Regular Visitor
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8 Messages
Gigabit plan label shows 117 Mbps upload, but CM3000 has no upstream OFDMA lock and only gets ~41 Mbps
Hi, I’m trying to understand whether my Gigabit service is correctly provisioned for enhanced upload speeds.
My Xfinity broadband facts label for my 1000 Mbps plan shows:
Typical download speed: 1170 Mbps
Typical upload speed: 117 Mbps
Typical latency: 14 ms
I recently upgraded from a Motorola MB8600 to a Netgear CM3000. The CM3000 is connected from its 2.5 GbE port to the 2.5 GbE WAN port on my Asus ZenWiFi Pro ET12 router using a short Cat7 cable.
After the upgrade, download improved as expected, but upload did not:
2026/6/23 23:31 (CM3000): 1119.33 Mbps down / 41.05 Mbps up / 9.69 ms ping
I checked the CM3000 status pages. Hardware version is 1.01 and cable firmware version is V6.01.04. The modem reports DOCSIS 3.1, CM certificate installed, BPI+ enabled, and Cable Diagnostic status “Good.”
Current downstream levels look clean: downstream QAM channels have good SNR/power and 0 uncorrectables, and downstream OFDM is locked with 0 uncorrectables. The event log only shows startup-time T3/T4/SYNC messages around registration/reset, plus a TLV-11 unrecognized OID notice and a downstream profile assignment change after coming online. I don’t see ongoing errors in the log.
However, upstream OFDMA is not locked:
Upstream OFDMA Channels:
Channel 1: Not Locked, 0 Hz
Channel 2: Not Locked, 0 Hz
The modem is only using legacy ATDMA upstream channels:
10.4 MHz, 16.4 MHz, 22.8 MHz, 29.2 MHz, 35.6 MHz, and 40.4 MHz
Upstream power is around 42.8-43.3 dBmV.
Possibly relevant line context: there are no splitters or extra inside coax in my setup. The modem is connected with about 12 inches of coax coming directly from outside the house. I previously saw severe downstream impairments/uncorrectables on specific channels at this location with an MB8600, so if the account/provisioning looks correct, could this be a drop/tap/plant issue or a legacy filter preventing mid-split/OFDMA upstream?
This looks like I’m still on the legacy upload path/profile even though my broadband label says typical upload should be 117 Mbps.
Can an Xfinity employee please check whether:
- My service address/node is enabled for enhanced/Next Gen upload speeds
- My account is provisioned for the correct enhanced upload speed profile
- The CM3000 has the correct bootfile/config file
- The CMTS is advertising/allowing upstream OFDMA for my modem
- There is a legacy filter, drop issue, splitter issue, or plant issue preventing mid-split upstream operation
I’m happy to provide account details, modem MAC, and screenshots privately if requested.
XfinityAirelle
Official Employee
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3.3K Messages
3 hours ago
Hi there! First, thank you for providing such a detailed breakdown. It sounds like you've already done quite a bit of troubleshooting and gathered some excellent diagnostic information.
Based on what you've shared, your observations seem reasonable. While we can't determine provisioning, bootfile assignments, OFDMA status, or plant conditions from a public post alone, the fact that you're consistently seeing upload speeds around 41 Mbps despite a Broadband Facts label showing a typical upload speed of 117 Mbps certainly warrants a closer look.
The details regarding the upstream OFDMA channels not being locked, combined with the modem operating solely on legacy ATDMA upstream channels, could indicate that the modem is not utilizing the enhanced upload path. Whether that's due to provisioning, network availability, plant conditions, filters, or another factor would require account and network-level review.
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user_i6h83k
Regular Visitor
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8 Messages
19 minutes ago
Thanks for the quick response. I’ll send a direct message to Xfinity Support with my full name and service address.
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