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s33 with Xfinity - Drop in Download speeds, Event Log incorrect date

  • 29 December 2022
  • 3 replies
  • 283 views

Last month, I switched ISPs to Xfinity with an 800Mbps plan, but continue to use the same s33.  

I have noticed my download speed will occasionally drops to be around100Mbps, independent of whether I use the 1Gitabit or 2.5Gigabit port.  using my ORBI router statistics, I can see the WAN port drops to 100M/Full down from 1000M/Full.  To get my speed back, I have to reconnect my patch cable (CAT6) from the modem to the router to the opposite port on the modem (1 vs. 2.5Gigabit). Sometimes I have to reboot the modem as well.   Unfortunately, I don’t know exactly when this change happens so I can’t check the event logs at that specific moment. I have seen this with my previous ISP as well, so I don’t think this is specific to the ISP.  So what would cause this?  How can I resolve?

While investigating this issue, I did look at the event log to see if I can find anything unusual.  Two things I have found, but may or may not be related.

(edit: CM-MAC information removed)

  1. My event log listed a number of incorrect initialized date values (“31/12/1969”).  I tried to “Restore Factory Defaults”, but it still shows the initialized dates.  Could this be timing/sync problem causing this drop?  Or can this be safely ignored?
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    28/12/2022
    15:03:29    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:20    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:22    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:22    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:22    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:24    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    28/12/2022
    16:06:44    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:19    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:20    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:20    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:20    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:22    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:33    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:33    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:33    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    28/12/2022
    16:23:55    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:19    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:20    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:20    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:20    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:22    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:33    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:33    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:33    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    28/12/2022
    16:33:46    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:19    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:21    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:21    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:21    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:24    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:36    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:36    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:36    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    28/12/2022
    17:00:45    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:16    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:21    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:23    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:23    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:23    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:24    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:36    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:36    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:36    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    28/12/2022
    17:05:19    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:19    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:21    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:21    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:21    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:23    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    29/12/2022
    15:21:53    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:16    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:19    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:21    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:21    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:21    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:23    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:35    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    29/12/2022
    15:25:24    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    29/12/2022
    15:45:13    		 3 Failed LAN WebGUI login attempt from ***.***.***.*** on 22/12/29 at 3:45 PM.
    29/12/2022
    15:46:16    		 3 Successful LAN WebGUI login from ***.***.***.*** on 22/12/29 at 3:46 PM.
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:19    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:20    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:20    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:20    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:22    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:34    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:34    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:34    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    29/12/2022
    16:15:01    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    29/12/2022
    16:16:02    		 3 Successful LAN WebGUI login from ***.***.***.*** on 22/12/29 at 4:16 PM.
    31/12/1969
    19:00:15    		 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
    31/12/1969
    19:00:20    		 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:22    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
    31/12/1969
    19:00:22    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
    31/12/1969
    19:00:22    		 3 CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
    31/12/1969
    19:00:24    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    31/12/1969
    19:00:28    		 6 Honoring MDD; IP provisioning mode = IPv6
    31/12/1969
    19:00:36    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
    31/12/1969
    19:00:36    		 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
    31/12/1969
    19:00:36    		 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
    29/12/2022
    16:19:36    		 6 DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    29/12/2022
    16:19:43    		 3 UCD invalid or channel unusable;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
    29/12/2022
    16:20:33    		 3 Successful LAN WebGUI login from ***.***.***.*** on 22/12/29 at 4:20 PM.
    29/12/2022
    16:21:27    		 3 Successful LAN WebGUI login from ***.***.***.*** on 22/12/29 at 4:21 PM.
  1.  Comparing the Upstream powers levels from Arris vs. Xfinity: General FAQs: S33: Cable Signal Levels (force.com) vs ‎arris s33 frequent disconnect | Xfinity Community Forum, the Upstream Power for a 4 SC-QAM channel should be in the range of 45 - 51, however, Xfinity states the Upstream power should be between 35 and 51.  Mine is currently showing:  (does this matter?)
  2. Channel ID Lock Status US Channel Type Frequency Width Power
    1 Locked SC-QAM 16400000 Hz 6400000 41.3 dBmV
    2 Locked SC-QAM 22800000 Hz 6400000 41.5 dBmV
    3 Locked SC-QAM 29200000 Hz 6400000 42.0 dBmV
    4 Locked SC-QAM 35600000 Hz 6400000

    42.8 dBmV

Here is some more information about my S33. 

Hardware Version V1.0
Software Version

TB01.03.001.10_012022_212.S3

 

Appreciate the help. --Tom

 

Hello tjchmiel

                        When it comes to slow speed issue we need to test the modem directly without router to check the optimum speed of the modem and since S33 is just a cable modem so you can access internet from only one port on the modem and if you need internet rom both the Ethernet port on the modem then you need to activate both the ports by the internet service provider end.

                       The logs are Values read by technicians from the internet provider end, since the logs are what the coaxial cable transmits and the log screen on the router is the translator so can be easily read by them, the coaxial cable is owned by the Internet service provider,  so we wouldn't be able to tell you what that means.

                       If your Event Log is reporting a high volume of errors, this would indicate a potential CMTS signal issue. To troubleshoot these errors, we would like to note the current signal levels being used by your (Modem S33). Please kindly check the link below for guidance to check the cable signal level on the modem.

                           http://arris.force.com/consumers/articles/General_FAQs/S33-Cable-Signal-Levels

Let us know if this helps.

Thanks for the generic response.   Since my initial post, a Comcast technician was  at my home, and all signals are in their normal range.   

Please review my initial post, in which I asked 2 specific questions.  Reviewing the log today, I see no message other than instances of what I stated above.

 

 

 

  1. to fully compare power levels, you also need the downstream. They kind of go hand in hand. If you’re close to a hub, you’re downstream values will be higher and your upstream lower. Because the power coming in is higher (being closer) and the modem doesn’t need as much power to talk back to the hub. So its tough to judge you upstream value just off themselves. They have to be taking together with downstream. 
  2. the switching back and forth from 100/1000mbps could be a cable. The orbi’s seem a little more sensitive to sketchy cables and I’ve seen them switch from 100/1gig service before. I usually say move the modem/router right next to each other and connect with a short/high quality cat 6 cable and watch them for a period. To frequently I see sketchy cables cause the ports dropping down to 100mbps connections. 

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