Starting during the upcoming major LHC shutdown (2019-2021), the ATLAS experiment at
CERN will move to the Front-End Link eXchange (FELIX) system as the interface between
the data acquisition system and the trigger and detector front-end electronics. FELIX will function as a router between custom serial links and a commodity switch network, which will use
industry standard technologies to communicate with data collection and processing components.
This paper describes the FELIX system design as well as the results of the ongoing development