CaptainHammer's profile

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6 Messages

Fri, Nov 27, 2020 3:00 PM

Cable Modem: Started Unicast Maintenance Ranging - No Response received - T3 time-out

I've had Xfinity internet at my house for about 9 years, but within the last few months the connection has been unstable. Speed will grind to a halt, and I'll find that I need to reset my cable modem (Netgear CM1150V) or wireless router (Eero Pro) daily to restore normal service. I've checked the cable modem logs, and see this message frequently:

 

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

 

Am I having upstream SnR issues? Happy to post any logs that are needed. Thank you in advance!

Responses

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6 Messages

7 m ago

Here's some additional information that might be of use:

 

Startup procedure

ProcedureStatusComment
Acquire Downstream Channel525000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnabledBPI+
IP Provisioning ModeHonor MDDhonorMdd(4)

 

Downstream Bonded Channels

ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25620525000000 Hz-2.5 dBmV40.6 dB124185
2LockedQAM25617507000000 Hz-1.5 dBmV40.9 dB64134
3LockedQAM25618513000000 Hz-1.6 dBmV40.9 dB87138
4LockedQAM25619519000000 Hz-2 dBmV40.9 dB67126
5LockedQAM25621531000000 Hz-2.6 dBmV40.5 dB196353
6LockedQAM25622537000000 Hz-2.9 dBmV40.4 dB284460
7LockedQAM25623543000000 Hz-3.3 dBmV40.2 dB292566
8LockedQAM25624549000000 Hz-3.8 dBmV40.1 dB296700
9LockedQAM25625555000000 Hz-3.9 dBmV40 dB339684
10LockedQAM25626561000000 Hz-4 dBmV39.9 dB373782
11LockedQAM25627567000000 Hz-4.4 dBmV39.7 dB324725
12LockedQAM25628573000000 Hz-4.8 dBmV39.5 dB327585
13LockedQAM25629579000000 Hz-4.8 dBmV39.4 dB295449
14LockedQAM25630585000000 Hz-4.8 dBmV39.4 dB165203
15LockedQAM25631591000000 Hz-5 dBmV39.3 dB83153
16LockedQAM25632597000000 Hz-5 dBmV39.3 dB6859
17LockedQAM25633603000000 Hz-5.1 dBmV39.1 dB3539
18LockedQAM25634609000000 Hz-5.2 dBmV39 dB568
19LockedQAM25635615000000 Hz-5.4 dBmV38.9 dB4614
20LockedQAM25636621000000 Hz-5.3 dBmV38.9 dB3540
21LockedQAM25637627000000 Hz-5.4 dBmV38.8 dB8390
22LockedQAM25638633000000 Hz-5.6 dBmV38.7 dB57130
23LockedQAM25639639000000 Hz-6 dBmV38.5 dB121172
24LockedQAM25640645000000 Hz-6 dBmV38.5 dB144246
25LockedQAM25641651000000 Hz-6.3 dBmV38.3 dB219332
26LockedQAM25642657000000 Hz-6.6 dBmV38.2 dB165420
27LockedQAM25643663000000 Hz-6.7 dBmV38.1 dB336413
28LockedQAM25644669000000 Hz-6.5 dBmV38.3 dB246327
29LockedQAM25645675000000 Hz-6.6 dBmV37.3 dB136225
30LockedQAM25646681000000 Hz-7.1 dBmV38 dB97159
31LockedQAM25647687000000 Hz-7 dBmV38 dB49103
32Not LockedUnknown00 Hz0.0 dBmV0.0 dB00

 

Upstream Bonded Channels

ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA135120 Ksym/sec19300000 Hz53 dBmV
2LockedATDMA145120 Ksym/sec25700000 Hz53.3 dBmV
3LockedATDMA155120 Ksym/sec32300000 Hz53 dBmV
4LockedATDMA165120 Ksym/sec38700000 Hz54 dBmV
5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
8Not LockedUnknown00 Ksym/sec0 Hz

0.0 dBmV

 

 

Downstream OFDM Channels

ChannelLock
Status
Modulation /
Profile ID
Channel
ID
FrequencyPowerSNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0 ,1 ,2 ,348850000000 Hz-9.6 dBmV35.3 dB1108 ~ 29872513647082471580338376
2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000
BruceW

Gold Problem Solver

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22.4K Messages

7 m ago

The upstream power levels are too high. This suggests a problem between your equipment and Comcast's network. Network connection problems are often due to poor coax connections or damaged coax cable, usually in or near your home.

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. If they can't fix the problem remotely (unlikely), insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

 

Frequent Visitor

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6 Messages

7 m ago

Hi @BruceW,

 

Thanks for the reply. Here's the steps I've taken since yesterday:

 

  1. Replaced my cable modem with an older model I had in storage (Netgear CM500V)
  2. Removed a splitter between the wall and the cable modem
  3. Replaced the coaxial cable between the wall and the cable modem.

 

The good news is that things seem more stable. Yesterday I ran a speedtest and had jitter around 200ms and packet loss around 30%! Today's jitter is 3.5ms with 0 packet loss.

 

Now, as far as the upstream power levels - do these still seem too high?

 

Upstream Bonded Channels

ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA135120 Ksym/sec19300000 Hz47.8 dBmV
2LockedATDMA145120 Ksym/sec25700000 Hz48.3 dBmV
3LockedATDMA155120 Ksym/sec32300000 Hz48.8 dBmV
4LockedATDMA165120 Ksym/sec38700000 Hz50.5 dBmV

 

If so, then that means it's somewhere between the wall and the street, correct?

 

Thanks again for your help!

BruceW

Gold Problem Solver

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22.4K Messages

7 m ago


@CaptainHammer wrote: ... do these still seem too high? ... If so, then that means it's somewhere between the wall and the street, correct?

Upstream power levels are better, but uncomfortably close to the max. I like to see them between 40 and 45, but these may be OK if they are stable.

Since you've replaced the modem and the cabling to the wall jack then yes, if there is still a problem it should be in the wall jack or beyond.

Bottom line: is it working as it should? If so, good! If not, more needs to be done.

Good luck!

 

Frequent Visitor

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6 Messages

6 m ago

Hey @BruceW,

 

It's been a few days and things seem to be more stable with the older modem and different cables. However, I just had to power cycle the modem as the internet all of a sudden stopped working. This wasn't slow speeds - it was no speeds, no connection.

 

Could it be related to the previous problems, or just a small hiccup? I've got another modem arriving in a few days and will try that out. I'm just starting to get to my wits' end - with me doing remote work and my son doing online classes, we rely on uptime pretty heavily. Think I should call Xfinity and get a technician out to check the lines?

BruceW

Gold Problem Solver

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22.4K Messages

6 m ago


@CaptainHammer wrote: ... I just had to power cycle the modem ... Could it be related to the previous problems ...

Can you post the current power level and SNR readings? If they're not in spec and you can't correct them, then yes, have Comcast out to take a look.

 

Frequent Visitor

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6 Messages

6 m ago

Here's the current power level and SNR readings. Had an uptime of about 10 hours:

 

Downstream Bonded Channels

ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25632597000000 Hz-2 dBmV37.2 dB80
2LockedQAM25633603000000 Hz-2 dBmV36.9 dB130
3LockedQAM25634609000000 Hz-2.1 dBmV37 dB70
4LockedQAM25635615000000 Hz-2.2 dBmV37.1 dB110
5LockedQAM25636621000000 Hz-2.2 dBmV37 dB60
6LockedQAM25637627000000 Hz-2.2 dBmV36.9 dB140
7LockedQAM25638633000000 Hz-2.3 dBmV36.8 dB100
8LockedQAM25639639000000 Hz-2.6 dBmV36.4 dB90
9LockedQAM25640645000000 Hz-2.5 dBmV36.6 dB50
10LockedQAM25641651000000 Hz-2.8 dBmV36.4 dB150
11LockedQAM25642657000000 Hz-2.9 dBmV36.3 dB190
12LockedQAM25643663000000 Hz-3 dBmV36.1 dB250
13LockedQAM25644669000000 Hz-2.7 dBmV36.3 dB140
14LockedQAM25645675000000 Hz-2.7 dBmV36 dB170
15LockedQAM25646681000000 Hz-3 dBmV36 dB270
16LockedQAM25647687000000 Hz-3.2 dBmV36 dB250

 

Upstream Bonded Channels

ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA155120 Ksym/sec32300000 Hz49 dBmV
2LockedATDMA135120 Ksym/sec19300000 Hz47.8 dBmV
3LockedATDMA145120 Ksym/sec25700000 Hz48.5 dBmV
4LockedATDMA165120 Ksym/sec38700000 Hz50.5 dBmV
BruceW

Gold Problem Solver

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22.4K Messages

6 m ago


@CaptainHammer wrote: Here's the current power level and SNR readings. ...

Upstream power levels are still uncomfortably close to the max of 51. Again, if your Internet service is not working as it should and you can't fix it, have a Comcast tech come out.

 

Frequent Visitor

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6 Messages

6 m ago

I'm now losing the lock status on some of the upstream bonded channels with the associated power levels dropping to 0.0 dBmV. Technician is scheduled for tomorrow.

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