exactly the same issue, and based on your traceroute it looks like you're also in the Bay Area. I imagine the connections are very congested here given so many people are working from home.

I've got the 175 Mb/s plan and it's fine at night and early in the morning, but during the day it's so slow to the point where I need to use "mobile hotspot" on my phone to get a usable connection. I'm using Ethernet so it's not a wifi problem. This has been happening since the start of April and Comcast support have not been helpful in resolving it at all.

Good luck.

dwang953
Frequent Visitor

Re: Home internet keeps dropping everyday during work hours

Wow ok, sounds like the same EXACT problem. Yes, I'm in the Bay Area - San Francisco, specifically. Ialsopay for the 175Mbps package from Xfinity. Internet is stable and fast in morning hours (e.g. before 12pm) and at night (after ~6pm). 

 

I could definitely see this just as overall platform congestion since a ton of tech workers are presumably all WFH and on high bandwidth programs like videoconferencing. The only odd thing for me is that things seemed to be OK until only ~2 weeks ago, but the WFH situation has  been going on since March...   

 

@Daniel15au does your service just get really slow or do you get dropped connections? 

EG
Expert

Re: Home internet keeps dropping everyday during work hours

@dwang953 

 

The upstream power is good as well but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) somewhere.

 

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

 

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
dwang953
Frequent Visitor

Re: Home internet keeps dropping everyday during work hours

@EG thank you so much! from your expertise (and fully knowing I have only provided limited data/information), do you think the issue could be with my modem? I was thinking of buying a new modem with more channels/RAM to just test and rule out the modem as an issue, but don't feel that the issues I have observed necessarily support the hypothesis that the modem is at fault? 

 

from all my research, i also feel like it could be an ingress issue, but outside of my apartment unit. for context, I live in a small apartment building in the city that has 7 separate apartment units. I'm assuming the xfinity line comes into the building and then there's a bunch of splitters to the individual units? i'm worried there could be leakage/connection issues on one of the lines leading to a unit other than mine, which might be causing issues that are difficult to diagnose. 

EG
Expert

Re: Home internet keeps dropping everyday during work hours


@dwang953 wrote:

I was thinking of buying a new modem with more channels/RAM to just test and rule out the modem as an issue, but don't feel that the issues I have observed necessarily support the hypothesis that the modem is at fault? 

 

Anything is possible but looking at those RF signal errors, it is much more likely to be a line / connection quality impairment rather than a modem hardware issue. 


 



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
ComcastJoeTru
Official Employee

Re: Home internet keeps dropping everyday during work hours

Hello dwang953. We appreciate you visiting and posting on our Forums. I can assist with further troubleshooting your internet speed / connectivity issues. Please reach out to me via private message and include your full name so I can assist you. To send a private message: click my name (ComcastJoeTru) to view my profile. Then click the link that says "Send a message" and there you can private message me. 



I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
ah365
Frequent Visitor

Re: Home internet keeps dropping everyday during work hours

it looks like comcast has network congestion everywhere, my entire neighborhood has the exact problem due to network congestion , the problem disappears at night as well.