"The plan is to start with Layer 3 routing functions in the MLNX-OS stack."
Huh? Quagga is already open-source.
"and then move on to the Layer 2 switching functions "
Their "Layer 2 Ethernet code" is an unholy mashup of their own code and the code Mellanox got when they bought Voltaire, neither of which ever caught on.
So their strategy is to give it away and hope that others will improve it, like Linux, to the point where it will actually be competitive at some point?!? This should be really entertaining.