tgingold

For a first approximation, you can assume A->B and B->A travel times are equal.

And because optical links are used, the asymmetry is mainly due to the wavelength difference which is known.

In a white-rabbit network you don't need atomic clocks on each node. One atomic clock is enough, its frequency is distributed over the network.

Only over fiber. Copper SFPs are not deterministic enough to precisely synchronize networks.