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Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

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Frequent Visitor

Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

My home internet started to experience slowness when on videoconference or uploading pic/files about a week ago.  The download speed is normal though. An agent from Xfinity came to my house and checked the signal. He ruled out the problems from cables, and said the upstream power is too low (< 45dBmV), and suggested me to upgrade my modem (Arris sb6183). I then got the new one (SB8200) and still got the same low upload speed issue. So I don't think the problem is the modem. I have spoken to at least 3 specialists and all of them have no idea what's going on. The only useful info I heard is all said they receive no or weak signals from my apartment. 

 

Here are some upstream info.

Upstream Bonded Channels

ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream30300000 Hz6400000 Hz43.0 dBmV
21LockedSC-QAM Upstream17300000 Hz6400000 Hz43.0 dBmV
32LockedSC-QAM Upstream23700000 Hz6400000 Hz43.0 dBmV
44LockedSC-QAM Upstream36700000 Hz6400000 Hz43.0 dBmV
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Diamond Problem Solver

Re: Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

There’s a difference between upstream power signal levels, which you posted, and upload speeds which you didn’t post. Your levels posted are in spec. You didn’t post what your actual speeds are and what you’re expecting paying for. Did you do a speed test? Your title thread mentioned it and logs but never posted, or the downstream levels. Are you checking from your modem or from your router?

I am a Retired Official Comcast Employee
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Frequent Visitor

Re: Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

 

 

sumash_0-1603058830787.png

 

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Frequent Visitor

Re: Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

Sorry, here is more info

plan: 300/10 Mbps

download speed: 263 mbps,  upload: 0.4 mbps, latency: 63 ms, and protocal: Ipv4

 

Downstream Bonded Channels
Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
20LockedQAM256525000000 Hz-1.5 dBmV38.6 dB508211172
17LockedQAM256507000000 Hz-0.8 dBmV38.4 dB453612298
18LockedQAM256513000000 Hz-1.0 dBmV38.8 dB465011319
19LockedQAM256519000000 Hz-1.9 dBmV37.9 dB462510744
21LockedQAM256531000000 Hz-2.5 dBmV38.4 dB529511430
22LockedQAM256537000000 Hz-0.8 dBmV38.7 dB595811796
23LockedQAM256543000000 Hz-2.5 dBmV37.9 dB642611970
24LockedQAM256549000000 Hz-0.5 dBmV39.1 dB629711767
25LockedQAM256555000000 Hz-1.6 dBmV39.2 dB753011812
26LockedQAM256561000000 Hz-0.7 dBmV38.5 dB855011577
27LockedQAM256567000000 Hz-0.9 dBmV38.2 dB932011499
28LockedQAM256573000000 Hz-1.0 dBmV38.9 dB995711179
29LockedQAM256579000000 Hz-1.3 dBmV39.0 dB1047711136
30LockedQAM256585000000 Hz-1.3 dBmV38.4 dB1124310683
31LockedQAM256591000000 Hz-2.3 dBmV38.6 dB1158311481
32LockedQAM256597000000 Hz-1.9 dBmV38.7 dB1162612384
33LockedQAM256603000000 Hz-3.6 dBmV38.0 dB1141813503
34LockedQAM256609000000 Hz-2.7 dBmV38.5 dB1144013802
35LockedQAM256615000000 Hz-4.4 dBmV37.9 dB1129514521
36LockedQAM256621000000 Hz-3.2 dBmV38.2 dB1098115853
37LockedQAM256627000000 Hz-4.4 dBmV37.6 dB1004317998
38LockedQAM256633000000 Hz-4.4 dBmV37.7 dB972119223
39LockedQAM256639000000 Hz-5.4 dBmV37.5 dB935820593
40LockedQAM256645000000 Hz-6.0 dBmV37.4 dB893419936
41LockedQAM256651000000 Hz-5.3 dBmV37.8 dB863718466
42LockedQAM256657000000 Hz-5.4 dBmV37.5 dB857617609
43LockedQAM256663000000 Hz-4.4 dBmV37.8 dB857918762
44LockedQAM256669000000 Hz-5.7 dBmV37.3 dB29259644
45LockedQAM256675000000 Hz-5.4 dBmV36.6 dB807420311
46LockedQAM256681000000 Hz-7.0 dBmV36.8 dB790219928
47LockedQAM256687000000 Hz-7.3 dBmV36.7 dB8172649
48LockedOther850000000 Hz-4.2 dBmV35.8 dB15587507388384


 

 
Upstream Bonded Channels
ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream30300000 Hz6400000 Hz43.0 dBmV
21LockedSC-QAM Upstream17300000 Hz6400000 Hz43.0 dBmV
32LockedSC-QAM Upstream23700000 Hz6400000 Hz43.0 dBmV
44LockedSC-QAM Upstream36700000 Hz6400000 Hz43.0 dBmV

 

 

10/18/2020 14:09820005003"Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xxx;CM-QOS=1.1;CM-VER=3.1;"
10/18/2020 14:02740101006"CM-STATUS message sent. Event Type Code: 24; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;CM-MAC=xxx;CM-QOS=1.1;CM-VER=3.1;"
10/18/2020 14:02740101006"CM-STATUS message sent. Event Type Code: 16; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=xxx;CM-QOS=1.1;CM-VER=3.1;"
10/18/2020 14:00820005003"Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xxx;CM-QOS=1.1;CM-VER=3.1;"
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New Poster

Re: Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

I was having the extact same problem with tons of uncorrectables on all of my channels. Comcast replaced the line coming into my house and now I only have errors on channel 48. This past week, it has been really bad. The internet is so intermittent that it's borderline unuseable. I am using the SB8200. I contact comcast and they say that it's a modem problem. I contact Arris and they say that it's a comcast problem.

 

Startup Procedure
ProcedureStatusComment
Acquire Downstream Channel525000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
Configuration FileOK 
SecurityEnabledBPI+
DOCSIS Network Access EnabledAllowed 

 

 
Downstream Bonded Channels
Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
20LockedQAM256525000000 Hz7.0 dBmV41.2 dB00
17LockedQAM256507000000 Hz6.7 dBmV41.1 dB00
18LockedQAM256513000000 Hz6.4 dBmV41.0 dB00
19LockedQAM256519000000 Hz6.4 dBmV41.0 dB00
21LockedQAM256531000000 Hz7.1 dBmV41.2 dB00
22LockedQAM256537000000 Hz7.0 dBmV41.3 dB00
23LockedQAM256543000000 Hz7.2 dBmV41.2 dB00
24LockedQAM256549000000 Hz7.8 dBmV41.4 dB00
25LockedQAM256555000000 Hz7.5 dBmV41.3 dB00
26LockedQAM256561000000 Hz7.6 dBmV41.3 dB00
27LockedQAM256567000000 Hz7.9 dBmV41.3 dB00
28LockedQAM256573000000 Hz7.9 dBmV41.4 dB00
29LockedQAM256579000000 Hz7.7 dBmV41.2 dB00
30LockedQAM256585000000 Hz8.0 dBmV41.2 dB00
31LockedQAM256591000000 Hz8.4 dBmV41.5 dB00
32LockedQAM256597000000 Hz8.3 dBmV41.3 dB00
33LockedQAM256603000000 Hz8.3 dBmV41.3 dB00
34LockedQAM256609000000 Hz8.5 dBmV41.4 dB00
35LockedQAM256615000000 Hz8.6 dBmV41.3 dB00
36LockedQAM256621000000 Hz8.5 dBmV41.4 dB00
37LockedQAM256627000000 Hz8.7 dBmV41.3 dB00
38LockedQAM256633000000 Hz8.9 dBmV41.5 dB00
39LockedQAM256639000000 Hz8.7 dBmV41.4 dB00
40LockedQAM256645000000 Hz8.8 dBmV41.5 dB00
41LockedQAM256651000000 Hz8.9 dBmV41.5 dB00
42LockedQAM256657000000 Hz9.1 dBmV41.7 dB00
43LockedQAM256663000000 Hz8.9 dBmV41.5 dB00
44LockedQAM256669000000 Hz8.8 dBmV41.6 dB150
45LockedQAM256675000000 Hz9.2 dBmV41.5 dB00
46LockedQAM256681000000 Hz8.6 dBmV41.5 dB00
47LockedQAM256687000000 Hz8.9 dBmV41.7 dB00
48LockedOther850000000 Hz7.2 dBmV39.5 dB6219005720


 

 
Upstream Bonded Channels
ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream30300000 Hz6400000 Hz44.0 dBmV
21LockedSC-QAM Upstream17300000 Hz6400000 Hz45.0 dBmV
35LockedSC-QAM Upstream41200000 Hz1600000 Hz43.0 dBmV
42LockedSC-QAM Upstream23700000 Hz6400000 Hz45.0 dBmV
54LockedSC-QAM Upstream36700000 Hz6400000 Hz44.0 dBmV
Highlighted
Frequent Visitor

Re: Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

Thanks for the information. That's very useful. Do you still have the same problem after they replaced the line to your house?  I have seen other people's log also shows channel 48 having lots of errors (It seems to be normal though I don't know why)

 

The following was what I experienced as well. 


@Snic8 wrote:

I contact comcast and they say that it's a modem problem. I contact Arris and they say that it's a comcast problem.

Another tech came yesterday and did a full diagnosis on all possible causes, and concluded it's Xfinity's problem (in the box outside my apartment).  They are sending someone to fix it. 

 

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Frequent Visitor

Re: Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.

The last agent said they will fix it in 3 days.  Still, no response from Xfinity and the internet cannot be worse, with a few outages in the past few days.  really disappointed.