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Slow uploads - Unicast Maintenance Ranging T3 Time Outs on upstream channel
I'm frequently losing internet connection throughout the day, and when there is connection, upload speed can be below 1Mbps when I should get 5Mbps. Also, my download speed should be 175Mbps, but I get often get only 25Mbps or less. At night, I often get to 200Mbps down and almost 6Mbps up.
I found an article on timeouts.
https://pickmymodem.com/cable-modem-t3-and-t4-timeouts-error-messages-and-how-to-fix-them/
I've tried the following:
1. check for loose cables.
2. remove extra splitters
3. ordering a power amplifier - will try to see if this helps but it won't come for a while.
What else can I do? I've called Comcast many times and all the modem and router reboots didn't solve the problem. I also bought a new router. One agent said they'll send someone out, but no one called to schedule a visit. I called back several times and the agent said that Comcast will only send people out if my internet doesn't work at all.
Thank you for any suggestion.
Here's the information on my Motorola MB7621 DOCSIS 3.0 Modem
Startup Sequence Startup Step Status Comment Acquire Downstream Channel 603000000 Hz Locked Upstream Connection. OK Operational Boot State OK Operational Configuration File OK d11_m_mb7621_performancepro_c01.cm Security Enabled BPI+ ------------------------------ Connection Status System Up Time 0 days 01h:36m:02s Network Access Allowed ------------------------------ Downstream Bonded Channels Channel Lock Status Channel Freq. Pwr SNR Corrected Uncorrected 1 Locked QAM256 32 603.0 2.9 39.6 2 0 2 Locked QAM256 24 555.0 2.7 40.6 0 0 3 Locked QAM256 25 561.0 2.6 40.5 0 0 4 Locked QAM256 26 567.0 2.6 40.3 0 0 5 Locked QAM256 27 573.0 3.2 39.9 0 0 6 Locked QAM256 28 579.0 2.1 40.1 2 0 7 Locked QAM256 29 585.0 2.8 40.0 0 0 8 Locked QAM256 30 591.0 2.6 40.2 1 0 9 Locked QAM256 31 597.0 2.8 40.5 2 0 10 Locked QAM256 33 609.0 2.4 40.0 4 0 11 Locked QAM256 34 615.0 3.1 40.6 0 0 12 Locked QAM256 35 621.0 2.7 40.6 2 0 13 Locked QAM256 36 627.0 3.0 40.7 3 0 14 Locked QAM256 37 633.0 2.9 40.6 5 0 15 Locked QAM256 38 639.0 3.4 40.6 1 0 16 Locked QAM256 39 645.0 3.5 41.0 0 0 17 Locked QAM256 40 651.0 3.0 42.1 2 0 18 Locked QAM256 41 657.0 3.3 42.0 2 0 19 Locked QAM256 42 663.0 2.7 41.9 1 0 20 Locked QAM256 43 669.0 2.9 42.1 0 0 21 Locked QAM256 44 675.0 2.4 41.8 5 0 22 Locked QAM256 45 681.0 2.4 41.7 2 0 23 Locked QAM256 46 687.0 2.3 41.8 6 0 24 Locked QAM256 47 693.0 2.1 42.0 0 0 Total 40 0 Upstream Bonded Channels Channel Lock ChanType ChanlID Symb.Rate Freq. Pwr (dBmV) 1 Locked ATDMA 8 5120 36.7 49.3 2 Locked ATDMA 5 5120 17.3 49.2 3 Locked ATDMA 6 5120 23.7 49.2 4 Locked ATDMA 7 5120 30.3 49.2 5 Not Locked Unknown 0 0 0 0.0 6 Not Locked Unknown 0 0 0 0.0 7 Not Locked Unknown 0 0 0 0.0 8 Not Locked Unknown 0 0 0 0.0
Event Log
Log Time Priority Description Fri Apr 24 18:58:35 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 18:58:35 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 18:58:35 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 18:58:35 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:21 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:21 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:21 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:45 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:45 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:45 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:45 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:45 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:05:45 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:34 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:34 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:34 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:58 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:58 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:58 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:58 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:58 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:12:58 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:19:46 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:19:46 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:19:46 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0; Fri Apr 24 19:20:10 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:60:58:c4;CMTS-MAC=00:01:5c:63:42:66;CM-QOS=1.1;CM-VER=3.0;
Accepted Solution
EG
Expert
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111.4K Messages
5 years ago
The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there 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 types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
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.
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tom_wa052511
Frequent Visitor
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7 Messages
5 years ago
Thank you, EG, for your review and feedback.
I will check the cables again tomorrow to ensure that I don't have other splitters.
Also, would an amplifier such as these be helpful?
https://www.amazon.com/gp/product/B0792MVBB3/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B077BCHVWZ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
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EG
Expert
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111.4K Messages
5 years ago
Amps should only be used as a last resort. They are a *band-aid* type of approach. "Garbage in = even more garbage out". The connection should be fixed in the proper way.
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tom_wa052511
Frequent Visitor
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7 Messages
5 years ago
FYI - Followup info.
After almost 2 months, Comcast sent a tech to my house. He checked the cables both inside and outside the house. He found some issues and replaced a few old connectors with new ones, but the speed did not improve. He said that there's an internet capacity issue in my area because of too many people on the internet, and Comcast is working to fix that but the work is still on going.
Also, the upstream power shown on the Motorola Cable Modem was a bit high, and putting in the Arris Amplifier did help to reduce the upstream power level. The tech told me to keep the Amplifier for now. He said to get upstream power reduced, Comcast needs to send someone out to fix at the tap on the pole outside my house.
I also tried the CommScope amplifier, but it didn't reduce the upstream power at all like the Arris Amplifier does.
I still have the T3 Time Outs errors on the Motorola modem.
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dosers
Regular Visitor
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4 Messages
5 years ago
Hi,
started about 5 days ago, seems to be similar to others; I have between 2-6 outages daily now (lasting 1-3 minutes each), all with that message. Power levels seem to be fine, all cable connections are tight. Just moved in (new construction) 4 months ago, and all was fine until now...?
Where do I 'go' for help? Modem is CM1200 (Have GIg speed down, 50Mb up)
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Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=28:80:88:b3:7a:b0;CMTS-MAC=00:01:5c:a9:34:61;CM-QOS=1.1;CM-VER=3.1;
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