Contributor
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35 Messages
2 Gbps Plan – Netgear CM3000 Only Locking One OFDM/OFDMA Channel After Two Modems & Tech Visit
Hi Xfinity Community. I'm a very long time Xfinity customer. I'm hoping someone from the Xfinity team can help escalate this to the appropriate back-end group.
I’ve been working through an issue for the past 9 days involving my 2 Gbps service tier and a Netgear CM3000 modem. I’ve had a field technician visit, spoken with an escalation manager via phone and text messages multiple times, and even purchased a second brand‑new CM3000 (overnighted at my own expense) to rule out hardware. Unfortunately, the issue persists across both modems.
Summary of the Issue
- My CM3000 only locks one OFDM downstream channel and one OFDMA upstream channel.
- The second OFDM/OFDMA channels never activate, which keeps speeds capped around ~700 Mbps even when connected directly to the modem.
- All 32 DOCSIS 3.0 downstream bonded channels lock perfectly with excellent power levels and SNR.
- A field tech confirmed the line is clean and DOCSIS 3.1 capable.
- Netgear has confirmed the modem is operating to their specifications and that the issue appears to be incorrect provisioning on the ISP side.
- Netgear also confirmed:
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- All 32 downstream bonded channels are locking as expected
- IP Provisioning Mode is Honor MDD / IPv6 only, which is normal
- Their support case remains open in case Xfinity needs additional vendor assistance
- Two different CM3000 units show identical behavior, which strongly suggests a CMTS provisioning or bootfile mismatch.
Troubleshooting Completed
- Field tech visit with full diagnostics
- Multiple provisioning attempts
- Replacement modem (both were brand‑new CM3000)
- Direct‑to‑modem speed tests
- Netgear support engagement (Case #49435683)
- Signal levels verified as excellent
- No in‑home wiring issues
- No router involved during testing
What I’m Requesting
I’m hoping someone can help verify whether the correct 2 Gbps DOCSIS 3.1 bootfile is being assigned to my modem, and whether the CMTS entry for my account/MAC needs to be cleared and reassigned.
Current modem MAC: [Edited: "Personal Information"]
Modem model: Netgear CM3000
Netgear Case: 49435683
Everyone I’ve spoken with has been kind and helpful, but after 9 days and two modems, I’m hoping to get this in front of the right backend team who can check the provisioning side.
Thank you to anyone who can help move this forward.
Accepted Solution
user_db131
Contributor
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35 Messages
14 hours ago
Quick update now that I’ve enabled Bridge Mode on the new Xfinity Gateway, with my Orbi 970 mesh Wi‑Fi base station connected to Gateway Port 1.
Bridge Mode activation:
The gateway rebooted cleanly, disabled its internal Wi‑Fi as expected, and my Orbi 970 network immediately pulled a public IP. Everything has been stable since the transition.
Initial performance testing:
I’ve run a series of wired speedtests from my workstation after enabling Bridge Mode. Here’s what I’m seeing so far:
These results have been consistent across multiple runs.
Additional tools used:
Next steps:
I’ll continue testing over the next couple of days, including more comparisons across different servers and times of day, as well as running simultaneous speedtests from multiple workstations. I’ll post another update once I’ve gathered more data.
At this point, I think it’s reasonable for Xfinity to close my ticket. I’ll open a new ticket if I uncover anything unusual going forward. While I had hoped the Netgear CM3000 would work perfectly with Xfinity out of the box, the Xfinity Gateway is exceeding my expectations.
Thanks again to the Xfinity forum team for the guidance throughout this process — especially XfinityJohn, who went above and beyond. I also appreciate Xfinity assigning an Executive Customer Relations Specialist to my case who was helpful. The bottom line is that the Xfinity Gateway in Bridge Mode is working well so far, and my network is finally stable and delivering the speeds I can trust.
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XfinityAbby
Official Employee
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518 Messages
10 days ago
Hello @user_db131. Thank you for providing all of that information. I can go ahead and check that boot file and CMTS entry.
Please send us a direct message with your full name and address so that we can assist you further.
To send a "Direct Message" to Xfinity Support:
Click "Sign In" if necessary
Click the "Direct Messaging" icon or https://forums.xfinity.com/direct-messaging
Click the "New message" (pencil and paper) icon
The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there
- As you are typing a drop-down list appears. Select "Xfinity Support" from that list
- An "Xfinity Support" graphic replaces the "To:" line
Type your message in the text area near the bottom of the window
Press Enter to send it.
(edited)
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plumld
Contributor
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289 Messages
9 days ago
Just for info, I have a CM3000 with a 1.3 Gbps plan. I only get the one OFDM channel locked and am getting 1.5 Gbps. All 32 QAM channels are locked. Even with just the QAM channels locked, you should get at least 1Gbps (Docsis 3.0).
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EG
Expert
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115.3K Messages
9 days ago
@user_db131 @XfinityAbby
Please circle back here and post any possible solutions for the issue here in these open public forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.
(edited)
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user_db131
Contributor
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35 Messages
8 days ago
Quick update: XfinityJohnG has submitted an escalation to the Advanced Repair / backend engineering team (ticket [Edited: "Personal Information"]). I’ll update the thread once I hear back from engineering. Thanks to everyone who’s been helping so far.
(edited)
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user_db131
Contributor
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35 Messages
3 days ago
Update:
Two field technicians visited and confirmed that the physical layer, wiring, and signal levels are all within specifications. Multiple reprovisioning attempts were performed, and I also tested with two separate CM3000 units. In all cases, the modem continued to lock only one OFDM downstream channel and one OFDMA upstream channel.
I had hoped Xfinity’s engineering / Advanced Repair team would be able to review the CMTS provisioning layer to determine why the second DOCSIS 3.1 channels were not being assigned, but I was informed by Xfinity’s Executive Customer Relations Specialist that no further engineering investigation will be performed. Xfinity has advised me to switch to an Xfinity‑branded modem, as they will not be pursuing additional work on this issue.
I appreciate the efforts of the Xfinity technicians and support teams who assisted, but the underlying DOCSIS 3.1 bonding issue remains unresolved on the CM3000. I’m sharing this update in case it helps others who may encounter similar behavior.
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EG
Expert
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115.3K Messages
3 days ago
@user_db131
FWIW and AFAIK, some local systems still have only one of each available on them.
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EG
Expert
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115.3K Messages
3 days ago
@user_db131
Ok. Was just throwing something to consider out there.
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user_db131
Contributor
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35 Messages
2 days ago
Update: Netgear reviewed the case and asked me to request an escalation to Xfinity Tier 2. They continue to believe the issue is on the Xfinity side.
I’ve since moved off the Netgear modem and switched to an Xfinity Gateway per multiple Xfinity personnel recommendations.
However, I’m unable to log into
10.0.0.1— the admin password printed on the bottom of the unit does not work, and the gateway will not perform a true factory reset (the WiFi SSID never reverts).I’m currently waiting for assistance from Xfinity support to reset or replace the gateway so I can enable Bridge Mode and allow the Xfinity Gateway to properly support my Orbi mesh network.
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EG
Expert
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115.3K Messages
2 days ago
They recently updated the gateway's firmware. You have to turn on admin access in the app now;
https://www.xfinity.com/support/articles/admin-tool-access
Open the Xfinity App. (You'll need a working connection for this step).
Go to the WiFi tab.
Select View WiFi equipment and open Advanced Settings.
Select Admin Tool online access.
Slide the toggle button to Allow Admin Tool access (ON).
Select Save.
After that, you should be able to navigate to http://10.0.0.1
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EG
Expert
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115.3K Messages
2 days ago
@user_db131
YW, and glad it worked !
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