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Another Gigabit subscriber not getting faster than 250MB/s

Reciprocity75
New Poster

Another Gigabit subscriber not getting faster than 250MB/s

I have been paying for gigabit internet for over a year and have never acheived anything close. Lately I have been getting maxed out at around 250MB/s. This is on wired and wireless connected to my router. I have tried all of the suggestions listed in these forums, called Comcast 3 times, etc. On the last phone call the support agent told me my modem, being installed in 2018, was now old enough that it needed to be replaced. It is an Arris SB8200. Needless to say I was less than impressed with the 3 support agents who all read from the exact same script with no ability or offer to escalate. For 90% of the issues, they are sure to help, but for this issue, I find their lack of support offensive. The support agents were all exceptionally nice and compeltely honest, so no fault of their own for sure.

 

I started poking around at my modem to look at the signal quality, errors, etc. I found a common theme within the forum for the SB8200 in that there was an update from Comcast to enable the gigabit speed that was being rejected. When I checked the error logs on my modem, I found the same error.

 

Here is the event log from the Arris.

 

Date TimeEvent IDEvent LevelDescription
2/2/2021 18:0324366940615"Dynamic Range Window violation"
2/2/2021 18:03820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 18:0324366940615"Dynamic Range Window violation"
2/2/2021 18:03820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 18:0324366940615"Dynamic Range Window violation"
2/2/2021 18:03820011005"RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 18:03730504005"REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 18:02670616006"DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1.;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 18:02680011023"Config File Rejected due to Invalid or Unexpected TLV 11 encoding;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 18:02730402003"TLV-11 - Illegal Set operation failed;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:0024366940666"Honoring MDD; IP provisioning mode = IPv6"
1/1/1970 0:00840001003"SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 12:35680011023"Config File Rejected due to Invalid or Unexpected TLV 11 encoding;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 12:35730402003"TLV-11 - Illegal Set operation failed;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:00820002003"No Ranging Response received - T3 time-out;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:00840001003"SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
2/2/2021 12:3124366940443"Resetting the cable modem due to docsDevResetNow"
1/13/2021 14:32820005003"Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/10/2021 23:16820005003"Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/5/2021 17:39820005003"Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:00820002003"No Ranging Response received - T3 time-out;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:00840001003"SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
12/23/2020 16:0024366940443"Resetting the cable modem due to docsDevResetNow"
1/1/1970 0:01820002003"No Ranging Response received - T3 time-out;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=80:e0:1d:02:6b:24;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:01840001003"SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1/1/1970 0:00840001003"SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=2c:95:69:fc:62:59;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"


The config file failure is most likely causing the gigabit speeds to not be reached, or so I thought. I went out and purchased a Motorola MB8600 modem to repalce the Arris and see if I could have any better luck.

 

The answer was no, after activating the modem and waiting 24hrs, I am receiving the same 250MB/s with the Motorola as I did with the Arris. Looking at the signal qualities the values look OK, but not great. Here are the values from the Motorola. For what it is worth, the values from the Arris were essentially the same.

 

 Downstream Bonded Channels    
   ChannelLock StatusModulationChannel IDFreq. (MHz)Pwr (dBmV)SNR (dB)CorrectedUncorrected
   1LockedQAM2564165112.841.22745115107
   2LockedQAM2561347710.840.94254637925
   3LockedQAM2561448310.740.94180436584
   4LockedQAM2561548910.740.94121735303
   5LockedQAM2561649510.540.84133433857
   6LockedQAM2561750710.440.53987032053
   7LockedQAM2561851310.440.23908331191
   8LockedQAM2561951910.240.83844629265
   9LockedQAM256205251040.73714428694
   10LockedQAM256215311040.93642927372
   11LockedQAM2562253710.140.43586126775
   12LockedQAM2562354310.240.63506726435
   13LockedQAM2562454910.3403599325953
   14LockedQAM2562555510.440.73452424690
   15LockedQAM2562656110.541.13355423737
   16LockedQAM2562756710.6413288023648
   17LockedQAM2562857310.739.83346723081
   18LockedQAM2562957910.940.13238722374
   19LockedQAM2563058510.941.13173221796
   20LockedQAM2563159111.141.13142821209
   21LockedQAM2563259711.141.23060820649
   22LockedQAM2563360311.3413005320117
   23LockedQAM2563460911.341.13003319500
   24LockedQAM2563561511.641.32958218913
   25LockedQAM2563662111.741.42982618023
   26LockedQAM2563762711.841.42937417671
   27LockedQAM256386331241.32832716913
   28LockedQAM2563963912.441.42758516663
   29LockedQAM2564064512.641.22777615878
   30LockedQAM2564265713.441.32653014368
   31LockedQAM2564366313.541.32591214144
   32LockedQAM2564466913.241.32541113601
   33LockedOFDM PLC15969014.541.883050232267
         
         
   Upstream Bonded Channels    
   ChannelLock StatusChannel TypeChannel IDSymb. Rate (Ksym/sec)Freq. (MHz)Pwr (dBmV)  
   1LockedSC-QAM1512035.645  
   2LockedSC-QAM2512029.244  
   3LockedSC-QAM3512022.843.5  
   4LockedSC-QAM4512016.443.5  
   5LockedSC-QAM5128039.647  

 

The number of uncorrectable errors is the only item that really stands out to me. The Arris also had a very large number of errors on each channel. I have checked all of the connections within the house and have not found anything out of the ordinary. If anyone has any ideas, I would appreciate the assitance. 

 

Thank you.

 

 

Matt916
New Poster

Re: Another Gigabit subscriber not getting faster than 250MB/s

I have the same issue, maxing out at ~250 down / 11.5 Up. Also using a sb8200.

i also see this in my event log.

"Config File Rejected due to Invalid or Unexpected TLV 11 encoding;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"