09-21-2022 10:24 PM - edited 09-21-2022 10:24 PM
Yep. This is correct. Google/YouTube, and a few other large providers, use UDP (with TCP as fallback) to speed up video delivery and improve latency of connections. QUIC and DTLS for example. On the Intel NICs you have to disable both TCP and UDP Checksum Offloading for IPv6 to completely solve the problem. Intel's fix is workable but incomplete.
Disabling UDP for IPv6 worked both for my youtube buffering problems and general image/cookie loading problems after some kind of firmware update was pushed to verizon routers recently.
There was no firmware update to Verizon equipment. This issue is completely solved by disabling UDP and TCP checksum offload in the device driver for Intel network interfaces.