How to detect ISP Throttling / Shaping?

[mmurrell]

Apologies if this is posted in the incorrect forum.

To make a long story very short, I suspect my ISP is shaping / interrupting / throttling my traffic, but they assure me they do not. The question specifically is how to detect this, and work around it if possible.

I recently switched my networking stack to PFSense and have been absolutely thrilled with everything about it. I do have a challenge, specifically with respect to video streaming. We have 4 FireTV devices, one wired and the other three wireless. We currently stream through Netflix, Hulu, and Disney+. I will admit that we are heavy internet users and probably in a top percentile.

Most of the time it will run fine, but occasionally the stream will crash. Switching to a different stream or service will fail. Occasionally when it does, the FireTV will fail to load even the home screen, showing the dreaded 'Home is not available.' Usually the only solution is to walk away and later it will be come back online as if nothing happened. There is one data point that I'm having trouble reconciling: During the times of interruption, I can run a Speed Test from my phone on WiFi or from my desktop on the LAN and I get full speed. The internet is entirely operational during this time. This leads me to believe that my service is being actively shaped / interrupt.

Spectrum Internet, 400mbs service.
Network architecture: Cable Modem -> PFSense -> Network Switch (GigE) -> TP-Link Access Point

Here is a brief list of things I've tried:

• Using iPerf to measure LAN bandwidth during outage windows.
• Restarting FireTVs
• Switching FireTVs from Wired to Wireless and vice-versa
• Resetting FireTVs to factory settings
• Restarting Wireless Access Point
• Restarting PFSense
• Restarting Cable Modem
• Port Mirroring / Packet Capture at the switch and router level during periods of outage. I have the packet dumps, but I have no idea what to look for.
• Contacting ISP Tech Support. They reviewed the modem stats, including SNR, Power, and missed packets and had no concerns. Their only complaint was that my uptime showed 60+ days online and I should reboot.

I'm running out of troubleshooting ideas. Ideas include

• Switching to a different ISP (unable; there are no others servicing my area)
• Switching to business class with the same ISP (I assume they would not shape business class)
• Create VLAN and tunnel all FireTV traffic through VPN.
• Dropping the Hulu stream and moving to the ISP's TV Stream (I assume they would not shape their own service)

Thanks for reading. Any help the community could offer would be greatly appreciated.