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T3 time out - Then internet Slows to less then 1Mbps

GeorgeNorthIV
New Poster

T3 time out - Then internet Slows to less then 1Mbps

This just started last night after Comcast had a “Scheduled outage”

Internet will work for about 3-5 min then stops. I reboot the modem and it works again for 3-5 min then stops.

I have removed everything from my network and only have a computer hardwired direct to the modem now no router involved. I have a NETGEAR CM1200 DOCSIS 3.1 modem

Comcast is saying it is a NETGEAR issue Netgear is saying it is a Comcast issue

I get the following errors in the modem log files

Started Unicast Maintenance Ranging - No Response received - T3 time-out

16 consecutive T3 timeouts while trying to range on upstream channel 2

Unicast Maintenance Ranging attempted - No response - Retries exhausted

No Ranging Response received - T3 time-out

HELP me please


EG
Expert

Re: T3 time out - Then internet Slows to less then 1Mbps

Please also post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.




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GeorgeNorthIV
New Poster

Re: T3 time out - Then internet Slows to less then 1Mbps

Frequency start ValueThis field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 555000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 5 555000000 Hz 0.8 dBmV 41.7 dB 0 0
2 Locked QAM256 2 537000000 Hz 0.2 dBmV 41.5 dB 0 0
3 Locked QAM256 3 543000000 Hz 0.3 dBmV 41.7 dB 0 0
4 Locked QAM256 4 549000000 Hz -0.5 dBmV 41.5 dB 0 0
5 Locked QAM256 6 561000000 Hz 1.4 dBmV 41.8 dB 0 0
6 Locked QAM256 7 567000000 Hz 2.2 dBmV 41.9 dB 0 0
7 Locked QAM256 8 573000000 Hz 2.6 dBmV 42 dB 0 0
8 Locked QAM256 9 579000000 Hz 1.6 dBmV 41.9 dB 0 0
9 Locked QAM256 10 585000000 Hz 0.7 dBmV 41.6 dB 0 0
10 Locked QAM256 11 591000000 Hz 1.2 dBmV 41.7 dB 0 0
11 Locked QAM256 12 597000000 Hz 0.9 dBmV 41.6 dB 0 0
12 Locked QAM256 13 603000000 Hz 1.9 dBmV 41.9 dB 0 0
13 Locked QAM256 14 609000000 Hz 1 dBmV 41.7 dB 0 0
14 Locked QAM256 15 615000000 Hz -0.6 dBmV 41 dB 0 0
15 Locked QAM256 16 621000000 Hz -2.5 dBmV 40.5 dB 0 0
16 Locked QAM256 17 627000000 Hz -4.3 dBmV 39.6 dB 0 0
17 Locked QAM256 18 633000000 Hz -3.3 dBmV 40.3 dB 0 0
18 Locked QAM256 19 639000000 Hz -3.1 dBmV 40.3 dB 0 0
19 Locked QAM256 20 645000000 Hz -1 dBmV 41.2 dB 0 0
20 Locked QAM256 21 651000000 Hz -0.6 dBmV 41.2 dB 0 0
21 Locked QAM256 22 657000000 Hz -1.6 dBmV 40.8 dB 0 0
22 Locked QAM256 23 663000000 Hz -1.3 dBmV 41 dB 0 0
23 Locked QAM256 24 669000000 Hz -0.9 dBmV 41.1 dB 0 0
24 Locked QAM256 25 675000000 Hz 0.9 dBmV 41 dB 0 0
25 Locked QAM256 26 681000000 Hz 0.4 dBmV 41.4 dB 0 0
26 Locked QAM256 27 687000000 Hz 0.2 dBmV 41.3 dB 0 0
27 Locked QAM256 28 693000000 Hz -1.2 dBmV 41 dB 0 0
28 Locked QAM256 29 699000000 Hz 0.2 dBmV 41.3 dB 0 0
29 Locked QAM256 30 705000000 Hz 1.9 dBmV 41.5 dB 0 0
30 Locked QAM256 31 711000000 Hz 2.1 dBmV 41.6 dB 0 0
31 Locked QAM256 32 717000000 Hz 2.2 dBmV 41.6 dB 0 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35600000 Hz 48.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 48.5 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 49 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 49.5 dBmV
5 Locked ATDMA 5 1280 Ksym/sec 39600000 Hz 52.8 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

Downstream OFDM Channels
Channel Lock
Status Modulation /
Profile ID Channel
ID Frequency Power SNR /
MER Active Subcarrier
Number Range Unerrored
Codewords Correctable
Codewords Uncorrectable
Codewords
1 Locked 0 ,1 ,2 ,3 41 762000000 Hz 0.6 dBmV 40.5 dB 1108 ~ 2987 1214552 1120072 0
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0

Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV
GeorgeNorthIV
New Poster

Re: T3 time out - Then internet Slows to less then 1Mbps

Sorry that’s hard to read
EG
Expert

Re: T3 time out - Then internet Slows to less then 1Mbps

The upstream power is too high / out of spec on channel 4 and it may be intermittently fluctuating even higher to out of spec levels on the other channels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

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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I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
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GeorgeNorthIV
New Poster

Re: T3 time out - Then internet Slows to less then 1Mbps

Thank you

I have a single line that comes in from the outside and splits only once with one going direct to the modem.

This has been working perfectly for 3 months and then this.

I will request a tech
EG
Expert

Re: T3 time out - Then internet Slows to less then 1Mbps

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 to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.
Good luck with it !



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GeorgeNorthIV
New Poster

Re: T3 time out - Then internet Slows to less then 1Mbps

Thank you

Do you mean channel 4 Or 5 in the upstream because 5 is higher then 4

I have a single line that comes in from the outside and splits only once with one going direct to the modem.

This has been working perfectly for 3 months and then this.

I will request a tech
EG
Expert

Re: T3 time out - Then internet Slows to less then 1Mbps

Yes I meant 5, but no matter.



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GeorgeNorthIV
New Poster

Re: T3 time out - Then internet Slows to less then 1Mbps


Can someone help explain what these numbers mean or their impact on my speed.
Right now my speed is very slow my Upstream power is between 48-49 on 5 channels

But I am getting large correctable codewords

Unerrored Codewords 98761045
Correctable Codewords 82799888



Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 5 555000000 Hz 1.9 dBmV 41.6 dB 0 0
2 Locked QAM256 1 531000000 Hz 1.4 dBmV 41.5 dB 0 0
3 Locked QAM256 2 537000000 Hz 1.1 dBmV 41.3 dB 0 0
4 Locked QAM256 3 543000000 Hz 1.2 dBmV 41.5 dB 0 0
5 Locked QAM256 4 549000000 Hz 0.6 dBmV 41.3 dB 0 0
6 Locked QAM256 6 561000000 Hz 2.6 dBmV 41.7 dB 0 0
7 Locked QAM256 7 567000000 Hz 3.5 dBmV 41.9 dB 0 0
8 Locked QAM256 8 573000000 Hz 3.8 dBmV 42 dB 0 0
9 Locked QAM256 9 579000000 Hz 2.8 dBmV 41.9 dB 0 0
10 Locked QAM256 10 585000000 Hz 2 dBmV 41.6 dB 0 0
11 Locked QAM256 11 591000000 Hz 2.5 dBmV 41.7 dB 0 0
12 Locked QAM256 12 597000000 Hz 2.2 dBmV 41.6 dB 0 0
13 Locked QAM256 13 603000000 Hz 3.3 dBmV 41.9 dB 0 0
14 Locked QAM256 14 609000000 Hz 2.3 dBmV 41.7 dB 0 0
15 Locked QAM256 15 615000000 Hz 0.6 dBmV 41 dB 0 0
16 Locked QAM256 16 621000000 Hz -1.3 dBmV 40.5 dB 0 0
17 Locked QAM256 17 627000000 Hz -3.1 dBmV 39.6 dB 0 0
18 Locked QAM256 18 633000000 Hz -2 dBmV 40.2 dB 0 0
19 Locked QAM256 19 639000000 Hz -1.7 dBmV 40.3 dB 0 0
20 Locked QAM256 33 477000000 Hz 3.4 dBmV 42.1 dB 0 0
21 Locked QAM256 34 507000000 Hz 1.6 dBmV 41.5 dB 0 0
22 Locked QAM256 35 513000000 Hz 2.3 dBmV 41.8 dB 0 0
23 Locked QAM256 36 519000000 Hz 1.1 dBmV 41.5 dB 0 0
24 Locked QAM256 37 525000000 Hz 1.7 dBmV 41.6 dB 0 0
25 Locked QAM256 38 483000000 Hz 3.2 dBmV 42.1 dB 0 0
26 Locked QAM256 39 489000000 Hz 2 dBmV 41.9 dB 0 0
27 Locked QAM256 40 495000000 Hz 1.4 dBmV 41.5 dB 0 0
28 Locked QAM256 42 453000000 Hz 4.5 dBmV 42.5 dB 0 0
29 Locked QAM256 43 459000000 Hz 4.8 dBmV 42.6 dB 0 0
30 Locked QAM256 44 465000000 Hz 4.7 dBmV 42.5 dB 0 0
31 Locked QAM256 45 471000000 Hz 4.1 dBmV 42.4 dB 0 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35600000 Hz 48 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29200000 Hz 48.3 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 22800000 Hz 48.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16400000 Hz 49 dBmV
5 Locked ATDMA 5 1280 Ksym/sec 39600000 Hz 48 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

Downstream OFDM Channels
Channel Lock
Status Modulation /
Profile ID Channel
ID Frequency Power SNR /
MER Active Subcarrier
Number Range Unerrored
Codewords Correctable
Codewords Uncorrectable
Codewords
1 Locked 0 ,1 ,2 ,3 41 762000000 Hz 2.3 dBmV 40.0 dB 1108 ~ 2987 98761045 82799888 0
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0

Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV

Extended Upstream Transmit Power
Enable Extended Upstream Transmit Power

Current System Time:Sat Aug 22 05:27:57 2020
System Up Time:07:52:00
EG
Expert

Re: T3 time out - Then internet Slows to less then 1Mbps

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, latency problems, and the un-bonding of channels.

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.



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!