https://www.theregister.co.uk/2018/06/04/ietf_draft_proof_of_transit/

Virtualization changes everything – and in the case of the routers that keep the Internet working, it's not always in a good way.

Over the years, the IETF has accepted a variety of proposals that let network admins stipulate where their packets will go, under working groups like Internet Traffic Engineering and Service Function Chaining.