Visitor
•
8 Messages
Recurring loss of upload bandwidth during specific time range at night
I am currently subscribed at the 1200/(35) Mbps plan and live in a taller apartment building. Since moving in last month, I have been having consistent nightly internet issues from approximately 6:00pm to 5:00am - during these night hours, upload speeds will degrade to <0.3 Mbps, low enough to effectively time out all outbound requests. Download speeds oddly are unaffected, and when a Xfinity/Fast.com/SpeedTest.net/Google speed test does execute, I see 300Mbps+ download speeds (and <0.3Mbps upload). Despite this, without upload bandwidth the internet is unusable. I have worked with the two Xfinity technicians so far in attempting to diagnose the issue but that has been unfruitful.

I have tested different modems (S33, xFi Gateway, SB8200) different computers, different Ethernet cables, different power outlets, and technicians have checked signal integrity between my building floor's tap and the coaxial cable in the apartment during regular business hours - all seemingly clean with no signs of noise or ingress. They have mentioned that power levels were high at the tap, but should level off once in my apartment. I am not sure if other residents on the same my floor's tap are experiencing similar issues at night. What is frustrating is that during the day (5:00am-6:00pm) internet speeds are nominal (1300Mbps down, although upload always only caps at 20Mbps). Only after these hours does it degrade, and technicians are unavailable outside of business hours, so they are unable to see the issue firsthand.
Is it possible that some damage has occurred to the line into my apartment, and the temperature fluctuation of day and night exacerbates the issue - during the evening my upstream power levels are about +1 to +2dBmV from what is shown below. Another suspicion I have is that an automatic power source of some sort (timed street/building lamp?) is feeding noise into my unit’s line during these hours.
I appreciate having techs sent over to inspect but I feel like their time is wasted when they do not see the issue firsthand. Any assistance or pointers are greatly appreciated. Kind of getting tired of not having internet at night :)
Edit: The technicians have also said their "network guys" don't see any issues at night.
Arris S33
I see log Event Type Codes 16, 20, 22, and 24 for channel 48, but never any T3/T4 timeouts.
Downstream Bonded Channels | |||||||
---|---|---|---|---|---|---|---|
Channel ID | Lock Status | Modulation | Frequency | Power | SNR/MER | Corrected | Uncorrectables |
20 | Locked | QAM256 | 507000000 Hz | 1 dBmV | 40 dB | 1856 | 0 |
4 | Locked | QAM256 | 405000000 Hz | 1 dBmV | 41 dB | 2399 | 0 |
5 | Locked | QAM256 | 411000000 Hz | 1 dBmV | 41 dB | 2306 | 0 |
6 | Locked | QAM256 | 417000000 Hz | 1 dBmV | 41 dB | 2230 | 0 |
7 | Locked | QAM256 | 423000000 Hz | 1 dBmV | 41 dB | 2177 | 0 |
8 | Locked | QAM256 | 429000000 Hz | 1 dBmV | 41 dB | 2185 | 0 |
9 | Locked | QAM256 | 435000000 Hz | 1 dBmV | 41 dB | 2174 | 0 |
10 | Locked | QAM256 | 441000000 Hz | 1 dBmV | 40 dB | 2131 | 0 |
11 | Locked | QAM256 | 447000000 Hz | 1 dBmV | 41 dB | 2153 | 0 |
12 | Locked | QAM256 | 453000000 Hz | 1 dBmV | 40 dB | 2138 | 0 |
13 | Locked | QAM256 | 459000000 Hz | 1 dBmV | 40 dB | 2050 | 0 |
14 | Locked | QAM256 | 465000000 Hz | 0 dBmV | 40 dB | 2083 | 0 |
15 | Locked | QAM256 | 471000000 Hz | 1 dBmV | 40 dB | 2004 | 0 |
16 | Locked | QAM256 | 477000000 Hz | 1 dBmV | 41 dB | 1973 | 0 |
17 | Locked | QAM256 | 483000000 Hz | 1 dBmV | 41 dB | 1993 | 0 |
18 | Locked | QAM256 | 489000000 Hz | 1 dBmV | 41 dB | 2017 | 0 |
19 | Locked | QAM256 | 495000000 Hz | 1 dBmV | 40 dB | 1972 | 0 |
21 | Locked | QAM256 | 513000000 Hz | 0 dBmV | 40 dB | 1829 | 0 |
22 | Locked | QAM256 | 519000000 Hz | 0 dBmV | 40 dB | 1799 | 0 |
23 | Locked | QAM256 | 525000000 Hz | 0 dBmV | 40 dB | 1769 | 0 |
24 | Locked | QAM256 | 531000000 Hz | 0 dBmV | 40 dB | 1686 | 0 |
25 | Locked | QAM256 | 537000000 Hz | 1 dBmV | 40 dB | 1683 | 0 |
26 | Locked | QAM256 | 543000000 Hz | 1 dBmV | 41 dB | 1633 | 0 |
27 | Locked | QAM256 | 549000000 Hz | 1 dBmV | 40 dB | 1619 | 0 |
28 | Locked | QAM256 | 555000000 Hz | 2 dBmV | 41 dB | 1499 | 0 |
29 | Locked | QAM256 | 561000000 Hz | 2 dBmV | 41 dB | 1546 | 0 |
30 | Locked | QAM256 | 567000000 Hz | 2 dBmV | 40 dB | 1584 | 0 |
31 | Locked | QAM256 | 573000000 Hz | 2 dBmV | 40 dB | 1513 | 0 |
32 | Locked | QAM256 | 579000000 Hz | 2 dBmV | 40 dB | 1508 | 0 |
33 | Locked | QAM256 | 585000000 Hz | 2 dBmV | 40 dB | 1385 | 0 |
34 | Locked | QAM256 | 591000000 Hz | 2 dBmV | 40 dB | 1346 | 0 |
48 | Locked | OFDM PLC | 850000000 Hz | 4 dBmV | 39 dB | 1036006730 | 0 |
Upstream Bonded Channels | ||||||
---|---|---|---|---|---|---|
Channel ID | Lock Status | US Channel Type | Frequency | Width | Power | |
1 | Locked | SC-QAM | 16400000 Hz | 6400000 | 48.5 dBmV | |
2 | Locked | SC-QAM | 22800000 Hz | 6400000 | 49.8 dBmV | |
3 | Locked | SC-QAM | 29200000 Hz | 6400000 | 50.0 dBmV | |
4 | Locked | SC-QAM | 35600000 Hz | 6400000 | 51.0 dBmV | |
5 | Locked | SC-QAM | 40400000 Hz | 3200000 | 51.8 dBmV |
xFi Gateway
Downstream
|
Channel Bonding Value | |||||||||||||||||||||||||||||||
Index |
20
|
17
|
18
|
19
|
21
|
22
|
23
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
31
|
32
|
33
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
41
|
42
|
43
|
44
|
45
|
46
|
47
|
48
|
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Lock Status |
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Frequency |
507000000
|
483000000
|
489000000
|
495000000
|
513000000
|
519000000
|
525000000
|
531000000
|
537000000
|
543000000
|
549000000
|
555000000
|
561000000
|
567000000
|
573000000
|
579000000
|
585000000
|
591000000
|
597000000
|
603000000
|
609000000
|
615000000
|
621000000
|
627000000
|
633000000
|
639000000
|
645000000
|
651000000
|
681000000
|
687000000
|
693000000
|
852800000
|
SNR |
38.983261
|
38.983261
|
40.366287
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.605377
|
40.366287
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.983261
|
38.605377
|
38.605377
|
38.983261
|
38.605377
|
38.605377
|
38.983261
|
38.605377
|
38.605377
|
38.605377
|
38.605377
|
38.605377
|
38.605377
|
NA
|
Power Level |
2.900002
|
3.099998
|
3.200001
|
3.099998
|
2.799999
|
2.700001
|
2.900002
|
3.000000
|
3.200001
|
3.400002
|
3.599998
|
3.900002
|
3.799999
|
3.799999
|
3.799999
|
3.700001
|
3.900002
|
3.900002
|
3.799999
|
3.799999
|
3.799999
|
3.799999
|
3.900002
|
4.199997
|
4.000000
|
3.799999
|
3.500000
|
3.599998
|
3.200001
|
3.599998
|
3.799999
|
NA
|
Modulation |
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
QAM256
|
OFDM
|
Upstream
|
Channel Bonding Value | |||||
Index |
1
|
2
|
3
|
4
|
5
|
|
---|---|---|---|---|---|---|
Lock Status |
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
|
Frequency |
16400000
|
40400000
|
35600000
|
29200000
|
22800000
|
|
Symbol Rate |
5120 KSym/sec
|
2560 KSym/sec
|
5120 KSym/sec
|
5120 KSym/sec
|
5120 KSym/sec
|
|
Power Level |
47.270599
|
50.760300
|
50.270599
|
49.020599
|
48.270599
|
|
Modulation |
64QAM
|
64QAM
|
64QAM
|
64QAM
|
64QAM
|
|
Channel Type |
US_TYPE_ATDMA
|
US_TYPE_ATDMA
|
US_TYPE_ATDMA
|
US_TYPE_ATDMA
|
US_TYPE_ATDMA
|
CM Error Codewords | ||||||||||||||||||||||||||||||||
Unerrored Codewords |
9259
|
9104
|
8981
|
8876
|
8766
|
8648
|
8527
|
8426
|
8311
|
8172
|
8048
|
7943
|
7828
|
7680
|
7562
|
7459
|
7347
|
7185
|
7061
|
6946
|
6825
|
6704
|
6600
|
6486
|
6362
|
6241
|
6107
|
5933
|
5811
|
5706
|
5593
|
559030611
|
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Correctable Codewords |
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
3735936685
|
Uncorrectable Codewords |
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
3735936685
|
EG
Expert
•
111.6K Messages
4 years ago
The upstream power is too high. That indicates an upsteam channel / return path line impairment of some sort (possibly noise ingress). You need to get the techs involved again. It's possible that drop amplifier with an *active return* may need to be installed on your line. Lean on them until it gets fixed properly. Good luck !
1
EG
Expert
•
111.6K Messages
4 years ago
He's wrong... We've seen it to be always to the contrary here... .No surprise here.... 51 dB is the limit. Comcast turned off the extended upstream power feature a few years ago. I really wish that the techs would get more up to date training than they do..... Don't know how they operate this way.... 35 to 45 dB is the sweet spot. I'm not an employee. I don't know how else to help you.... Sorry...
0
0