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Upstream OFDMA Causing T3/T4 Timeouts – Need CMTS Provisioning Fix (Netgear CM3000, 2 Gbps Plan)
After countless hours today with several virtual chats, live on the phone support, and “Tier 2” transfers i’m trying this as a last hopeful resort.
Hi Xfinity Support,
I'm having persistent internet drops that appear directly tied to upstream OFDMA instability. I’ve already had a technician visit, and phone support has stated OFDMA was disabled — but my modem logs and status page show otherwise.
📦 Setup:
Modem: Netgear CM3000 (DOCSIS 3.1, Xfinity-approved)
Plan: 2 Gbps
Connection: Wired and wireless drops
Symptoms:
Frequent disconnections
Event logs full of
T3 timeouts
,T4 timeouts
, andno unicast ranging opportunities
Drops correlate with OFDMA Channel locking or flapping
Key Log Indicators:
Started Unicast Maintenance Ranging - No Response received - T3 time-out
16 consecutive T3 timeouts
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
OFDMA Channel 1 = Locked
OFDMA Channel 2 = Not Locked
Profile IDs: 12, 13
Power levels around 37.3 dBmV
What I've Tried:
Power-cycled modem
Factory reset modem
Tech visit (confirmed signals look clean)
Xfinity phone support says they "disabled OFDMA", but modem is still receiving OFDMA provisioning from CMTS
Request:
I’m requesting that upstream OFDMA be fully disabled at the CMTS level:
A new provisioning config file pushed to my modem that excludes OFDMA upstream channels
Verification that Profiles 12/13 are no longer being assigned
Confirmation from engineering that the CMTS override is in place
No Responses!