MB8611 drops connection at least 1-2 times per day

Please post the entire error log entry table but redact any and all CM and CMTS MAC addresses.

Please copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

Here is the modem data:

Event Log

Time    Priority    Description      Time Not Established   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     02:35:38 Tue May 7 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:32:46 Wed May 8 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:32:52 Wed May 8 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:30 Wed May 8 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:30 Wed May 8 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:31 Wed May 8 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:31 Wed May 8 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:31 Wed May 8 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:31 Wed May 8 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:36 Wed May 8 2024   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:33:36 Wed May 8 2024   Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     08:42:17 Thu May 9 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     04:42:10 Fri May 10 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     16:42:45 Fri May 10 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     17:20:06 Fri May 10 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     17:37:40 Fri May 10 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     01:19:55 Sat May 11 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     02:09:23 Mon May 13 2024   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=XX;CMTS-MAC=YY;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;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     Time Not Established   Notice (6)   Honoring MDD; IP provisioning mode = IPv6     08:54:19 Tue May 14 2024   Notice (6)   DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     09:55:41 Tue May 14 2024   Warning (5)   RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=XX;CMTS-MAC=YY;CM-QOS=1.1;CM-VER=3.1;     09:55:41 Tue May 14 2024   Warning (5)   Dynamic Range Window violation

Downstream Bonded Channels

Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected    1 Locked QAM256 20 543.0 -13.1 37.7 17 0    2 Locked QAM256 13 501.0 -13.0 37.8 37 0    3 Locked QAM256 14 507.0 -13.2 37.7 36 0    4 Locked QAM256 15 513.0 -13.0 37.8 12 0    5 Locked QAM256 16 519.0 -13.1 37.8 32 1    6 Locked QAM256 17 525.0 -13.1 37.8 27 8    7 Locked QAM256 18 531.0 -13.0 37.9 33 0    8 Locked QAM256 19 537.0 -13.1 37.8 26 0    9 Locked QAM256 21 555.0 -13.1 37.6 26 0    10 Locked QAM256 22 561.0 -13.0 37.7 31 0    11 Locked QAM256 23 567.0 -12.8 37.8 34 5    12 Locked QAM256 24 573.0 -13.0 37.7 27 6    13 Locked QAM256 25 579.0 -12.9 37.8 30 0    14 Locked QAM256 26 585.0 -12.8 37.8 24 0    15 Locked QAM256 27 591.0 -12.9 37.8 22 0    16 Locked QAM256 28 597.0 -13.1 37.7 4 0    17 Locked QAM256 29 603.0 -12.7 37.9 18 0    18 Locked QAM256 30 609.0 -12.6 38.0 24 9    19 Locked QAM256 31 615.0 -12.5 38.0 9 0    20 Locked QAM256 32 621.0 -12.2 38.2 4 0    21 Locked QAM256 33 627.0 -12.3 38.1 1 0    22 Locked QAM256 34 633.0 -12.4 38.2 22 0    23 Locked QAM256 35 639.0 -12.5 38.2 1 0    24 Locked QAM256 36 645.0 -12.2 38.4 9 0    25 Locked QAM256 37 651.0 -12.2 38.4 20 0    26 Locked QAM256 38 657.0 -12.2 38.5 1 0    27 Locked QAM256 39 663.0 -12.2 38.4 3 0    28 Locked QAM256 40 669.0 -12.6 38.2 16 0    29 Locked QAM256 41 675.0 -12.8 37.6 8 0    30 Locked QAM256 42 681.0 -12.5 38.4 2 0    31 Locked QAM256 43 687.0 -12.3 38.5 21 0    32 Locked QAM256 44 693.0 -12.2 38.4 2 0    33 Locked OFDM PLC 193 702.0 -12.3 37.2 43410215 0

Upstream Bonded Channels

Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)    1 Locked SC-QAM 1 5120 16.4 51.3    2 Locked SC-QAM 2 5120 22.8 51.8    3 Locked SC-QAM 3 5120 29.2 52.5    4 Locked SC-QAM 4 5120 35.6 52.5    5 Locked SC-QAM 5 2560 40.4 54.0    6 Locked SC-QAM 6 2560 10.4 50.0

Both the downstream and the upstream power levels are out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

Good luck with it !

So speaking with Xfinity support and they are telling me that my modem is not compatible with my internet package.

I'm currently subscribed to

EXTREME PRO INTERNET

Speeds up to 1000 Mbps / 20 Mbps

Does this seem correct? Could that be causing the drops?

If so, can you recommend a 3rd party modem I can purchase vs renting from Xfinity?

Nah. They are wrong..... The 8611 is approved for that speed tier. And even if it wasn't, it couldn't cause the signals to be out of spec. There is an obvious connection quality problem. If none of those tips apply, then yes, you'll need a tech out to investigate and correct it as was stated. Good luck and please post back with how things turn out.

So after a few months, the upstream and downstream signals are good but I'm still having an issue with the modem rebooting at least 1-2 times per day.

Is there an issue with this modem? Can anyone recommend either Netgear CM2050V or ARRIS S33?

Those two modems are on the Comcast approved list.

The downstream power looks good now but the upstream power is still too high. What has been done since ? Did you try any of those tips ? Did you get a tech visit ?

A tech came out to house and confirmed that the issue is the feed from the street being low. He was going to escalate.

Besides that, I've gotten zero communication from Comcast.

Just keep emailing and every now and then a truck drives around the neighborhood, so I have no idea what has been done, just noticed levels were different. 

I'll have to keep harassing them. What should the upstream range be? 

Around 40 dB would be ideal. I would hold off on changing the modem. No matter what modem you use, the line impairment will still be there. He should have escalated it but many times they don't..... You're going to have to get the techs involved again.

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may indeed lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.

Good luck !