This is a follow-on to a question posted on stack overflow about whether it is possible to determine the one-way latency of a point to point connection without using externally synchronized clocks - turns out it isn't.

Now the question here is if such asymmetric latencies (where the trip time from A->B is materially different than the trip time B->A) is common in practice? Why?

What about in a typical data center LAN environment? What about across the internet backbone? What about across connections that have asymmetric bandwidth, such as many DSL, satellite or Cable connections?

Thanks!