Gigabit plan stuck at ~40 Mbps upload with Hitron CODA56 despite OFDMA OPERATE

Hi, I’m having what appears to be a modem provisioning / upload speed profile issue.

I have Xfinity’s 1 Gig Internet plan, and my current Broadband Facts disclosure lists typical speeds of approximately 1172 Mbps download / 117 Mbps upload.

My download performance is normal, but upload is consistently capped around 38–40 Mbps:

UniFi UCG-Fiber WAN speed test: about 1106 Mbps down / 40.2 Mbps up
Speedtest.net: about 37.98 Mbps upload

My setup is:

Customer-owned Hitron CODA56
CODA56 connected to a UniFi UCG-Fiber
Ethernet link is 2.5 GbE full duplex
Smart Queues/QoS/rate limiting are disabled

I just power-cycled the modem and retested after it freshly registered with the network. The CODA56 diagnostics show:

DOCSIS 3.1 OFDMA upstream channel: OPERATE
OFDMA upstream bandmargin: 0;">Since the modem is successfully operating on the enhanced/mid-split OFDMA upstream but upload remains around 40 Mbps, could an Xfinity employee please check the following:
- modem bootfile/config file
- account upload speed profile
- customer-owned modem equipment coding
- whether the CODA56 is provisioned for the current 100 Mbps enhanced upload tier
- whether any old/legacy modem profile is still attached to the account
I’ve found other Xfinity Community cases where CODA56 customers stuck around 40 Mbps upload were corrected after the bootfile/account provisioning was fixed, so I’d appreciate someone checking that before scheduling a field technician.

Thanks!

Responses

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EG

Expert

•

120.7K Messages

1 hour ago

Concern moved here to the Customer Service help section for greater exposure to Comcast corporate employees (The Digital Care Team) for assistance.

user_k0faqs

Visitor

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4 Messages

1 hour ago

Additional information that may help narrow this down:

I checked my Xfinity equipment/account page. It correctly identifies my modem as a Hitron CODA56 and says it supports enhanced speeds, with up to 455 Mbps wired upload capability.

However, under Your Plan, Xfinity currently shows:

Download Speed: Up to 1000 Mbps
Upload Speed: 35 Mbps

That lines up almost exactly with my real-world results of approximately 38–40 Mbps upload.

My current Broadband Facts disclosure, however, lists approximately 117 Mbps typical upload for my 1 Gig plan.

The CODA56 also shows its DOCSIS 3.1 OFDMA upstream channel in OPERATE state with 44.4 MHz bandwidth, so the modem is successfully connected to the enhanced/mid-split upstream plant.

This makes me suspect my account/modem is still assigned the legacy 35 Mbps upload profile rather than the current enhanced 100 Mbps profile. Could the Digital Care team please verify the account speed tier, equipment coding, and modem bootfile/configuration?

XfinityJon

Official Employee

•

1.7K Messages

1 hour ago

Good afternoon user_k0faqs. I can certainly understand your concerns. Have you made any changes to your plan recently? What troubleshooting steps have you taken so far?

user_k0faqs

Visitor

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4 Messages

Good afternoon! I have not made any recent changes to my plan. I’ve been on the 1 Gig plan since roughly late May/early June 2026.

Troubleshooting completed so far:

Power-cycled the Hitron CODA56 and confirmed it freshly re-registered with Xfinity
Confirmed the modem-to-router link is 2.5 GbE full duplex
Confirmed Smart Queues/QoS/rate limiting are disabled
Tested directly from my UniFi UCG-Fiber gateway: approximately 1106 Mbps down / 40.2 Mbps up
Separate Speedtest.net test: approximately 37.98 Mbps upload
Confirmed the CODA56 DOCSIS 3.1 OFDMA upstream channel is in OPERATE state, with 44.4 MHz bandwidth
Upstream power levels are approximately 42.8–43.5 dBmV

I also found that my Xfinity account page currently shows “Upload Speed: 35 Mbps” under my 1 Gig plan, while my Broadband Facts disclosure shows approximately 117 Mbps typical upload. The modem itself is correctly identified as a Hitron CODA56 and Xfinity’s equipment page says it supports enhanced speeds.

Because my measured upload closely matches the 35 Mbps account profile, could you please check whether my account/modem is still provisioned on the legacy 35 Mbps upload profile, and verify the bootfile/config file and equipment coding for the current 100 Mbps enhanced upload tier?

1 hour ago

XfinityJon

Official Employee

•

1.7K Messages

I can certainly take a look.

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1 hour ago

user_k0faqs

Visitor

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4 Messages

Thanks Jon! I've just sent the direct message.

35 minutes ago

Customer Service

user_k0faqs

Gigabit plan stuck at ~40 Mbps upload with Hitron CODA56 despite OFDMA OPERATE

EG

user_k0faqs

XfinityJon

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XfinityJon

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