TCP BBR vs Cubic: Fix Slow Transfers on Lossy Links

by Danila Vershinin, October 31, 2026

Cubic collapsed to 20 KB/s on a lossy long-haul path. BBR on the sender made it up to 50x faster, and a relay around the bad hop made it fast every time. How to diagnose with ss and mtr, enable BBR (even on a live socket), and get it on CentOS 7.