Thanks for the link. I had not heard of this project, though I knew about CERN's experiments with synchronous ethernet. Tiny nit though - the plan was never to sync over the internet, with its variable latency and multiple PHY formats, but instead to provide an ethernet network with links up to 10km long that can provide a timing and phase reference for the LHC.

The idea of just utilizing the bidirectionally continuously active transmission lines of 1000BASE-T to essentially mutually PLL over the highly symmetric please delay wiring repurposing the existing carrier/clock recovery and garnishing with some actual data on top (clock comparing/time sync, configuration), is just ingenious.

IMO this counts as hacker spirit already.

Just a shame the hardware is completely out of the "fun project" price range, even if substantially less fancy components would suffice for most non-CERN use cases of White Rabbit... e.g. the mentioned synchronous Ethernet, and utilization of single frequency network [0] capabilities for WiFi.

[0]: https://en.wikipedia.org/wiki/Single-frequency_network