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 Time | Event ID | Event Level | Description |
| 2/2/2021 18:03 | 2436694061 | 5 | "Dynamic Range Window violation" |
| 2/2/2021 18:03 | 82001100 | 5 | "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 18:03 | 2436694061 | 5 | "Dynamic Range Window violation" |
| 2/2/2021 18:03 | 82001100 | 5 | "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 18:03 | 2436694061 | 5 | "Dynamic Range Window violation" |
| 2/2/2021 18:03 | 82001100 | 5 | "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 18:03 | 73050400 | 5 | "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 18:02 | 67061600 | 6 | "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 18:02 | 68001102 | 3 | "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 18:02 | 73040200 | 3 | "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 0:00 | 2436694066 | 6 | "Honoring MDD; IP provisioning mode = IPv6" |
| 1/1/1970 0:00 | 84000100 | 3 | "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 12:35 | 68001102 | 3 | "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 12:35 | 73040200 | 3 | "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 0:00 | 82000200 | 3 | "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 0:00 | 84000100 | 3 | "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 12:31 | 2436694044 | 3 | "Resetting the cable modem due to docsDevResetNow" |
| 1/13/2021 14:32 | 82000500 | 3 | "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 23:16 | 82000500 | 3 | "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 17:39 | 82000500 | 3 | "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 0:00 | 82000200 | 3 | "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 0:00 | 84000100 | 3 | "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 16:00 | 2436694044 | 3 | "Resetting the cable modem due to docsDevResetNow" |
| 1/1/1970 0:01 | 82000200 | 3 | "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 0:01 | 84000100 | 3 | "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 0:00 | 84000100 | 3 | "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 | | | | |
| Channel | Lock Status | Modulation | Channel ID | Freq. (MHz) | Pwr (dBmV) | SNR (dB) | Corrected | Uncorrected |
| 1 | Locked | QAM256 | 41 | 651 | 12.8 | 41.2 | 27451 | 15107 |
| 2 | Locked | QAM256 | 13 | 477 | 10.8 | 40.9 | 42546 | 37925 |
| 3 | Locked | QAM256 | 14 | 483 | 10.7 | 40.9 | 41804 | 36584 |
| 4 | Locked | QAM256 | 15 | 489 | 10.7 | 40.9 | 41217 | 35303 |
| 5 | Locked | QAM256 | 16 | 495 | 10.5 | 40.8 | 41334 | 33857 |
| 6 | Locked | QAM256 | 17 | 507 | 10.4 | 40.5 | 39870 | 32053 |
| 7 | Locked | QAM256 | 18 | 513 | 10.4 | 40.2 | 39083 | 31191 |
| 8 | Locked | QAM256 | 19 | 519 | 10.2 | 40.8 | 38446 | 29265 |
| 9 | Locked | QAM256 | 20 | 525 | 10 | 40.7 | 37144 | 28694 |
| 10 | Locked | QAM256 | 21 | 531 | 10 | 40.9 | 36429 | 27372 |
| 11 | Locked | QAM256 | 22 | 537 | 10.1 | 40.4 | 35861 | 26775 |
| 12 | Locked | QAM256 | 23 | 543 | 10.2 | 40.6 | 35067 | 26435 |
| 13 | Locked | QAM256 | 24 | 549 | 10.3 | 40 | 35993 | 25953 |
| 14 | Locked | QAM256 | 25 | 555 | 10.4 | 40.7 | 34524 | 24690 |
| 15 | Locked | QAM256 | 26 | 561 | 10.5 | 41.1 | 33554 | 23737 |
| 16 | Locked | QAM256 | 27 | 567 | 10.6 | 41 | 32880 | 23648 |
| 17 | Locked | QAM256 | 28 | 573 | 10.7 | 39.8 | 33467 | 23081 |
| 18 | Locked | QAM256 | 29 | 579 | 10.9 | 40.1 | 32387 | 22374 |
| 19 | Locked | QAM256 | 30 | 585 | 10.9 | 41.1 | 31732 | 21796 |
| 20 | Locked | QAM256 | 31 | 591 | 11.1 | 41.1 | 31428 | 21209 |
| 21 | Locked | QAM256 | 32 | 597 | 11.1 | 41.2 | 30608 | 20649 |
| 22 | Locked | QAM256 | 33 | 603 | 11.3 | 41 | 30053 | 20117 |
| 23 | Locked | QAM256 | 34 | 609 | 11.3 | 41.1 | 30033 | 19500 |
| 24 | Locked | QAM256 | 35 | 615 | 11.6 | 41.3 | 29582 | 18913 |
| 25 | Locked | QAM256 | 36 | 621 | 11.7 | 41.4 | 29826 | 18023 |
| 26 | Locked | QAM256 | 37 | 627 | 11.8 | 41.4 | 29374 | 17671 |
| 27 | Locked | QAM256 | 38 | 633 | 12 | 41.3 | 28327 | 16913 |
| 28 | Locked | QAM256 | 39 | 639 | 12.4 | 41.4 | 27585 | 16663 |
| 29 | Locked | QAM256 | 40 | 645 | 12.6 | 41.2 | 27776 | 15878 |
| 30 | Locked | QAM256 | 42 | 657 | 13.4 | 41.3 | 26530 | 14368 |
| 31 | Locked | QAM256 | 43 | 663 | 13.5 | 41.3 | 25912 | 14144 |
| 32 | Locked | QAM256 | 44 | 669 | 13.2 | 41.3 | 25411 | 13601 |
| 33 | Locked | OFDM PLC | 159 | 690 | 14.5 | 41.8 | 83050232 | 267 |
| | | | | | | | | |
| | | | | | | | | |
| Upstream Bonded Channels | | | | |
| Channel | Lock Status | Channel Type | Channel ID | Symb. Rate (Ksym/sec) | Freq. (MHz) | Pwr (dBmV) | | |
| 1 | Locked | SC-QAM | 1 | 5120 | 35.6 | 45 | | |
| 2 | Locked | SC-QAM | 2 | 5120 | 29.2 | 44 | | |
| 3 | Locked | SC-QAM | 3 | 5120 | 22.8 | 43.5 | | |
| 4 | Locked | SC-QAM | 4 | 5120 | 16.4 | 43.5 | | |
| 5 | Locked | SC-QAM | 5 | 1280 | 39.6 | 47 | | |
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.
