Comcast XFINITY → [Connectivity] Latency due to packet loss

I am have very strange upload speed problems.

During the day my speed tests are more likely come back with correct results. 35mb download and around 5mb upload. This isn't always the case, sometimes my upload speed will be sub 1mb. If the test even starts.

However come late afternoon continuing till the morning my upload speed is very bad to the point I can't even upload a 7mb file with out it timing out.

My download speed is never affected nor is my connectivity.

I have had techs come out many times to my house only to tell me my signal and all of my numbers are what they should be and that nothing is wrong. To make matters worse when they do come out it just so happens to be times when my internet it working the way it was supposed to. I have had Comcast ping my modem and get about a 4% packet loss when they do.

I have replaced my modem 3 different times.

I don't run a router.

I have checked all of my network card drivers. I have run test with very outdated drivers, newer ones, and the newest ones. Doesn't fix anything.

I have changed all of my cables many times.

I have checked for viruses with 3 different anti viruses (Kaspersky, AVG, and Avast). No viruses

I have checked for maleware, nothing.

I have had the same issue with an older computer so I find it very hard to believe that it is related to my network card. Could the low frequency of my Upstream be the cause.

Line Quality Test:
»/pingt ··· /2954575

Modem: Arris WBM760A
Downstream 1 -2.06 dBmV 36.84 dB
Downstream 2 -2.40 dBmV 36.39 dB
Downstream 3 - 2.87 dBmV 36.39 dB
Downstream 4 -1.30 dBmV 37.36 dB

Upstream 1 34.80 MHz 50.25 dBmV DOCSIS2.0 (ATDMA)
Upstream 2 27.90 MHz 49.25 dBmV DOCSIS1.x (TDMA)

Upstream SNR (when I called) 34db

ShaperProbe Results
Upstream: 6166 Kbps.
Downstream: 35153 Kbps.
Upstream: Measurement aborted due to high packet loss rate.
Downstream: Never actually finished...ShaperProbe crashed...

Please I really need some help getting this resolved.

Your upstream signal levels are high. For 2-channel, they are OK (limit is 54dB), but marginal.

Since it seems to occur at a consistent time, it could either be sun/heat related, or you have several users on your node who are prolific uploaders/BitTorrent that are clogging the upstream pipes.

FWIW, it could be return path noise ingress as well.

Usually RF noise on the upstream. Can be caused by ham, CB, and shortwave operators working outside FCC guidelines, people plugging a digital TV tuner's output into the cable line in their home (will affect the whole node), and various other things.

Basic rule: Report it.

When they say it's fine, report it again when it happens again, and provide hard evidence each time.

Third truck dispatch in a month should get you a supervisor who can escalate it to a line engineer and then... sadly... wait up to four months depending on what they have to track down and how infrequent it is.

post a copy of our modem's log file from a period of time when you're having problems. Let's see if there are T3/T4 timeouts in it.

No Ranging Response received - T3 time-out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

RCS Partial Service;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

Lost MDD Timeout;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

RCS Partial Service;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

MDD IP mode Override Mode=0;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.0;

That's before and after my last reset.

Got another T3 time out later in the day while I was at work.