U

Visitor

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14 Messages

Mon, Sep 13, 2021 9:20 AM

Internet drop frequently

I'm using my own equipment with Xfinity 1Gbps service.  My connection is dropping frequently.  Typical drops are fairly short in duration, let's say 30-60 seconds.  I feel like the dropping started after hurricane Ida passed through the area and caused some major local flooding.  I'm using a Motorola MB8611 along with 2 Linksys Velop mesh devices.  The Linksys devices are connected with ethernet.  I've called Xfinity support and they've done the typical "sending a signal" to the modem stuff.  I've reset the MB8611 to factory and reactivated it.  I've powered cycled everything numerous times.  I'm unable to reach the modem on http://192.168.100.1 and nmap shows that ports 80 and 443 are filtered.  When the connection is up, I get great speeds...Linksys devices indicates 943 Mbps down, 42 Mbps up and latency of 9 ms.  Without access to any signal metrics from the MB8611, what can I do to troubleshoot this?  I'm sure if I call support, they'll just "send signals" all day long and tell me this is a 3rd party issue.  

Visitor

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1 Message

1 m ago

Ours went out during storm August 27. They came to the house and said it was our equipment. We bought a new router and modem. It works but our service goes out multiple times a day. It usuallywon't start working again until I unplug it. Very frustrating. 

EG

Expert

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89.8K Messages

@user_cd999d

Please create a new topic of your own here on this board detailing your issue, thanks. 

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EG

Expert

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89.8K Messages

1 m ago

@user_e21a1a 

Try connecting a computer directly to the MB8611 and see if you can then reach the user interface pages.

Visitor

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14 Messages

1 m ago

Will do.  I just finished running a few cables in order to facilitate this.  I'm also trying to eliminate as much cable and as many couplers in the mix.  I'll get to the direct modem connection later today I hope.  Also want to eliminate the Linksys equipment as a possible source of trouble.  I did have quite a few headaches early on with that stuff, but the Wifi appears to be stable. Lights on the Linksys devices indicate that all is ok, but Internet connection has failed.

I'll try to follow up this evening.  Thank you.

Visitor

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14 Messages

1 m ago

I'll add one odd thing into the mix here as well...my wife and I own a store on the same street that our residence is on and there are frequent drops at the shop as well.  Not as often, but troublesome enough.  Makes we wonder if there's something systemic up in the wires on our street.

Visitor

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1 Message

1 m ago

internet keeps going off line   since the day we signed up  and yall been out to our home at least 7 times already and still dropping 

EG

Expert

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89.8K Messages

@user_9c9e10

Please create a new topic of your own here on this board detailing your issue and I will attempt to assist you there. Please do not hijack someone else's help thread in progress. Multiple posters piling on to and being helped in a single thread becomes too complicated. confusing, and convoluted. And it's unfair to the original poster.Thank you. 
 

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Abom

Frequent Visitor

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7 Messages

1 m ago

how's the pole to drop strength? we had a bunch of issues with a long drop from the pole to the house, and some pretty length runs in the home. Commscope amp at the drop resolved it completely.

https://www.xfinity.com/support/articles/drop-amplifiers

Visitor

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14 Messages

I hope I can get some signal metrics later tonight once I connect directly to the modem.  I've been working to reduce the length of the cable run.  Right now, it's pole to moca filter on a ground block in the cable box on the side of the house to maybe 6ft to a coupler to 20 ft to the modem.  Cable runs are short.  I can't imagine that there's much loss between the pole and the modem right now.  Xfinity installer measured the signal with additional cable in the mix and said it was good back in April or May.

EG

Expert

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89.8K Messages

@Abom

FWIW, they stated this: "I'm unable to reach the modem on http://192.168.100.1"

They can't see their signal "strength" because they currently can't access the modem's user-interface pages.

(edited)

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Visitor

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14 Messages

1 m ago

OK!  I was finally able to find a few moments of internet quiet in order to grab the modem info.  Here's what I found:

Software

   Device Information

   Cable Specification Version DOCSIS 3.1

  

   Hardware Version V1.0

  

   Software Version 8611-19.2.18

  

   Cable Modem MAC Address XX:XX:XX:XX:XX:XX

  

   Cable Modem Serial Number

  

   CM Certificate Installed

  

   Prod_19.2_d31

 

  Event Log  

  

   Time  Priority  Description

   Time Not Established

  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

   Time Not Established

  Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   Time Not Established

  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

   Time Not Established

  Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:06:11

Mon Sep 13 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   Time Not Established

  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

   Time Not Established

  Notice (6) Honoring MDD; IP provisioning mode = IPv6

   09:16:34

Mon Sep 13 2021 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:16:34

Mon Sep 13 2021 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:17:37

Mon Sep 13 2021 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:17:37

Mon Sep 13 2021 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=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:18:12

Mon Sep 13 2021 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:19:02

Mon Sep 13 2021 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   09:19:02

Mon Sep 13 2021 Warning (5) Dynamic Range Window violation

   16:46:05

Mon Sep 13 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:46:05

Mon Sep 13 2021 Warning (5) MDD message timeout;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:46:11

Mon Sep 13 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:46:11

Mon Sep 13 2021 Warning (5) MDD message timeout;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:46:47

Mon Sep 13 2021 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:47:17

Mon Sep 13 2021 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=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:47:17

Mon Sep 13 2021 Notice (6) CM-STATUS message sent. Event Type Code: 23; Chan ID: 37; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

   16:47:17

Mon Sep 13 2021 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 2 3.;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.1;

Visitor

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14 Messages

1 m ago

I should also add that I'm an internet only customer though the pricing was best with a bundle of some sort that included phone, etc.  As far as I can tell, there are only simple barrel connectors on the line on the other side of the moca filter thats in the cable box outside the house on a grounding plate.  I may be able to replace the entire length of cable that runs from the house side of the moca filter to the modem with new cable if that helps.

Visitor

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14 Messages

1 m ago

I noticed that the power on the downstream channels was fairly high so I put a -3.5 dBmV splitter at the POE to bring those values down to see if that helps.

EG

Expert

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89.8K Messages

@user_e21a1a

Right. You don't need a drop amp. Quite the contrary. The downstream power is very strong. And the SNR's and the upstream power levels are good.

Instead of using a splitter as an overall attenuator (it can actually make things worse), you should use the correct tool for the job. Such as this;

https://www.amazon.com/line-Signal-Forward-Attenuator-FPA6-54/dp/B07882H96R

And 3.5 dB is not enough. And, a splitter will also affect the upstream power (make it higher) which is something that you don't want to do in this case. The attenuator that I linked to is an FPA (Forward Path 'only' Attenuator). It will knock down the downstream power level by 6dB, but it will not affect the upstream power which is already in the *sweet spot*.

(edited)

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Visitor

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14 Messages

That's fantastic! I appreciate your help.  I did some testing with the splitter just to see if there was a difference.  I was able to run a persistent ping for a few hours and lost only 6 out of 11,953 packets.  That would have been impossible previously, so there's been some progress.  I just placed my order!  Thank you again.  I'll follow up on this thread once I have the FPA in place.

EG

Expert

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89.8K Messages

Please do ! 🙂

.................................

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? Please mark an Accepted Answer!tick

Visitor

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14 Messages

1 m ago

I received my FPA this afternoon and just finished installing it.  I grabbed some before/after metrics while I was at it.  My before metrics are with a -3.5 dBmV splitter at POE because I forgot that I had it there!  If it's meaningful to anyone, I can always remove the splitter and check to see what the numbers are without the FPA.  My current setup has 2 simple barrel connectors on the cable from the POE to the modem.  That cable run is 35-45 ft.  I installed the FPA directly on the modem.  I don't have any other devices cable devices in the house right now and I figured I'd go directly to the source of my issues.

Before FPA with Splitter on the cable:

FPA only: 
Speed check as reported by node connected to modem:

  

EG

Expert

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89.8K Messages

@user_e21a1a

Remove the splitter and use only the FPA. 

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? Please mark an Accepted Answer!tick

Visitor

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14 Messages

1 m ago

Sorry if my post wasn't clear!  I only had the splitter on for the pre FPA metrics in that post.  I removed the splitter and only have the FPA for the final metrics above and that's the configuration I have been running since adding that post.  So far, so good!  0 hiccups!

EG

Expert

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89.8K Messages

1 m ago

The upstream power is still on the high side. There's no wiggle room to allow for any possible intermittent fluctuations. It will be o/k if it remains stable. Good luck !

Visitor

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14 Messages

@EG What would be the proper way to attenuate the upstream power? 

Visitor

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14 Messages

I'll also confirm that those metrics are the correct ones.  It's strange that the upstream metrics are different than my original.  I'm starting to think that I may have attached the wrong screen shot.  I'm going to do them over once I get back to the house.  Thank you again!

EG

Expert

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89.8K Messages

No prob !

..........................

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? Please mark an Accepted Answer!tick

Visitor

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14 Messages

1 m ago

Looks like I attached the wrong screen shots to my final configuration!  Upstream and downstream are ok now with a little bit of wiggle room, right?

EG

Expert

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89.8K Messages

1 m ago

You're golden !

............................

Visitor

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14 Messages

1 m ago

I'm marking this Accepted.  The line has been running clean and things are looking good!  Thanks again.

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