3 Messages
No Upstream OFDMA on Arris S33 After Upgrading to 2 Gbps Plan
Hi, I recently upgraded to the 2 Gbps plan with 300 Mbps upload, but my Arris S33 modem is only bonding to SC-QAM channels on the upstream—there’s no OFDMA.
OFDMA is active on the downstream, so DOCSIS 3.1 is working, but my upload speeds are much lower than expected (~40 Mbps instead of 300+ Mbps).
I’ve restarted my modem and checked 192.168.100.1, but my upstream is still missing OFDMA. I contacted support, but they only told me to reboot and didn’t check my provisioning.
Can someone confirm if upstream OFDMA is enabled in my area, and if not, can my modem be reprovisioned correctly for the 2 Gbps plan?
Thanks!
BruceW
Gold Problem Solver
•
26.3K Messages
2 months ago
Realize that although Comcast calls some devices "Compatible" and some "Recommended", for all but a few devices those designations only mean "compatible/recommended for use with their Internet service", and not necessarily approved for the upload speeds introduced in 2023.
The S33 is not compatible with those speeds. Only a few retail devices are. See the "Next Gen" list at the top of the "All Compatible Devices" PDF linked near the bottom of https://www.xfinity.com/support/devices (at the moment that link points to https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2024.09.18%20Full%20List%20of%20Compatible%20Devices.pdf, but this changes from time to time).
For faster upload you need one of Comcast's newer rental gateways (XB6, XB7, XB8) or one of the few retail devices shown in the "Next Gen Speed Tier" group at the top of the "All Compatible Devices" PDF:
Comcast/Xfinity could make all of this much simpler and clearer, but they have chosen not to do so.
For additional requirements for faster upload see https://forums.xfinity.com/conversations/customer-service/upload-speeds/677b01a7121aae71d76926bf?commentId=677b05b23423b47b4071a8d0&replyId=677bd66e7699a97c89069e62
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