CM2050V - Latest Firmware Preventing 2.5 Gbps Passthrough on Ethernet Port

CrimpOn,

Thanks for the reply.

I miss identified the Fluke tester in the OP, it was the LinkIQ which is capable of 10 Gbps (borrowed from work).  However note, that the Xfinity tech's ethernet tester was also rated at 10Gbps, and it also showed 987 mbps consistently, so the two test equipment were consistent.

As far as the router question, Yes, it has the build in speed test and along with other devices on the network was used to first identify the anomaly.

The router has a 2.5 Gbps WAN port and as stated in the OP, negotiates at 2500 mbps Full Duplex.   Prior to the v10.01.03 updates (and still on the 1 Gbps plan), I was able to consistently achieve 820's to 1012 mbps using the built in speed test.  The speed test numbers have not changed ( I still get those speeds), on the new 2.1 Gbps plan), but I'm not getting the 1800-1900 mbps that the new Xfinity plan provides, and caps out at the 900 mbps range.

The cable  connection at the modem is 2300 mbps, but once passing through the modem and out the ethernet port of the modem, it drops to 987 mbps (tester directly connected to the modem).

This would in theory indicate some kind of internal issue of the modem (I was at first thinking hardware version, but FURRYe38, indicated that all the models of CM2050V have the same HW version), so HW version was ruled out at this point, unless there is a way to internally check the ethernet PHY for compliance, and it passing all consumer and ISP operator diagnostic, it is not apparent that the PHY is the problem.

Regarding the support ticket, I agree!  Although these modems are ment to have at least a 7-10 year life span (or until DOSIS 4 arrives), it should be support for "firmware/internal", and the consumer should have a simple way to open a ticket for FW/HW level issues.

All of the consumer and ISP Operator level troubleshooting has been exhausted at this point, so I am not looking for things to try outside of the modem, as all of the standard and professional tracing/troubleshooting back to the modem for a problem has been done.  All logs and connections status have been verified by Xfinity as good.