Regular Visitor
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7 Messages
Advertised Upload Speeds
Hi. I am having issues getting full upload speeds from my home internet. My advertised tier is 1100/300Mbps , and i am consistently getting less than 100Mbps upload. A few notes: my overall connection is fine. My download speeds are 1100+Mbps. So everything is 'ok' overall, but the uploads cannot reach beyond 100. I have a netgear cbr750. I do notice that the upstream light on the modem is blinking often as if searching for upstream channels. Has anyone experienced similar issue, and would you mind sharing the resolution? Thanks for any input.
XfinityShawn
Official Employee
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1.8K Messages
12 days ago
@girarja Have you tried any troubleshooting from our Xfinity app? Are you noticing this drop in upload speed during specific tasks like working from home or gaming?
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zandor60657
Contributor
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217 Messages
12 days ago
Can you log onto your mesh kit and post the cable signal stats? They should be somewhere in the menus. You'll see stuff in there like SNR/Signal to Noise (for downstream) and dBmV. There's some info about it in this sticky post: Internet Troubleshooting Tips | Xfinity Community Forum It's generally best to cut and paste them into the forums rather than taking a screen shot. The forum does really well with cut and pasted tables from simple web pages like routers usually generate and the result is generally far more readable than a screenshot. So try cut & paste first and if the result is bad grab a screenshot.
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zandor60657
Contributor
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217 Messages
12 days ago
That partially explains why you're not getting anywhere near 300 up. You need an upstream OFDMA channel for that sort of upload speed. I'm surprised you're getting 75. I was stuck at 40 until I got a working OFDMA channel and I was on a higher speed plan. The thing it doesn't explain is why you don't have one if you're supposed to be on an 1100/300 plan.
Netgear CBR750 is on the supported list for higher upload speeds so it ought to work, but it won't without the OFDMA channel. Time to bother Comcast.
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girarja
Regular Visitor
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7 Messages
11 days ago
Update: The issue remains. The agent said to give it 24 hours so we will see (I am skeptical). For now, here is more information:
- A point I did not make previously: THE FASTER UPLOADS HAVE WORKED FINE BEFORE
- My modem's (Netgear CBR750) specification for upload speeds according to Xfinity compatible devices list is "Up to 471 Mbps", which is well within spec for a 300 Mbps upload tier. I am still getting less than 100.
- I was able to get a copy of the OFDMA signal levels when the upstream is ranging:
Upstream OFDMA Channels
Channel
Lock Status
Modulation/Profile ID
Channel ID
Frequency
Power
1
Locked
0
41
36200000 Hz
34.2 dBmV
2
Not Locked
0
0
0 Hz
0.0 dBmV
But that one locked channel drops when it cannot fully connect and it goes back to no locked channels as noted in previous post.
And the logs:
Aug 14 2025 17:59:09
Warning (5)
RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW
Aug 14 2025 17:59:14
Critical (3)
No Ranging Response received - T3 time-out
Aug 14 2025 17:59:25
Warning (5)
Initializing Channel Timeout Expires - Time the CM can perform initial ranging on all upstream channels in the TCS has expired
Aug 14 2025 17:59:25
Warning (5)
TCS Partial Service
Aug 14 2025 17:59:25
Notice (6)
US profile assignment change. US Chan ID: 41
So this all seems to point to a signal issue with the upstream OFDMA (I think?).
We will see what Comcast says.
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